Impact: new ftrace_graph_stop function
While developing more features of function graph, I hit a bug that
caused the WARN_ON to trigger in the prepare_ftrace_return function.
Well, it was hard for me to find out that was happening because the
bug would not print, it would just cause a hard lockup or reboot.
The reason is that it is not safe to call printk from this function.
Looking further, I also found that it calls unregister_ftrace_graph,
which grabs a mutex and calls kstop machine. This would definitely
lock the box up if it were to trigger.
This patch adds a fast and safe ftrace_graph_stop() which will
stop the function tracer. Then it is safe to call the WARN ON.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: consistency change for function graph
This patch makes function graph record the mcount caller address
the same way the function tracer does.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
There exists macros for x86 asm to handle x86_64 and i386.
This patch updates function graph asm to use them.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Merge x86/dumpstack into tracing/ftrace because upcoming ftrace changes
depend on cleanups already in x86/dumpstack.
Also merge to latest upstream -rc.
Impact: extend and enable the function graph tracer to 64-bit x86
This patch implements the support for function graph tracer under x86-64.
Both static and dynamic tracing are supported.
This causes some small CPP conditional asm on arch/x86/kernel/ftrace.c I
wanted to use probe_kernel_read/write to make the return address
saving/patching code more generic but it causes tracing recursion.
That would be perhaps useful to implement a notrace version of these
function for other archs ports.
Note that arch/x86/process_64.c is not traced, as in X86-32. I first
thought __switch_to() was responsible of crashes during tracing because I
believed current task were changed inside but that's actually not the
case (actually yes, but not the "current" pointer).
So I will have to investigate to find the functions that harm here, to
enable tracing of the other functions inside (but there is no issue at
this time, while process_64.c stays out of -pg flags).
A little possible race condition is fixed inside this patch too. When the
tracer allocate a return stack dynamically, the current depth is not
initialized before but after. An interrupt could occur at this time and,
after seeing that the return stack is allocated, the tracer could try to
trace it with a random uninitialized depth. It's a prevention, even if I
hadn't problems with it.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
irq.h: fix missing/extra kernel-doc
genirq: __irq_set_trigger: change pr_warning to pr_debug
irq: fix typo
x86: apic honour irq affinity which was set in early boot
genirq: fix the affinity setting in setup_irq
genirq: keep affinities set from userspace across free/request_irq()
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: always define DECLARE_PCI_UNMAP* macros
x86: fixup config space size of CPU functions for AMD family 11h
x86, bts: fix wrmsr and spinlock over kmalloc
x86, pebs: fix PEBS record size configuration
x86, bts: turn macro into static inline function
x86, bts: exclude ds.c from build when disabled
arch/x86/kernel/pci-calgary_64.c: change simple_strtol to simple_strtoul
x86: use limited register constraint for setnz
xen: pin correct PGD on suspend
x86: revert irq number limitation
x86: fixing __cpuinit/__init tangle, xsave_cntxt_init()
x86: fix __cpuinit/__init tangle in init_thread_xstate()
oprofile: fix an overflow in ppro code
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
[CPUFREQ] powernow-k8: ignore out-of-range PstateStatus value
[CPUFREQ] Documentation: Add Blackfin to list of supported processors
All architectures now use the generic compat_sys_ptrace, as should every
new architecture that needs 32bit compat (if we'll ever get another).
Remove the now superflous __ARCH_WANT_COMPAT_SYS_PTRACE define, and also
kill a comment about __ARCH_SYS_PTRACE that was added after
__ARCH_SYS_PTRACE was already gone.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
... so get xen-ops.h in agreement with xen/smp.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: fix boot crash on AMD IOMMU if CONFIG_GART_IOMMU is off
Currently these macros evaluate to a no-op except the kernel is compiled
with GART or Calgary support. But we also need these macros when we have
SWIOTLB, VT-d or AMD IOMMU in the kernel. Since we always compile at
least with SWIOTLB we can define these macros always.
This patch is also for stable backport for the same reason the SWIOTLB
default selection patch is.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: new "power-tracer" ftrace plugin
This patch adds a C/P-state ftrace plugin that will generate
detailed statistics about the C/P-states that are being used,
so that we can look at detailed decisions that the C/P-state
code is making, rather than the too high level "average"
that we have today.
