Commit Graph

497 Commits

Author SHA1 Message Date
Al Viro
330d57fb98 [PATCH] Fix sysctl unregistration oops (CVE-2005-2709)
You could open the /proc/sys/net/ipv4/conf/<if>/<whatever> file, then
wait for interface to go away, try to grab as much memory as possible in
hope to hit the (kfreed) ctl_table.  Then fill it with pointers to your
function.  Then do read from file you've opened and if you are lucky,
you'll get it called as ->proc_handler() in kernel mode.

So this is at least an Oops and possibly more.  It does depend on an
interface going away though, so less of a security risk than it would
otherwise be.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-08 17:57:30 -08:00
Linus Torvalds
d27ba47e7e Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6 2005-11-07 18:42:23 -08:00
Al Viro
7b7b1ace2d [PATCH] saner handling of auto_acct_off() and DQUOT_OFF() in umount
The way we currently deal with quota and process accounting that might
keep vfsmount busy at umount time is inherently broken; we try to turn
them off just in case (not quite correctly, at that) and

  a) pray umount doesn't fail (otherwise they'll stay turned off)
  b) pray nobody doesn anything funny just as we turn quota off

Moreover, LSM provides hooks for doing the same sort of broken logics.

The proper way to deal with that is to introduce the second kind of
reference to vfsmount.  Semantics:

 - when the last normal reference is dropped, all special ones are
   converted to normal ones and if there had been any, cleanup is done.
 - normal reference can be cloned into a special one
 - special reference can be converted to normal one; that's a no-op if
   we'd already passed the point of no return (i.e.  mntput() had
   converted special references to normal and started cleanup).

The way it works: e.g. starting process accounting converts the vfsmount
reference pinned by the opened file into special one and turns it back
to normal when it gets shut down; acct_auto_close() is done when no
normal references are left.  That way it does *not* obstruct umount(2)
and it silently gets turned off when the last normal reference to
vfsmount is gone.  Which is exactly what we want...

The same should be done by LSM module that holds some internal
references to vfsmount and wants to shut them down on umount - it should
make them special and security_sb_umount_close() will be called exactly
when the last normal reference to vfsmount is gone.

quota handling is even simpler - we don't use normal file IO anymore, so
there's no need to hold vfsmounts at all.  DQUOT_OFF() is done from
deactivate_super(), where it really belongs.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 18:18:09 -08:00
Hugh Dickins
dedeb0029b [SPARC64] mm: context switch ptlock
sparc64 is unique among architectures in taking the page_table_lock in
its context switch (well, cris does too, but erroneously, and it's not
yet SMP anyway).

This seems to be a private affair between switch_mm and activate_mm,
using page_table_lock as a per-mm lock, without any relation to its uses
elsewhere.  That's fine, but comment it as such; and unlock sooner in
switch_mm, more like in activate_mm (preemption is disabled here).

There is a block of "if (0)"ed code in smp_flush_tlb_pending which would
have liked to rely on the page_table_lock, in switch_mm and elsewhere;
but its comment explains how dup_mmap's flush_tlb_mm defeated it.  And
though that could have been changed at any time over the past few years,
now the chance vanishes as we push the page_table_lock downwards, and
perhaps split it per page table page.  Just delete that block of code.

Which leaves the mysterious spin_unlock_wait(&oldmm->page_table_lock)
in kernel/fork.c copy_mm.  Textual analysis (supported by Nick Piggin)
suggests that the comment was written by DaveM, and that it relates to
the defeated approach in the sparc64 smp_flush_tlb_pending.  Just delete
this block too.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-07 14:09:01 -08:00
Adrian Bunk
b26b9bc582 [PATCH] unexport uts_sem
I didn't find any possible modular usage in the kernel.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:54:07 -08:00
Adrian Bunk
4664957b8e [PATCH] unexport idle_cpu
I didn't find any possible modular usage in the kernel.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:54:07 -08:00
Adrian Bunk
47bdfb96de [PATCH] unexport console_unblank
I didn't find any possible modular usage of console_unblank in the
kernel.

This patch was already ACK'ed by Alan Cox.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:54:07 -08:00
Randy Dunlap
b8887e6e8c [PATCH] kernel-docs: fix kernel-doc format problems
Convert to proper kernel-doc format.

Some have extra blank lines (not allowed immed.  after the function name)
or need blank lines (after all parameters).  Function summary must be only
one line.

Colon (":") in a function description does weird things (causes kernel-doc
to think that it's a new section head sadly).

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:55 -08:00
Randy Dunlap
1e5d533142 [PATCH] more kernel-doc cleanups, additions
Various core kernel-doc cleanups:
- add missing function parameters in ipc, irq/manage, kernel/sys,
  kernel/sysctl, and mm/slab;
- move description to just above function for kernel_restart()

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:55 -08:00
Ananth N Mavinakayanahalli
d217d5450f [PATCH] Kprobes: preempt_disable/enable() simplification
Reorganize the preempt_disable/enable calls to eliminate the extra preempt
depth.  Changes based on Paul McKenney's review suggestions for the kprobes
RCU changeset.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:46 -08:00
Ananth N Mavinakayanahalli
3516a46042 [PATCH] Kprobes: Use RCU for (un)register synchronization - base changes
Changes to the base kprobes infrastructure to use RCU for synchronization
during kprobe registration and unregistration.  These changes coupled with the
arch kprobe changes (next in series):

a. serialize registration and unregistration of kprobes.
b. enable lockless execution of handlers. Handlers can now run in parallel.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:46 -08:00
Ananth N Mavinakayanahalli
e65845235c [PATCH] Kprobes: Track kprobe on a per_cpu basis - base changes
Changes to the base kprobe infrastructure to track kprobe execution on a
per-cpu basis.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:45 -08:00
Christoph Hellwig
481bed4542 [PATCH] consolidate sys_ptrace()
The sys_ptrace boilerplate code (everything outside the big switch
statement for the arch-specific requests) is shared by most architectures.
This patch moves it to kernel/ptrace.c and leaves the arch-specific code as
arch_ptrace.

Some architectures have a too different ptrace so we have to exclude them.
They continue to keep their implementations.  For sh64 I had to add a
sh64_ptrace wrapper because it does some initialization on the first call.
For um I removed an ifdefed SUBARCH_PTRACE_SPECIAL block, but
SUBARCH_PTRACE_SPECIAL isn't defined anywhere in the tree.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Mackerras <paulus@samba.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-By: David Howells <dhowells@redhat.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:42 -08:00
Tim Schmielau
8c65b4a604 [PATCH] fix remaining missing includes
Fix more include file problems that surfaced since I submitted the previous
fix-missing-includes.patch.  This should now allow not to include sched.h
from module.h, which is done by a followup patch.

Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:41 -08:00
David Gibson
796f8d9b98 [PATCH] FUTEX_WAKE_OP: enhanced error handling
The code for FUTEX_WAKE_OP calls an arch callback,
futex_atomic_op_inuser().  That callback can return an error code, but
currently the caller assumes any error is EFAULT, and will try various
things to resolve the fault before eventually giving up with EFAULT
(regardless of the original error code).  This is not a theoretical case -
arch callbacks currently return -ENOSYS if the opcode they are given is
bogus.

This patch alters the code to detect non-EFAULT errors and return them
directly to the user.

Of course, whether -ENOSYS is the correct return value for the bogus opcode
case, or whether EINVAL would be more appropriate is another question.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jamie Lokier <jamie@shareable.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:38 -08:00
Zach Brown
d55b5fdaf4 [PATCH] aio: remove aio_max_nr accounting race
AIO was adding a new context's max requests to the global total before
testing if that resulting total was over the global limit.  This let
innocent tasks get their new limit tested along with a racing guilty task
that was crossing the limit.  This serializes the _nr accounting with a
spinlock It also switches to using unsigned long for the global totals.
Individual contexts are still limited to an unsigned int's worth of
requests by the syscall interface.

The problem and fix were verified with a simple program that spun creating
and destroying a context while holding on to another long lived context.
Before the patch a task creating a tiny context could get a spurious EAGAIN
if it raced with a task creating a very large context that overran the
limit.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:38 -08:00
Matt Helsley
9f46080c41 [PATCH] Process Events Connector
This patch adds a connector that reports fork, exec, id change, and exit
events for all processes to userspace.  It replaces the fork_advisor patch
that ELSA is currently using.  Applications that may find these events
useful include accounting/auditing (e.g.  ELSA), system activity monitoring
(e.g.  top), security, and resource management (e.g.  CKRM).

Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:35 -08:00
Pavel Machek
47b90ffe5c [PATCH] swsusp: remove unused variable
Remove unused variable, and make code less evil that way.  Fix whitespace
around for-loop-like macro.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:29 -08:00
Pavel Machek
dc19d507b1 [PATCH] swsusp cleanups
This cleans spaces between * and pointer up, and adds "int" in "unsigned
int".

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:29 -08:00
Heiko Carstens
a4c4af7c8d [PATCH] cpu hoptlug: avoid usage of smp_processor_id() in preemptible code
Replace smp_processor_id() with any_online_cpu(cpu_online_map) in order to
avoid lots of "BUG: using smp_processor_id() in preemptible [00000001]
code:..." messages in case taking a cpu online fails.

All the traces start at the last notifier_call_chain(...) in kernel/cpu.c.
Since we hold the cpu_control semaphore it shouldn't be any problem to access
cpu_online_map.

The reason why cpu_up failed is simply that the cpu that was supposed to be
taken online wasn't even there.  That is because on s390 we never know when a
new cpu comes and therefore cpu_possible_map consists of only ones and doesn't
reflect reality.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:29 -08:00
Andrew Morton
7fd93cf30c [PATCH] posix-timers `unlikely' rejig
!unlikely(expr) hurts my brain.   likely(!expr) is more straightforward.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:24 -08:00
Oleg Nesterov
889dfafe83 [PATCH] improve scheduler fairness a bit
Do not transfer remaining time slice to another cpu on process exit.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-04 10:45:28 -08:00
Paul Mackerras
23fd07750a Merge ../linux-2.6 by hand 2005-10-31 13:37:12 +11:00
Tim Schmielau
4e57b68178 [PATCH] fix missing includes
I recently picked up my older work to remove unnecessary #includes of
sched.h, starting from a patch by Dave Jones to not include sched.h
from module.h. This reduces the number of indirect includes of sched.h
by ~300. Another ~400 pointless direct includes can be removed after
this disentangling (patch to follow later).
However, quite a few indirect includes need to be fixed up for this.

In order to feed the patches through -mm with as little disturbance as
possible, I've split out the fixes I accumulated up to now (complete for
i386 and x86_64, more archs to follow later) and post them before the real
patch.  This way this large part of the patch is kept simple with only
adding #includes, and all hunks are independent of each other.  So if any
hunk rejects or gets in the way of other patches, just drop it.  My scripts
will pick it up again in the next round.

Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:32 -08:00
Paul E. McKenney
b0423a0d9c [PATCH] Remove duplicate code in signal.c
Combine a bit of redundant code between force_sig_info() and
force_sig_specific().

Signed-off-by: paulmck@us.ibm.com
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:32 -08:00
Oleg Nesterov
ae6866c377 [PATCH] remove unneeded SI_TIMER checks
This patch removes checks for ->si_code == SI_TIMER from send_signal,
specific_send_sig_info, __group_send_sig_info.

I think posix-timers.c used these functions some time ago, now it sends
signals via send_{,group_}sigqueue, so these hooks are unneeded.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:32 -08:00
Oleg Nesterov
621d31219d [PATCH] cleanup the usage of SEND_SIG_xxx constants
This patch simplifies some checks for magic siginfo values.  It should not
change the behaviour in any way.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:31 -08:00
Oleg Nesterov
b67a1b9e4b [PATCH] remove hardcoded SEND_SIG_xxx constants
This patch replaces hardcoded SEND_SIG_xxx constants with
their symbolic names.

No changes in affected .o files.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:31 -08:00
Paul Jackson
4098f9918e [PATCH] sched: hardcode non-smp set_cpus_allowed
Simplify the UP (1 CPU) implementatin of set_cpus_allowed.

The one CPU is hardcoded to be cpu 0 - so just test for that bit, and avoid
having to pick up the cpu_online_map.

Also, unexport cpu_online_map: it was only needed for set_cpus_allowed().

Signed-off-by: Paul Jackson <pj@sgi.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:28 -08:00
Roland McGrath
708f430dcc [PATCH] posix-cpu-timers: fix overrun reporting
This change corrects an omission in posix_cpu_timer_schedule, so that it
correctly propagates the overrun calculation to where it will get reported
to the user.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:27 -08:00
Paul E. McKenney
a241ec65ae [PATCH] RCU torture-testing kernel module
This patch is a rewrite of the one submitted on October 1st, using modules
(http://marc.theaimsgroup.com/?l=linux-kernel&m=112819093522998&w=2).

This rewrite adds a tristate CONFIG_RCU_TORTURE_TEST, which enables an
intense torture test of the RCU infratructure.  This is needed due to the
continued changes to the RCU infrastructure to accommodate dynamic ticks,
CPU hotplug, realtime, and so on.  Most of the code is in a separate file
that is compiled only if the CONFIG variable is set.  Documentation on how
to run the test and interpret the output is also included.

This code has been tested on i386 and ppc64, and an earlier version of the
code has received extensive testing on a number of architectures as part of
the PREEMPT_RT patchset.

Signed-off-by: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:27 -08:00
Thomas Gleixner
ecea8d19c9 [PATCH] jiffies_64 cleanup
Define jiffies_64 in kernel/timer.c rather than having 24 duplicated
defines in each architecture.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:25 -08:00
Roland McGrath
7f2a525559 [PATCH] wait4 PTRACE_ATTACH race fix
Back about a year ago when I last fiddled heavily with the do_wait code, I
was thinking too hard about the wrong thing and I now think I introduced a
bug whose inverse thought I was fixing.