An example way of using this is:
mount -t debugfs none /sys/kernel/debug
echo cstate > /sys/kernel/debug/tracing/current_tracer
echo 1 > /sys/kernel/debug/tracing/tracing_enabled
sleep 1
echo 0 > /sys/kernel/debug/tracing/tracing_enabled
cat /sys/kernel/debug/tracing/trace | perl scripts/trace/cstate.pl > out.svg
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: more efficient code for ftrace graph tracer
This patch uses the dynamic patching, when available, to patch
the function graph code into the kernel.
This patch will ease the way for letting both function tracing
and function graph tracing run together.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: extend allowed configuration space access on 11h CPUs from 256 to 4K
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: feature
This patch sets a C-like output for the function graph tracing.
For this aim, we now call two handler for each function: one on the entry
and one other on return. This way we can draw a well-ordered call stack.
The pid of the previous trace is loosely stored to be compared against
the one of the current trace to see if there were a context switch.
Without this little feature, the call tree would seem broken at
some locations.
We could use the sched_tracer to capture these sched_events but this
way of processing is much more simpler.
2 spaces have been chosen for indentation to fit the screen while deep
calls. The time of execution in nanosecs is printed just after closed
braces, it seems more easy this way to find the corresponding function.
If the time was printed as a first column, it would be not so easy to
find the corresponding function if it is called on a deep depth.
I plan to output the return value but on 32 bits CPU, the return value
can be 32 or 64, and its difficult to guess on which case we are.
I don't know what would be the better solution on X86-32: only print
eax (low-part) or even edx (high-part).
Actually it's thee same problem when a function return a 8 bits value, the
high part of eax could contain junk values...
Here is an example of trace:
sys_read() {
fget_light() {
} 526
vfs_read() {
rw_verify_area() {
security_file_permission() {
cap_file_permission() {
} 519
} 1564
} 2640
do_sync_read() {
pipe_read() {
__might_sleep() {
} 511
pipe_wait() {
prepare_to_wait() {
} 760
deactivate_task() {
dequeue_task() {
dequeue_task_fair() {
dequeue_entity() {
update_curr() {
update_min_vruntime() {
} 504
} 1587
clear_buddies() {
} 512
add_cfs_task_weight() {
} 519
update_min_vruntime() {
} 511
} 5602
dequeue_entity() {
update_curr() {
update_min_vruntime() {
} 496
} 1631
clear_buddies() {
} 496
update_min_vruntime() {
} 527
} 4580
hrtick_update() {
hrtick_start_fair() {
} 488
} 1489
} 13700
} 14949
} 16016
msecs_to_jiffies() {
} 496
put_prev_task_fair() {
} 504
pick_next_task_fair() {
} 489
pick_next_task_rt() {
} 496
pick_next_task_fair() {
} 489
pick_next_task_idle() {
} 489
------------8<---------- thread 4 ------------8<----------
finish_task_switch() {
} 1203
do_softirq() {
__do_softirq() {
__local_bh_disable() {
} 669
rcu_process_callbacks() {
__rcu_process_callbacks() {
cpu_quiet() {
rcu_start_batch() {
} 503
} 1647
} 3128
__rcu_process_callbacks() {
} 542
} 5362
_local_bh_enable() {
} 587
} 8880
} 9986
kthread_should_stop() {
} 669
deactivate_task() {
dequeue_task() {
dequeue_task_fair() {
dequeue_entity() {
update_curr() {
calc_delta_mine() {
} 511
update_min_vruntime() {
} 511
} 2813
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
This patch changes the name of the "return function tracer" into
function-graph-tracer which is a more suitable name for a tracing
which makes one able to retrieve the ordered call stack during
the code flow.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
A workaround for AMD CPU family 11h erratum 311 might cause that the
P-state Status Register shows a "current P-state" which is larger than
the "current P-state limit" in P-state Current Limit Register. For the
wrong P-state value there is no ACPI _PSS object defined and
powernow-k8/cpufreq can't determine the proper CPU frequency for that
state.