Apparently noone was looking too hard over much shoulder, so as to cite my
bogus reasoning at the time.  In the race condition when PTRACE_ATTACH is
about to steal a child and then the child hits a tracing event (what
my_ptrace_child checks for), the real parent does need to set its flag
noting it has some eligible live children.  Otherwise a spurious ECHILD
error is possible, since the child in question is not yet on the
ptrace_children list.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:24 -08:00
Coywolf Qi Hunt
7407251a0e [PATCH] PF_DEAD cleanup
The PF_DEAD setting doesn't belong to exit_notify(), move it to a proper
place.

Signed-off-by: Coywolf Qi Hunt <qiyong@fc-cn.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:23 -08:00
Jesper Juhl
40dc565122 [PATCH] cleanup for kernel/printk.c
- Removes some trailing whitespace

- Breaks long lines and make other small changes to conform to CodingStyle

- Add explicit printk loglevels in two places.

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:23 -08:00
David Howells
20e1129ab8 [PATCH] Keys: Get rid of warning in kmod.c if keys disabled
The attached patch gets rid of a "statement without effect" warning when
CONFIG_KEYS is disabled by making use of the return value of key_get().
The compiler will optimise all of this away when keys are disabled.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:23 -08:00
Andrea Arcangeli
30e0fca6c1 [PATCH] ptrace/coredump/exit_group deadlock
I could seldom reproduce a deadlock with a task not killable in T state
(TASK_STOPPED, not TASK_TRACED) by attaching a NPTL threaded program to
gdb, by segfaulting the task and triggering a core dump while some other
task is executing exit_group and while one task is in ptrace_attached
TASK_STOPPED state (not TASK_TRACED yet).  This originated from a gdb
bugreport (the fact gdb was segfaulting the task wasn't a kernel bug), but
I just incidentally noticed the gdb bug triggered a real kernel bug as
well.

Most threads hangs in exit_mm because the core_dumping is still going, the
core dumping hangs because the stopped task doesn't exit, the stopped task
can't wakeup because it has SIGNAL_GROUP_EXIT set, hence the deadlock.

To me it seems that the problem is that the force_sig_specific(SIGKILL) in
zap_threads is a noop if the task has PF_PTRACED set (like in this case
because gdb is attached).  The __ptrace_unlink does nothing because the
signal->flags is set to SIGNAL_GROUP_EXIT|SIGNAL_STOP_DEQUEUED (verified).

The above info also shows that the stopped task hit a race and got the stop
signal (presumably by the ptrace_attach, only the attach, state is still
TASK_STOPPED and gdb hangs waiting the core before it can set it to
TASK_TRACED) after one of the thread invoked the core dump (it's the core
dump that sets signal->flags to SIGNAL_GROUP_EXIT).

So beside the fact nobody would wakeup the task in __ptrace_unlink (the
state is _not_ TASK_TRACED), there's a secondary problem in the signal
handling code, where a task should ignore the ptrace-sigstops as long as
SIGNAL_GROUP_EXIT is set (or the wakeup in __ptrace_unlink path wouldn't be
enough).

So I attempted to make this patch that seems to fix the problem.  There
were various ways to fix it, perhaps you prefer a different one, I just
opted to the one that looked safer to me.

I also removed the clearing of the stopped bits from the zap_other_threads
(zap_other_threads was safe unlike zap_threads).  I don't like useless
code, this whole NPTL signal/ptrace thing is already unreadable enough and
full of corner cases without confusing useless code into it to make it even
less readable.  And if this code is really needed, then you may want to
explain why it's not being done in the other paths that sets
SIGNAL_GROUP_EXIT at least.

Even after this patch I still wonder who serializes the read of
p->ptrace in zap_threads.

Patch is called ptrace-core_dump-exit_group-deadlock-1.

This was the trace I've got:

test          T ffff81003e8118c0     0 14305      1         14311 14309 (NOTLB)
ffff810058ccdde8 0000000000000082 000001f4000037e1 ffff810000000013
       00000000000000f8 ffff81003e811b00 ffff81003e8118c0 ffff810011362100
       0000000000000012 ffff810017ca4180
Call Trace:<ffffffff801317ed>{try_to_wake_up+893} <ffffffff80141677>{finish_stop+87}
       <ffffffff8014367f>{get_signal_to_deliver+1359} <ffffffff8010d3ad>{do_signal+157}
       <ffffffff8013deee>{ptrace_check_attach+222} <ffffffff80111575>{sys_ptrace+2293}
       <ffffffff80131810>{default_wake_function+0} <ffffffff80196399>{sys_ioctl+73}
       <ffffffff8010dd27>{sysret_signal+28} <ffffffff8010e00f>{ptregscall_common+103}

test          D ffff810011362100     0 14309      1         14305 14312 (NOTLB)
ffff810053c81cf8 0000000000000082 0000000000000286 0000000000000001
       0000000000000195 ffff810011362340 ffff810011362100 ffff81002e338040
       ffff810001e0ca80 0000000000000001
Call Trace:<ffffffff801317ed>{try_to_wake_up+893} <ffffffff8044677d>{wait_for_completion+173}
       <ffffffff80131810>{default_wake_function+0} <ffffffff80137435>{exit_mm+149}
       <ffffffff801381af>{do_exit+479} <ffffffff80138d0c>{do_group_exit+252}
       <ffffffff801436db>{get_signal_to_deliver+1451} <ffffffff8010d3ad>{do_signal+157}
       <ffffffff8013deee>{ptrace_check_attach+222} <ffffffff80140850>{specific_send_sig_info+2

       <ffffffff8014208a>{force_sig_info+186} <ffffffff804479a0>{do_int3+112}
       <ffffffff8010e308>{retint_signal+61}
test          D ffff81002e338040     0 14311      1         14716 14305 (NOTLB)
ffff81005ca8dcf8 0000000000000082 0000000000000286 0000000000000001
       0000000000000120 ffff81002e338280 ffff81002e338040 ffff8100481cb740
       ffff810001e0ca80 0000000000000001
Call Trace:<ffffffff801317ed>{try_to_wake_up+893} <ffffffff8044677d>{wait_for_completion+173}
       <ffffffff80131810>{default_wake_function+0} <ffffffff80137435>{exit_mm+149}
       <ffffffff801381af>{do_exit+479} <ffffffff80142d0e>{__dequeue_signal+558}
       <ffffffff80138d0c>{do_group_exit+252} <ffffffff801436db>{get_signal_to_deliver+1451}
       <ffffffff8010d3ad>{do_signal+157} <ffffffff8013deee>{ptrace_check_attach+222}
       <ffffffff80140850>{specific_send_sig_info+208} <ffffffff8014208a>{force_sig_info+186}
       <ffffffff804479a0>{do_int3+112} <ffffffff8010e308>{retint_signal+61}

test          D ffff810017ca4180     0 14312      1         14309 13882 (NOTLB)
ffff81005d15fcb8 0000000000000082 ffff81005d15fc58 ffffffff80130816
       0000000000000897 ffff810017ca43c0 ffff810017ca4180 ffff81003e8118c0
       0000000000000082 ffffffff801317ed
Call Trace:<ffffffff80130816>{activate_task+150} <ffffffff801317ed>{try_to_wake_up+893}
       <ffffffff8044677d>{wait_for_completion+173} <ffffffff80131810>{default_wake_function+0}
       <ffffffff8018cdc3>{do_coredump+819} <ffffffff80445f52>{thread_return+82}
       <ffffffff801436d4>{get_signal_to_deliver+1444} <ffffffff8010d3ad>{do_signal+157}
       <ffffffff8013deee>{ptrace_check_attach+222} <ffffffff80140850>{specific_send_sig_info+2

       <ffffffff804472e5>{_spin_unlock_irqrestore+5} <ffffffff8014208a>{force_sig_info+186}
       <ffffffff804476ff>{do_general_protection+159} <ffffffff8010e308>{retint_signal+61}

Signed-off-by: Andrea Arcangeli <andrea@suse.de>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:22 -08:00
Paul Jackson
68860ec10b [PATCH] cpusets: automatic numa mempolicy rebinding
This patch automatically updates a tasks NUMA mempolicy when its cpuset
memory placement changes.  It does so within the context of the task,
without any need to support low level external mempolicy manipulation.