As a consequence this can cause a panic during boot (potentially with
all recent kernel versions -- at least I have reproduced it with
various 2.6.27 kernels and with the current .28 series), as an
example:
powernow-k8: Found 1 AMD Turion(tm)X2 Ultra DualCore Mobile ZM-82 processors (2 \
)
powernow-k8: 0 : pstate 0 (2200 MHz)
powernow-k8: 1 : pstate 1 (1100 MHz)
powernow-k8: 2 : pstate 2 (600 MHz)
BUG: unable to handle kernel paging request at ffff88086e7528b8
IP: [<ffffffff80486361>] cpufreq_stats_update+0x4a/0x5f
PGD 202063 PUD 0
Oops: 0002 [#1] SMP
last sysfs file:
CPU 1
Modules linked in:
Pid: 1, comm: swapper Not tainted 2.6.28-rc3-dirty #16
RIP: 0010:[<ffffffff80486361>] [<ffffffff80486361>] cpufreq_stats_update+0x4a/0\
f
Synaptics claims to have extended capabilities, but I'm not able to read them.<6\
6
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88006e7528c0
RDX: 00000000ffffffff RSI: ffff88006e54af00 RDI: ffffffff808f056c
RBP: 00000000fffee697 R08: 0000000000000003 R09: ffff88006e73f080
R10: 0000000000000001 R11: 00000000002191c0 R12: ffff88006fb83c10
R13: 00000000ffffffff R14: 0000000000000001 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88006fb50740(0000) knlGS:0000000000000000
Unable to initialize Synaptics hardware.
CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: ffff88086e7528b8 CR3: 0000000000201000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process swapper (pid: 1, threadinfo ffff88006fb82000, task ffff88006fb816d0)
Stack:
ffff88006e74da50 0000000000000000 ffff88006e54af00 ffffffff804863c7
ffff88006e74da50 0000000000000000 00000000ffffffff 0000000000000000
ffff88006fb83c10 ffffffff8024b46c ffffffff808f0560 ffff88006fb83c10
Call Trace:
[<ffffffff804863c7>] ? cpufreq_stat_notifier_trans+0x51/0x83
[<ffffffff8024b46c>] ? notifier_call_chain+0x29/0x4c
[<ffffffff8024b561>] ? __srcu_notifier_call_chain+0x46/0x61
[<ffffffff8048496d>] ? cpufreq_notify_transition+0x93/0xa9
[<ffffffff8021ab8d>] ? powernowk8_target+0x1e8/0x5f3
[<ffffffff80486687>] ? cpufreq_governor_performance+0x1b/0x20
[<ffffffff80484886>] ? __cpufreq_governor+0x71/0xa8
[<ffffffff80484b21>] ? __cpufreq_set_policy+0x101/0x13e
[<ffffffff80485bcd>] ? cpufreq_add_dev+0x3f0/0x4cd
[<ffffffff8048577a>] ? handle_update+0x0/0x8
[<ffffffff803c2062>] ? sysdev_driver_register+0xb6/0x10d
[<ffffffff8056592c>] ? powernowk8_init+0x0/0x7e
[<ffffffff8048604c>] ? cpufreq_register_driver+0x8f/0x140
[<ffffffff80209056>] ? _stext+0x56/0x14f
[<ffffffff802c2234>] ? proc_register+0x122/0x17d
[<ffffffff802c23a0>] ? create_proc_entry+0x73/0x8a
[<ffffffff8025c259>] ? register_irq_proc+0x92/0xaa
[<ffffffff8025c2c8>] ? init_irq_proc+0x57/0x69
[<ffffffff807fc85f>] ? kernel_init+0x116/0x169
[<ffffffff8020cc79>] ? child_rip+0xa/0x11
[<ffffffff807fc749>] ? kernel_init+0x0/0x169
[<ffffffff8020cc6f>] ? child_rip+0x0/0x11
Code: 05 c5 83 36 00 48 c7 c2 48 5d 86 80 48 8b 04 d8 48 8b 40 08 48 8b 34 02 48\
RIP [<ffffffff80486361>] cpufreq_stats_update+0x4a/0x5f
RSP <ffff88006fb83b20>
CR2: ffff88086e7528b8
---[ end trace 0678bac75e67a2f7 ]---
Kernel panic - not syncing: Attempted to kill init!
In short, aftereffect of the wrong P-state is that
cpufreq_stats_update() uses "-1" as index for some array in
cpufreq_stats_update (unsigned int cpu)
{
...
if (stat->time_in_state)
stat->time_in_state[stat->last_index] =
cputime64_add(stat->time_in_state[stat->last_index],
cputime_sub(cur_time, stat->last_time));
...
}
Fortunately, the wrong P-state value is returned only if the core is
in P-state 0. This fix solves the problem by detecting the
out-of-range P-state, ignoring it, and using "0" instead.
Cc: Mark Langsdorf <mark.langsdorf@amd.com>
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Impact: add new ftrace plugin
A prototype for a BTS ftrace plug-in.
The tracer collects branch trace in a cyclic buffer for each cpu.