If a system is not using cpusets, or if running on a system with just the
root (all-encompassing) cpuset, then this remap is a no-op.  Only when a
task is moved between cpusets, or a cpusets memory placement is changed
does the following apply.  Otherwise, the main routine below,
rebind_policy() is not even called.

When mixing cpusets, scheduler affinity, and NUMA mempolicies, the
essential role of cpusets is to place jobs (several related tasks) on a set
of CPUs and Memory Nodes, the essential role of sched_setaffinity is to
manage a jobs processor placement within its allowed cpuset, and the
essential role of NUMA mempolicy (mbind, set_mempolicy) is to manage a jobs
memory placement within its allowed cpuset.

However, CPU affinity and NUMA memory placement are managed within the
kernel using absolute system wide numbering, not cpuset relative numbering.

This is ok until a job is migrated to a different cpuset, or what's the
same, a jobs cpuset is moved to different CPUs and Memory Nodes.

Then the CPU affinity and NUMA memory placement of the tasks in the job
need to be updated, to preserve their cpuset-relative position.  This can
be done for CPU affinity using sched_setaffinity() from user code, as one
task can modify anothers CPU affinity.  This cannot be done from an
external task for NUMA memory placement, as that can only be modified in
the context of the task using it.

However, it easy enough to remap a tasks NUMA mempolicy automatically when
a task is migrated, using the existing cpuset mechanism to trigger a
refresh of a tasks memory placement after its cpuset has changed.  All that
is needed is the old and new nodemask, and notice to the task that it needs
to rebind its mempolicy.  The tasks mems_allowed has the old mask, the
tasks cpuset has the new mask, and the existing
cpuset_update_current_mems_allowed() mechanism provides the notice.  The
bitmap/cpumask/nodemask remap operators provide the cpuset relative
calculations.

This patch leaves open a couple of issues:

 1) Updating vma and shmfs/tmpfs/hugetlbfs memory policies:

    These mempolicies may reference nodes outside of those allowed to
    the current task by its cpuset.  Tasks are migrated as part of jobs,
    which reside on what might be several cpusets in a subtree.  When such
    a job is migrated, all NUMA memory policy references to nodes within
    that cpuset subtree should be translated, and references to any nodes
    outside that subtree should be left untouched.  A future patch will
    provide the cpuset mechanism needed to mark such subtrees.  With that
    patch, we will be able to correctly migrate these other memory policies
    across a job migration.

 2) Updating cpuset, affinity and memory policies in user space:

    This is harder.  Any placement state stored in user space using
    system-wide numbering will be invalidated across a migration.  More
    work will be required to provide user code with a migration-safe means
    to manage its cpuset relative placement, while preserving the current
    API's that pass system wide numbers, not cpuset relative numbers across
    the kernel-user boundary.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:22 -08:00
Paul Jackson
18a19cb304 [PATCH] cpusets: simple rename
Add support for renaming cpusets.  Only allow simple rename of cpuset
directories in place.  Don't allow moving cpusets elsewhere in hierarchy or
renaming the special cpuset files in each cpuset directory.

The usefulness of this simple rename became apparent when developing task
migration facilities.  It allows building a second cpuset hierarchy using
new names and containing new CPUs and Memory Nodes, moving tasks from the
old to the new cpusets, removing the old cpusets, and then renaming the new
cpusets to be just like the old names, so that any knowledge that the tasks
had of their cpuset names will still be valid.

Leaf node cpusets can be migrated to other CPUs or Memory Nodes by just
updating their 'cpus' and 'mems' files, but because no cpuset can contain
CPUs or Nodes not in its parent cpuset, one cannot do this in a cpuset
hierarchy without first expanding all the non-leaf cpusets to contain the
union of both the old and new CPUs and Nodes, which would obfuscate the
one-to-one migration of a task from one cpuset to another required to
correctly migrate the physical page frames currently allocated to that
task.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:21 -08:00
Paul Jackson
053199edf5 [PATCH] cpusets: dual semaphore locking overhaul
Overhaul cpuset locking.  Replace single semaphore with two semaphores.

The suggestion to use two locks was made by Roman Zippel.

Both locks are global.  Code that wants to modify cpusets must first
acquire the exclusive manage_sem, which allows them read-only access to
cpusets, and holds off other would-be modifiers.  Before making actual
changes, the second semaphore, callback_sem must be acquired as well.  Code
that needs only to query cpusets must acquire callback_sem, which is also a
global exclusive lock.

The earlier problems with double tripping are avoided, because it is
allowed for holders of manage_sem to nest the second callback_sem lock, and
only callback_sem is needed by code called from within __alloc_pages(),
where the double tripping had been possible.

This is not quite the same as a normal read/write semaphore, because
obtaining read-only access with intent to change must hold off other such
attempts, while allowing read-only access w/o such intention.  Changing
cpusets involves several related checks and changes, which must be done
while allowing read-only queries (to avoid the double trip), but while
ensuring nothing changes (holding off other would be modifiers.)

This overhaul of cpuset locking also makes careful use of task_lock() to
guard access to the task->cpuset pointer, closing a couple of race
conditions noticed while reading this code (thanks, Roman).  I've never
seen these races fail in any use or test.

See further the comments in the code.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:21 -08:00
Paul Jackson
5aa15b5f27 [PATCH] cpusets: remove depth counted locking hack
Remove a rather hackish depth counter on cpuset locking.  The depth counter
was avoiding a possible double trip on the global cpuset_sem semaphore.  It
worked, but now an improved version of cpuset locking is available, to come
in the next patch, using two global semaphores.

This patch reverses "cpuset semaphore depth check deadlock fix"

The kernel still works, even after this patch, except for some rare and
difficult to reproduce race conditions when agressively creating and
destroying cpusets marked with the notify_on_release option, on very large
systems.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:21 -08:00
Paul Jackson
f35f31d7ed [PATCH] cpuset cleanup
Remove one more useless line from cpuset_common_file_read().

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:21 -08:00
Oleg Nesterov
4eb9af2a8a [PATCH] posix-timers: use schedule_timeout() in common_nsleep()
common_nsleep() reimplements schedule_timeout_interruptible() for unknown
reason.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:20 -08:00
Vadim Lobanov
6dd69f1061 [PATCH] Unify sys_tkill() and sys_tgkill()
The majority of the sys_tkill() and sys_tgkill() function code is
duplicated between the two of them.  This patch pulls the duplication out
into a separate function -- do_tkill() -- and lets sys_tkill() and
sys_tgkill() be simple wrappers around it.  This should make it easier to
maintain in light of future changes.

Signed-off-by: Vadim Lobanov <vlobanov@speakeasy.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:19 -08:00
Oleg Nesterov
19a4fcb531 [PATCH] kill sigqueue->lock
This lock is used in sigqueue_free(), but it is always equal to
current->sighand->siglock, so we don't need to keep it in the struct
sigqueue.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:19 -08:00
Andrew Morton
dfc4f94d2f [PATCH] remove timer debug field
Remove timer_list.magic and associated debugging code.

I originally added this when a spinlock was added to timer_list - this meant
that an all-zeroes timer became illegal and init_timer() was required.

That spinlock isn't even there any more, although timer.base must now be
initialised.

I'll keep this debugging code in -mm.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:18 -08:00
Christoph Lameter
89ada67917 [PATCH] Use alloc_percpu to allocate workqueues locally
This patch makes the workqueus use alloc_percpu instead of an array.  The
workqueues are placed on nodes local to each processor.

The workqueue structure can grow to a significant size on a system with
lots of processors if this patch is not applied.  64 bit architectures with
all debugging features enabled and configured for 512 processors will not
be able to boot without this patch.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:18 -08:00
Andrew Morton
a5a0d52c73 [PATCH] ntp whitespace cleanup
Fix bizarre 4-space coding style in the NTP code.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:18 -08:00
john stultz
1bb34a4127 [PATCH] NTP shift_right cleanup
Create a macro shift_right() that avoids the numerous ugly conditionals in the
NTP code that look like:

        if(a < 0)
                b = -(-a >> shift);
        else
                b = a >> shift;

Replacing it with:

        b = shift_right(a, shift);

This should have zero effect on the logic, however it should probably have
a bit of testing just to be sure.

Also replace open-coded min/max with the macros.

Signed-off-by : John Stultz <johnstul@us.ibm.com>

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:18 -08:00
Alan Stern
61e1a9ea4b [PATCH] Add kthread_stop_sem()
Enhance the kthread API by adding kthread_stop_sem, for use in stopping
threads that spend their idle time waiting on a semaphore.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:17 -08:00
Oleg Nesterov
a8db2db1e6 [PATCH] introduce setup_timer() helper
Every user of init_timer() also needs to initialize ->function and ->data
fields.  This patch adds a simple setup_timer() helper for that.

The schedule_timeout() is patched as an example of usage.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:17 -08:00
Shaohua Li
eb9289eb20 [PATCH] introduce .valid callback for pm_ops
Add pm_ops.valid callback, so only the available pm states show in
/sys/power/state.  And this also makes an earlier states error report at
enter_state before we do actual suspend/resume.

Signed-off-by: Shaohua Li<shaohua.li@intel.com>
Acked-by: Pavel Machek<pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:15 -08:00
Rafael J. Wysocki
0245b3e787 [PATCH] swsusp: two simplifications
The following patch simplifies the progress meter in disk.c:free_some_memory()
and makes disk.c:pm_suspend_disk() call device_resume() explicitly in the
suspend path.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:15 -08:00
Rafael J. Wysocki
2e32a43efd [PATCH] swsusp: get rid of unnecessary wrapper function
The following patch merges two functions in a trivial way.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:15 -08:00
Pavel Machek
de491861e1 [PATCH] swsusp: cleanups
Reduce number of ifdefs somehow, and fix whitespace a bit.  No real code
changes.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:14 -08:00
Pavel Machek
96bc7aec20 [PATCH] swsusp: remove unneccessary includes
Cleanup comments and remove unneccessary includes.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:14 -08:00
Rafael J. Wysocki
2c1b4a5ca4 [PATCH] swsusp: rework memory freeing on resume
The following patch makes swsusp use the PG_nosave and PG_nosave_free flags to
mark pages that should be freed in case of an error during resume.

This allows us to simplify the code and to use swsusp_free() in all of the
swsusp's resume error paths, which makes them actually work.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:14 -08:00
Rafael J. Wysocki
a0f496517f [PATCH] swsusp: reduce the use of global variables
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:14 -08:00
Rafael J. Wysocki
25761b6eb7 [PATCH] swsusp: move snapshot functionality to separate file
The following patch moves the functionality of swsusp related to creating and
handling the snapshot of memory to a separate file, snapshot.c

This should enable us to untangle the code in the future and eventually to
implement some parts of swsusp.c in the user space.

The patch does not change the code.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:14 -08:00
Rafael J. Wysocki
351619baf9 [PATCH] swsusp: rework image freeing
The following patch makes swsusp use PG_nosave and PG_nosave_free flags to
mark pages that should be freed after the state of the system has been
restored from the image (or in case of an error during suspend).

This allows us to avoid storing metadata in swap twice and to reduce the
amount of memory needed by swsusp.  Additionally, it allows us to simplify
the code by removing a couple of functions that are no longer necessary.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:14 -08:00
Ashok Raj
c32b6b8e52 [PATCH] create and destroy cpufreq sysfs entries based on cpu notifiers
cpufreq entries in sysfs should only be populated when CPU is online state.
 When we either boot with maxcpus=x and then boot the other cpus by echoing
to sysfs online file, these entries should be created and destroyed when
CPU_DEAD is notified.  Same treatement as cache entries under sysfs.

We place the processor in the lowest frequency, so hw managed P-State
transitions can still work on the other threads to save power.

Primary goal was to just make these directories appear/disapper dynamically.

There is one in this patch i had to do, which i really dont like myself but
probably best if someone handling the cpufreq infrastructure could give
this code right treatment if this is not acceptable.  I guess its probably
good for the first cut.

- Converting lock_cpu_hotplug()/unlock_cpu_hotplug() to disable/enable preempt.
  The locking was smack in the middle of the notification path, when the
  hotplug is already holding the lock. I tried another solution to avoid this
  so avoid taking locks if we know we are from notification path. The solution
  was getting very ugly and i decided this was probably good for this iteration
  until someone who understands cpufreq could do a better job than me.

(akpm: export cpucontrol to GPL modules: drivers/cpufreq/cpufreq_stats.c now
does lock_cpu_hotplug())

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Zwane Mwaikambo <zwane@holomorphy.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:14 -08:00
Brian Gerst
4276d32260 [PATCH] Remove redundant configs.o
Since CONFIG_IKCONFIG_PROC already depends on CONFIG_IKCONFIG, adding
configs.o again is redundant.

Signed-off-by: Brian Gerst <bgerst@didntduck.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:10 -08:00
Hugh Dickins
4c21e2f244 [PATCH] mm: split page table lock
Christoph Lameter demonstrated very poor scalability on the SGI 512-way, with
a many-threaded application which concurrently initializes different parts of
a large anonymous area.

This patch corrects that, by using a separate spinlock per page table page, to
guard the page table entries in that page, instead of using the mm's single
page_table_lock.  (But even then, page_table_lock is still used to guard page
table allocation, and anon_vma allocation.)