The tracer is not configurable and the trace for each snapshot is
appended when doing cat /debug/tracing/trace.
This is a proof of concept that will be extended with future patches
to become a (hopefully) useful tool.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: restructure DS memory allocation to be done by the usage site of DS
Require pre-allocated buffers in ds.h.
Move the BTS buffer allocation for ptrace into ptrace.c.
The pointer to the allocated buffer is stored in the traced task's
task_struct together with the handle returned by ds_request_bts().
Removes memory accounting code.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: generalize the DS code to shared buffers
Change the in-kernel ds.h interface to identify the tracer via a
handle returned on ds_request_~().
Tracers used to be identified via their task_struct.
The changes are required to allow DS to be shared between different
tasks, which is needed for perfmon2 and for ftrace.
For ptrace, the handle is stored in the traced task's task_struct.
This should probably go into a (arch-specific) ptrace context some
time.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix sleeping-with-spinlock-held bugs/crashes
- Turn a wrmsr to write the DS_AREA MSR into a wrmsrl.
- Use irqsave variants of spinlocks.
- Do not allocate memory while holding spinlocks.
Reported-by: Stephane Eranian <eranian@googlemail.com>
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix DS hw enablement on 64-bit x86
Fix the PEBS record size in the DS configuration.
Reported-by: Stephane Eranian <eranian@googlemail.com>
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Replace a macro with a static inline function.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Move the CONFIG guard from the .c file into the makefile.
Reported-by: Andi Kleen <andi-suse@firstfloor.org>
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix theoretical option string parsing overflow
Since bridge is unsigned, it would seem better to use simple_strtoul that
simple_strtol.
A simplified version of the semantic patch that makes this change is as
follows: (http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@r2@
long e;
position p;
@@
e = simple_strtol@p(...)
@@
position p != r2.p;
type T;
T e;
@@
e =
- simple_strtol@p
+ simple_strtoul
(...)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: muli@il.ibm.com
Cc: jdmason@kudzu.us
Cc: discuss@x86-64.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: build fix with certain compilers
GCC can decide to use %dil when "r" is used, which is not valid for
setnz.
This bug was brought out by Stephen Rothwell's merging of the
branch tracer into linux-next.
[ Thanks to Uros Bizjak for recommending 'q' over 'Q' ]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix MSIx not enough irq numbers available regression
The manual revert of the sparse_irq patches missed to bring the number
of possible irqs back to the .27 status. This resulted in a regression
when two multichannel network cards were placed in a system with only
one IO_APIC - causing the networking driver to not have the right
IRQ and the device not coming up.
Remove the dynamic allocation logic leftovers and simply return
NR_IRQS in probe_nr_irqs() for now.
Fixes: http://lkml.org/lkml/2008/11/19/354
Reported-by: Jesper Dangaard Brouer <hawk@diku.dk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jesper Dangaard Brouer <hawk@diku.dk>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
User stack tracing is just implemented for x86, but it is not x86 specific.
Introduce a generic config flag, that is currently enabled only for x86.
When other arches implement it, they will have to
SELECT USER_STACKTRACE_SUPPORT.
Signed-off-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add new (default-off) tracing visualization feature
Usage example:
mount -t debugfs nodev /sys/kernel/debug
cd /sys/kernel/debug/tracing
echo userstacktrace >iter_ctrl
echo sched_switch >current_tracer
echo 1 >tracing_enabled
.... run application ...
echo 0 >tracing_enabled
Then read one of 'trace','latency_trace','trace_pipe'.
To get the best output you can compile your userspace programs with
frame pointers (at least glibc + the app you are tracing).
Signed-off-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: use deeper function tracing depth safely
Some tests showed that function return tracing needed a more deeper depth
of function calls. But it could be unsafe to store these return addresses
to the stack.
So these arrays will now be allocated dynamically into task_struct of current
only when the tracer is activated.
Typical scheme when tracer is activated:
- allocate a return stack for each task in global list.
- fork: allocate the return stack for the newly created task
- exit: free return stack of current
- idle init: same as fork
I chose a default depth of 50. I don't have overruns anymore.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When we migrate an interrupt from one CPU to another, we set the
move_in_progress flag and clean up the vectors later once they're not
being used. If you're unlucky and call destroy_irq() before the vectors
become un-used, the move_in_progress flag is never cleared, which causes
the interrupt to become unusable.