In this implementation, the spinlock is tucked inside the struct page of the
page table page: with a BUILD_BUG_ON in case it overflows - which it would in
the case of 32-bit PA-RISC with spinlock debugging enabled.

Splitting the lock is not quite for free: another cacheline access.  Ideally,
I suppose we would use split ptlock only for multi-threaded processes on
multi-cpu machines; but deciding that dynamically would have its own costs.
So for now enable it by config, at some number of cpus - since the Kconfig
language doesn't support inequalities, let preprocessor compare that with
NR_CPUS.  But I don't think it's worth being user-configurable: for good
testing of both split and unsplit configs, split now at 4 cpus, and perhaps
change that to 8 later.

There is a benefit even for singly threaded processes: kswapd can be attacking
one part of the mm while another part is busy faulting.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:42 -07:00
Hugh Dickins
deceb6cd17 [PATCH] mm: follow_page with inner ptlock
Final step in pushing down common core's page_table_lock.  follow_page no
longer wants caller to hold page_table_lock, uses pte_offset_map_lock itself;
and so no page_table_lock is taken in get_user_pages itself.

But get_user_pages (and get_futex_key) do then need follow_page to pin the
page for them: take Daniel's suggestion of bitflags to follow_page.

Need one for WRITE, another for TOUCH (it was the accessed flag before:
vanished along with check_user_page_readable, but surely get_numa_maps is
wrong to mark every page it finds as accessed), another for GET.

And another, ANON to dispose of untouched_anonymous_page: it seems silly for
that to descend a second time, let follow_page observe if there was no page
table and return ZERO_PAGE if so.  Fix minor bug in that: check VM_LOCKED -
make_pages_present ought to make readonly anonymous present.

Give get_numa_maps a cond_resched while we're there.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:41 -07:00
Hugh Dickins
c74df32c72 [PATCH] mm: ptd_alloc take ptlock
Second step in pushing down the page_table_lock.  Remove the temporary
bridging hack from __pud_alloc, __pmd_alloc, __pte_alloc: expect callers not
to hold page_table_lock, whether it's on init_mm or a user mm; take
page_table_lock internally to check if a racing task already allocated.

Convert their callers from common code.  But avoid coming back to change them
again later: instead of moving the spin_lock(&mm->page_table_lock) down,
switch over to new macros pte_alloc_map_lock and pte_unmap_unlock, which
encapsulate the mapping+locking and unlocking+unmapping together, and in the
end may use alternatives to the mm page_table_lock itself.

These callers all hold mmap_sem (some exclusively, some not), so at no level
can a page table be whipped away from beneath them; and pte_alloc uses the
"atomic" pmd_present to test whether it needs to allocate.  It appears that on
all arches we can safely descend without page_table_lock.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:40 -07:00
Hugh Dickins
365e9c87a9 [PATCH] mm: update_hiwaters just in time
update_mem_hiwater has attracted various criticisms, in particular from those
concerned with mm scalability.  Originally it was called whenever rss or
total_vm got raised.  Then many of those callsites were replaced by a timer
tick call from account_system_time.  Now Frank van Maarseveen reports that to
be found inadequate.  How about this?  Works for Frank.

Replace update_mem_hiwater, a poor combination of two unrelated ops, by macros
update_hiwater_rss and update_hiwater_vm.  Don't attempt to keep
mm->hiwater_rss up to date at timer tick, nor every time we raise rss (usually
by 1): those are hot paths.  Do the opposite, update only when about to lower
rss (usually by many), or just before final accounting in do_exit.  Handle
mm->hiwater_vm in the same way, though it's much less of an issue.  Demand
that whoever collects these hiwater statistics do the work of taking the
maximum with rss or total_vm.

And there has been no collector of these hiwater statistics in the tree.  The
new convention needs an example, so match Frank's usage by adding a VmPeak
line above VmSize to /proc/<pid>/status, and also a VmHWM line above VmRSS
(High-Water-Mark or High-Water-Memory).

There was a particular anomaly during mremap move, that hiwater_vm might be
captured too high.  A fleeting such anomaly remains, but it's quickly
corrected now, whereas before it would stick.

What locking?  None: if the app is racy then these statistics will be racy,
it's not worth any overhead to make them exact.  But whenever it suits,
hiwater_vm is updated under exclusive mmap_sem, and hiwater_rss under
page_table_lock (for now) or with preemption disabled (later on): without
going to any trouble, minimize the time between reading current values and
updating, to minimize those occasions when a racing thread bumps a count up
and back down in between.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:39 -07:00
Nick Piggin
b5810039a5 [PATCH] core remove PageReserved
Remove PageReserved() calls from core code by tightening VM_RESERVED
handling in mm/ to cover PageReserved functionality.

PageReserved special casing is removed from get_page and put_page.

All setting and clearing of PageReserved is retained, and it is now flagged
in the page_alloc checks to help ensure we don't introduce any refcount
based freeing of Reserved pages.

MAP_PRIVATE, PROT_WRITE of VM_RESERVED regions is tentatively being
deprecated.  We never completely handled it correctly anyway, and is be
reintroduced in future if required (Hugh has a proof of concept).

Once PageReserved() calls are removed from kernel/power/swsusp.c, and all
arch/ and driver code, the Set and Clear calls, and the PG_reserved bit can
be trivially removed.

Last real user of PageReserved is swsusp, which uses PageReserved to
determine whether a struct page points to valid memory or not.  This still
needs to be addressed (a generic page_is_ram() should work).

A last caveat: the ZERO_PAGE is now refcounted and managed with rmap (and
thus mapcounted and count towards shared rss).  These writes to the struct
page could cause excessive cacheline bouncing on big systems.  There are a
number of ways this could be addressed if it is an issue.

Signed-off-by: Nick Piggin <npiggin@suse.de>

Refcount bug fix for filemap_xip.c

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:39 -07:00
Hugh Dickins
7ee7823250 [PATCH] mm: dup_mmap down new mmap_sem
One anomaly remains from when Andrea rationalized the responsibilities of
mmap_sem and page_table_lock: in dup_mmap we add vmas to the child holding its
page_table_lock, but not the mmap_sem which normally guards the vma list and
rbtree.  Which could be an issue for unuse_mm: though since it just walks down
the list (today with page_table_lock, tomorrow not), it's probably okay.  Will
need a memory barrier?  Oh, keep it simple, Nick and I agreed, no harm in
taking child's mmap_sem here.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:38 -07:00
Hugh Dickins
fd3e42fcc8 [PATCH] mm: dup_mmap use oldmm more
Use the parent's oldmm throughout dup_mmap, instead of perversely going back
to current->mm.  (Can you hear the sigh of relief from those mpnts?  Usually I
squash them, but not today.)

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:38 -07:00
Hugh Dickins
4294621f41 [PATCH] mm: rss = file_rss + anon_rss
I was lazy when we added anon_rss, and chose to change as few places as
possible.  So currently each anonymous page has to be counted twice, in rss
and in anon_rss.  Which won't be so good if those are atomic counts in some
configurations.

Change that around: keep file_rss and anon_rss separately, and add them
together (with get_mm_rss macro) when the total is needed - reading two
atomics is much cheaper than updating two atomics.  And update anon_rss
upfront, typically in memory.c, not tucked away in page_add_anon_rmap.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:38 -07:00
Hugh Dickins
404351e67a [PATCH] mm: mm_init set_mm_counters
How is anon_rss initialized?  In dup_mmap, and by mm_alloc's memset; but
that's not so good if an mm_counter_t is a special type.  And how is rss
initialized?  By set_mm_counter, all over the place.  Come on, we just need to
initialize them both at once by set_mm_counter in mm_init (which follows the
memcpy when forking).

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:38 -07:00
Hugh Dickins
ab50b8ed81 [PATCH] mm: vm_stat_account unshackled
The original vm_stat_account has fallen into disuse, with only one user, and
only one user of vm_stat_unaccount.  It's easier to keep track if we convert
them all to __vm_stat_account, then free it from its __shackles.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:37 -07:00
YOSHIFUJI Hideaki
4b8f573b5d [PATCH] TIMERS: add missing compensation for HZ == 250
Add missing compensation for (HZ == 250) != (1 << SHIFT_HZ) in
second_overflow().

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:35 -07:00
Al Viro
943eae0314 [PATCH] missing exports of do_settimeofday() variants
frv, sh64, ia64 and sparc64 do not have do_settimeofday() exported (the
last two are using variant in kernel/time.c).  Exports added to match
the rest of architectures.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 10:35:07 -07:00
Oleg Nesterov
8d027de54c [PATCH] fix ->signal->live leak in copy_process()
exit_signal() (called from copy_process's error path) should decrement
->signal->live, otherwise forking process will miss 'group_dead' in
do_exit().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 10:28:13 -07:00
Al Viro
9796fdd829 [PATCH] gfp_t: kernel/*
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-28 08:16:49 -07:00
Paul Mackerras
4542437679 Merge in v2.6.14 by hand 2005-10-28 13:38:53 +10:00
Roland McGrath
72ab373a56 [PATCH] Yet more posix-cpu-timer fixes
This just makes sure that a thread's expiry times can't get reset after
it clears them in do_exit.

This is what allowed us to re-introduce the stricter BUG_ON() check in
a362f463a6.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-27 09:08:43 -07:00
Linus Torvalds
a362f463a6 Revert "remove false BUG_ON() from run_posix_cpu_timers()"
This reverts commit 3de463c7d9.

Roland has another patch that allows us to leave the BUG_ON() in place
by just making sure that the condition it tests for really is always
true.

That goes in next.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-27 09:07:33 -07:00
Oleg Nesterov
7a4ed937aa [PATCH] Fix cpu timers expiration time
There's a silly off-by-one error in the code that updates the expiration
of posix CPU timers, causing them to not be properly updated when they
hit exactly on their expiration time (which should be the normal case).

This causes them to then fire immediately again, and only _then_ get
properly updated.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-26 15:21:14 -07:00
Linus Torvalds
70ab81c2ed posix cpu timers: fix timer ordering
Pointed out by Oleg Nesterov, who has been walking over the code
forwards and backwards.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-26 11:23:06 -07:00
Andrew Morton
bb32051532 [PATCH] export cpu_online_map
With CONFIG_SMP=n:

*** Warning: "cpu_online_map" [drivers/firmware/dcdbas.ko] undefined!

due to set_cpus_allowed().

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-26 10:39:43 -07:00
Oleg Nesterov
a69ac4a78d [PATCH] posix-timers: fix posix_cpu_timer_set() vs run_posix_cpu_timers() race
This might be harmless, but looks like a race from code inspection (I
was unable to trigger it).  I must admit, I don't understand why we
can't return TIMER_RETRY after 'spin_unlock(&p->sighand->siglock)'
without doing bump_cpu_timer(), but this is what original code does.

posix_cpu_timer_set:

	read_lock(&tasklist_lock);

	spin_lock(&p->sighand->siglock);
	list_del_init(&timer->it.cpu.entry);
	spin_unlock(&p->sighand->siglock);

We are probaly deleting the timer from run_posix_cpu_timers's 'firing'
local list_head while run_posix_cpu_timers() does list_for_each_safe.

Various bad things can happen, for example we can just delete this timer
so that list_for_each() will not notice it and run_posix_cpu_timers()
will not reset '->firing' flag. In that case,

	....

	if (timer->it.cpu.firing) {
		read_unlock(&tasklist_lock);
		timer->it.cpu.firing = -1;
		return TIMER_RETRY;
	}

sys_timer_settime() goes to 'retry:', calls posix_cpu_timer_set() again,
it returns TIMER_RETRY ...

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-24 08:13:14 -07:00
Oleg Nesterov
ca531a0a5e [PATCH] posix-timers: exit path cleanup
No need to rebalance when task exited

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-24 08:12:35 -07:00
Oleg Nesterov
3de463c7d9 [PATCH] posix-timers: remove false BUG_ON() from run_posix_cpu_timers()
do_exit() clears ->it_##clock##_expires, but nothing prevents
another cpu to attach the timer to exiting process after that.

After exit_notify() does 'write_unlock_irq(&tasklist_lock)' and
before do_exit() calls 'schedule() local timer interrupt can find
tsk->exit_state != 0. If that state was EXIT_DEAD (or another cpu
does sys_wait4) interrupted task has ->signal == NULL.

At this moment exiting task has no pending cpu timers, they were cleaned
up in __exit_signal()->posix_cpu_timers_exit{,_group}(), so we can just
return from irq.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-24 08:12:35 -07:00
Oleg Nesterov
108150ea78 [PATCH] posix-timers: fix cleanup_timers() and run_posix_cpu_timers() races
1. cleanup_timers() sets timer->task = NULL under tasklist + ->sighand locks.
   That means that this code in posix_cpu_timer_del() and posix_cpu_timer_set()

   		lock_timer(timer);
		if (timer->task == NULL)
			return;
		read_lock(tasklist);
		put_task_struct(timer->task)

   is racy. With this patch timer->task modified and accounted only under
   timer->it_lock. Sadly, this means that dead task_struct won't be freed
   until timer deleted or armed.

2. run_posix_cpu_timers() collects expired timers into local list under
   tasklist + ->sighand again. That means that posix_cpu_timer_del()
   should check timer->it.cpu.firing under these locks too.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-24 08:12:35 -07:00
Linus Torvalds
e80eda94d3 Posix timers: limit number of timers firing at once
Bursty timers aren't good for anybody, very much including latency for
other programs when we trigger lots of timers in interrupt context.  So
set a random limit, after which we'll handle the rest on the next timer
tick.

Noted by Oleg Nesterov <oleg@tv-sign.ru>

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-23 10:02:50 -07:00
Paul Mackerras
985990137e Merge changes from linux-2.6 by hand 2005-10-22 16:51:34 +10:00
Roland McGrath
25f407f0b6 [PATCH] Call exit_itimers from do_exit, not __exit_signal
When I originally moved exit_itimers into __exit_signal, that was the only
place where we could reliably know it was the last thread in the group
dying, without races.  Since then we've gotten the signal_struct.live
counter, and do_exit can reliably do group-wide cleanup work.