This was discovered by Jesse Brandeburg for whom it manifested as an
MSI-X device refusing to use MSI-X mode when the driver was unloaded
and reloaded repeatedly.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: uaccess_64: fix return value in __copy_from_user()
x86: quirk for reboot stalls on a Dell Optiplex 330
Annotate xsave_cntxt_init() as "can be called outside of __init".
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix incorrect __init annotation
This patch removes the following section mismatch warning. A patch set
was send previously (http://lkml.org/lkml/2008/11/10/407). But
introduce some other problem, reported by Rufus
(http://lkml.org/lkml/2008/11/11/46). Then Ingo Molnar suggest that,
it's best to remove __init from xsave_cntxt_init(void). Which is the
second patch in this series. Now, this one removes the following
warning.
WARNING: arch/x86/kernel/built-in.o(.cpuinit.text+0x2237): Section
mismatch in reference from the function cpu_init() to the function
.init.text:init_thread_xstate()
The function __cpuinit cpu_init() references
a function __init init_thread_xstate().
If init_thread_xstate is only used by cpu_init then
annotate init_thread_xstate with a matching annotation.
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86/numa' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: make NUMA on 32-bit depend on EXPERIMENTAL again
x86, hibernate: fix breakage on x86_32 with CONFIG_NUMA set
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: more general identifier for Phoenix BIOS
AMD IOMMU: check for next_bit also in unmapped area
AMD IOMMU: fix fullflush comparison length
AMD IOMMU: enable device isolation per default
AMD IOMMU: add parameter to disable device isolation
x86, PEBS/DS: fix code flow in ds_request()
x86: add rdtsc barrier to TSC sync check
xen: fix scrub_page()
x86: fix es7000 compiling
x86, bts: fix unlock problem in ds.c
x86, voyager: fix smp generic helper voyager breakage
x86: move iomap.h to the new include location
Introduce a new accept4() system call. The addition of this system call
matches analogous changes in 2.6.27 (dup3(), evenfd2(), signalfd4(),
inotify_init1(), epoll_create1(), pipe2()) which added new system calls
that differed from analogous traditional system calls in adding a flags
argument that can be used to access additional functionality.
The accept4() system call is exactly the same as accept(), except that
it adds a flags bit-mask argument. Two flags are initially implemented.
(Most of the new system calls in 2.6.27 also had both of these flags.)
SOCK_CLOEXEC causes the close-on-exec (FD_CLOEXEC) flag to be enabled
for the new file descriptor returned by accept4(). This is a useful
security feature to avoid leaking information in a multithreaded
program where one thread is doing an accept() at the same time as
another thread is doing a fork() plus exec(). More details here:
http://udrepper.livejournal.com/20407.html "Secure File Descriptor Handling",
Ulrich Drepper).
The other flag is SOCK_NONBLOCK, which causes the O_NONBLOCK flag
to be enabled on the new open file description created by accept4().
(This flag is merely a convenience, saving the use of additional calls
fcntl(F_GETFL) and fcntl (F_SETFL) to achieve the same result.
Here's a test program. Works on x86-32. Should work on x86-64, but
I (mtk) don't have a system to hand to test with.
It tests accept4() with each of the four possible combinations of
SOCK_CLOEXEC and SOCK_NONBLOCK set/clear in 'flags', and verifies
that the appropriate flags are set on the file descriptor/open file
description returned by accept4().
I tested Ulrich's patch in this thread by applying against 2.6.28-rc2,
and it passes according to my test program.
/* test_accept4.c
Copyright (C) 2008, Linux Foundation, written by Michael Kerrisk
<mtk.manpages@gmail.com>
Licensed under the GNU GPLv2 or later.