This patch moves the call to do_exit, where it's made without locks.  This
avoids the deadlock issues that the old __exit_signal code's comment talks
about, and the one that Oleg found recently with process CPU timers.

[ This replaces e03d13e985, which is why
  it was just reverted. ]

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-21 15:38:08 -07:00
Linus Torvalds
9465bee863 Revert "Fix cpu timers exit deadlock and races"
Revert commit e03d13e985, to be replaced
by a much nicer fix from Roland.
2005-10-21 15:36:00 -07:00
Alan Stern
d1209d049b [PATCH] Threads shouldn't inherit PF_NOFREEZE
The PF_NOFREEZE process flag should not be inherited when a thread is
forked.  This patch (as585) removes the flag from the child.

This problem is starting to show up more and more as drivers turn to the
kthread API instead of using kernel_thread().  As a result, their kernel
threads are now children of the kthread worker instead of modprobe, and
they inherit the PF_NOFREEZE flag.  This can cause problems during system
suspend; the kernel threads are not getting frozen as they ought to be.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-19 23:04:31 -07:00
Roland McGrath
e03d13e985 [PATCH] Fix cpu timers exit deadlock and races
Oleg Nesterov reported an SMP deadlock.  If there is a running timer
tracking a different process's CPU time clock when the process owning
the timer exits, we deadlock on tasklist_lock in posix_cpu_timer_del via
exit_itimers.

That code was using tasklist_lock to check for a race with __exit_signal
being called on the timer-target task and clearing its ->signal.
However, there is actually no such race.  __exit_signal will have called
posix_cpu_timers_exit and posix_cpu_timers_exit_group before it does
that.  Those will clear those k_itimer's association with the dying
task, so posix_cpu_timer_del will return early and never reach the code
in question.

In addition, posix_cpu_timer_del called from exit_itimers during execve
or directly from timer_delete in the process owning the timer can race
with an exiting timer-target task to cause a double put on timer-target
task struct.  Make sure we always access cpu_timers lists with sighand
lock held.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-19 23:02:01 -07:00
Eric Dumazet
5ee832dbc6 [PATCH] rcu: keep rcu callback event counter
This makes call_rcu() keep track of how many events there are on the RCU
list, and cause a reschedule event when the list gets too long.

This helps keep RCU event lists down.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-17 15:27:58 -07:00
Oleg Nesterov
47d6b08334 [PATCH] posix-timers: fix task accounting
Make sure we release the task struct properly when releasing pending
timers.

release_task() does write_lock_irq(&tasklist_lock), so it can't race
with run_posix_cpu_timers() on any cpu.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-17 15:00:00 -07:00
Linus Torvalds
2cc78eb52b Increase default RCU batching sharply
Dipankar made RCU limit the batch size to improve latency, but that
approach is unworkable: it can cause the RCU queues to grow without
bounds, since the batch limiter ended up limiting the callbacks.

So make the limit much higher, and start planning on instead limiting
the batch size by doing RCU callbacks more often if the queue looks like
it might be growing too long.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-17 09:10:15 -07:00
Takashi Iwai
c6ecf7ed31 [PATCH] Add missing export of getnstimeofday()
Adds the missing EXPORT_SYMBOL_GPL for getnstimeofday() when
CONFIG_TIME_INTERPOLATION isn't set.  Needed by drivers/char/mmtimer.c

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-14 17:10:12 -07:00
Paul Mackerras
b6ec995a21 Merge from Linus' tree 2005-10-12 14:43:32 +10:00
Harald Welte
46113830a1 [PATCH] Fix signal sending in usbdevio on async URB completion
If a process issues an URB from userspace and (starts to) terminate
before the URB comes back, we run into the issue described above.  This
is because the urb saves a pointer to "current" when it is posted to the
device, but there's no guarantee that this pointer is still valid
afterwards.

In fact, there are three separate issues:

1) the pointer to "current" can become invalid, since the task could be
   completely gone when the URB completion comes back from the device.

2) Even if the saved task pointer is still pointing to a valid task_struct,
   task_struct->sighand could have gone meanwhile.

3) Even if the process is perfectly fine, permissions may have changed,
   and we can no longer send it a signal.

So what we do instead, is to save the PID and uid's of the process, and
introduce a new kill_proc_info_as_uid() function.

Signed-off-by: Harald Welte <laforge@gnumonks.org>
[ Fixed up types and added symbol exports ]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 16:16:33 -07:00
Rafael J. Wysocki
3dd083255d [PATCH] x86_64: Set up safe page tables during resume
The following patch makes swsusp avoid the possible temporary corruption
of page translation tables during resume on x86-64.  This is achieved by
creating a copy of the relevant page tables that will not be modified by
swsusp and can be safely used by it on resume.

The problem is that during resume on x86-64 swsusp may temporarily
corrupt the page tables used for the direct mapping of RAM.  If that
happens, a page fault occurs and cannot be handled properly, which leads
to the solid hang of the affected system.  This leads to the loss of the
system's state from before suspend and may result in the loss of data or
the corruption of filesystems, so it is a serious issue.  Also, it
appears to happen quite often (for me, as often as 50% of the time).

The problem is related to the fact that (at least) one of the PMD
entries used in the direct memory mapping (starting at PAGE_OFFSET)
points to a page table the physical address of which is much greater
than the physical address of the PMD entry itself.  Moreover,
unfortunately, the physical address of the page table before suspend
(i.e.  the one stored in the suspend image) happens to be different to
the physical address of the corresponding page table used during resume
(i.e.  the one that is valid right before swsusp_arch_resume() in
arch/x86_64/kernel/suspend_asm.S is executed).  Thus while the image is
restored, the "offending" PMD entry gets overwritten, so it does not
point to the right physical address any more (i.e.  there's no page
table at the address pointed to by it, because it points to the address
the page table has been at during suspend).  Consequently, if the PMD
entry is used later on, and it _is_ used in the process of copying the
image pages, a page fault occurs, but it cannot be handled in the normal
way and the system hangs.

In principle we can call create_resume_mapping() from
swsusp_arch_resume() (ie.  from suspend_asm.S), but then the memory
allocations in create_resume_mapping(), resume_pud_mapping(), and
resume_pmd_mapping() must be made carefully so that we use _only_
NosaveFree pages in them (the other pages are overwritten by the loop in
swsusp_arch_resume()).  Additionally, we are in atomic context at that
time, so we cannot use GFP_KERNEL.  Moreover, if one of the allocations
fails, we should free all of the allocated pages, so we need to trace
them somehow.

All of this is done in the appended patch, except that the functions
populating the page tables are located in arch/x86_64/kernel/suspend.c
rather than in init.c.  It may be done in a more elegan way in the
future, with the help of some swsusp patches that are in the works now.

[AK: move some externs into headers, renamed a function]

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:36:46 -07:00
Al Viro
dd0fc66fb3 [PATCH] gfp flags annotations - part 1
- added typedef unsigned int __nocast gfp_t;

 - replaced __nocast uses for gfp flags with gfp_t - it gives exactly
   the same warnings as far as sparse is concerned, doesn't change
   generated code (from gcc point of view we replaced unsigned int with
   typedef) and documents what's going on far better.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 15:00:57 -07:00