*/
#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#define PORT_NUM 33333
#define die(msg) do { perror(msg); exit(EXIT_FAILURE); } while (0)
/**********************************************************************/
/* The following is what we need until glibc gets a wrapper for
accept4() */
/* Flags for socket(), socketpair(), accept4() */
#ifndef SOCK_CLOEXEC
#define SOCK_CLOEXEC O_CLOEXEC
#endif
#ifndef SOCK_NONBLOCK
#define SOCK_NONBLOCK O_NONBLOCK
#endif
#ifdef __x86_64__
#define SYS_accept4 288
#elif __i386__
#define USE_SOCKETCALL 1
#define SYS_ACCEPT4 18
#else
#error "Sorry -- don't know the syscall # on this architecture"
#endif
static int
accept4(int fd, struct sockaddr *sockaddr, socklen_t *addrlen, int flags)
{
printf("Calling accept4(): flags = %x", flags);
if (flags != 0) {
printf(" (");
if (flags & SOCK_CLOEXEC)
printf("SOCK_CLOEXEC");
if ((flags & SOCK_CLOEXEC) && (flags & SOCK_NONBLOCK))
printf(" ");
if (flags & SOCK_NONBLOCK)
printf("SOCK_NONBLOCK");
printf(")");
}
printf("\n");
#if USE_SOCKETCALL
long args[6];
args[0] = fd;
args[1] = (long) sockaddr;
args[2] = (long) addrlen;
args[3] = flags;
return syscall(SYS_socketcall, SYS_ACCEPT4, args);
#else
return syscall(SYS_accept4, fd, sockaddr, addrlen, flags);
#endif
}
/**********************************************************************/
static int
do_test(int lfd, struct sockaddr_in *conn_addr,
int closeonexec_flag, int nonblock_flag)
{
int connfd, acceptfd;
int fdf, flf, fdf_pass, flf_pass;
struct sockaddr_in claddr;
socklen_t addrlen;
printf("=======================================\n");
connfd = socket(AF_INET, SOCK_STREAM, 0);
if (connfd == -1)
die("socket");
if (connect(connfd, (struct sockaddr *) conn_addr,
sizeof(struct sockaddr_in)) == -1)
die("connect");
addrlen = sizeof(struct sockaddr_in);
acceptfd = accept4(lfd, (struct sockaddr *) &claddr, &addrlen,
closeonexec_flag | nonblock_flag);
if (acceptfd == -1) {
perror("accept4()");
close(connfd);
return 0;
}
fdf = fcntl(acceptfd, F_GETFD);
if (fdf == -1)
die("fcntl:F_GETFD");
fdf_pass = ((fdf & FD_CLOEXEC) != 0) ==
((closeonexec_flag & SOCK_CLOEXEC) != 0);
printf("Close-on-exec flag is %sset (%s); ",
(fdf & FD_CLOEXEC) ? "" : "not ",
fdf_pass ? "OK" : "failed");
flf = fcntl(acceptfd, F_GETFL);
if (flf == -1)
die("fcntl:F_GETFD");
flf_pass = ((flf & O_NONBLOCK) != 0) ==
((nonblock_flag & SOCK_NONBLOCK) !=0);
printf("nonblock flag is %sset (%s)\n",
(flf & O_NONBLOCK) ? "" : "not ",
flf_pass ? "OK" : "failed");
close(acceptfd);
close(connfd);
printf("Test result: %s\n", (fdf_pass && flf_pass) ? "PASS" : "FAIL");
return fdf_pass && flf_pass;
}
static int
create_listening_socket(int port_num)
{
struct sockaddr_in svaddr;
int lfd;
int optval;
memset(&svaddr, 0, sizeof(struct sockaddr_in));
svaddr.sin_family = AF_INET;
svaddr.sin_addr.s_addr = htonl(INADDR_ANY);
svaddr.sin_port = htons(port_num);
lfd = socket(AF_INET, SOCK_STREAM, 0);
if (lfd == -1)
die("socket");
optval = 1;
if (setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &optval,
sizeof(optval)) == -1)
die("setsockopt");
if (bind(lfd, (struct sockaddr *) &svaddr,
sizeof(struct sockaddr_in)) == -1)
die("bind");
if (listen(lfd, 5) == -1)
die("listen");
return lfd;
}
int
main(int argc, char *argv[])
{
struct sockaddr_in conn_addr;
int lfd;
int port_num;
int passed;
passed = 1;
port_num = (argc > 1) ? atoi(argv[1]) : PORT_NUM;
memset(&conn_addr, 0, sizeof(struct sockaddr_in));
conn_addr.sin_family = AF_INET;
conn_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
conn_addr.sin_port = htons(port_num);
lfd = create_listening_socket(port_num);
if (!do_test(lfd, &conn_addr, 0, 0))
passed = 0;
if (!do_test(lfd, &conn_addr, SOCK_CLOEXEC, 0))
passed = 0;
if (!do_test(lfd, &conn_addr, 0, SOCK_NONBLOCK))
passed = 0;
if (!do_test(lfd, &conn_addr, SOCK_CLOEXEC, SOCK_NONBLOCK))
passed = 0;
close(lfd);
exit(passed ? EXIT_SUCCESS : EXIT_FAILURE);
}
[mtk.manpages@gmail.com: rewrote changelog, updated test program]
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Tested-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
