The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* master.kernel.org:/pub/scm/linux/kernel/git/sam/kbuild: (46 commits)
kbuild: remove obsoleted scripts/reference_* files
kbuild: fix make help & make *pkg
kconfig: fix time ordering of writes to .kconfig.d and include/linux/autoconf.h
Kconfig: remove the CONFIG_CC_ALIGN_* options
kbuild: add -fverbose-asm to i386 Makefile
kbuild: clean-up genksyms
kbuild: Lindent genksyms.c
kbuild: fix genksyms build error
kbuild: in makefile.txt note that Makefile is preferred name for kbuild files
kbuild: replace PHONY with FORCE
kbuild: Fix bug in crc symbol generating of kernel and modules
kbuild: change kbuild to not rely on incorrect GNU make behavior
kbuild: when warning symbols exported twice now tell user this is the problem
kbuild: fix make dir/file.xx when asm symlink is missing
kbuild: in the section mismatch check try harder to find symbols
kbuild: fix section mismatch check for unwind on IA64
kbuild: kill false positives from section mismatch warnings for powerpc
kbuild: kill trailing whitespace in modpost & friends
kbuild: small update of allnoconfig description
kbuild: make namespace.pl CROSS_COMPILE happy
...
Trivial conflict in arch/ppc/boot/Makefile manually fixed up
* git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial: (21 commits)
BUG_ON() Conversion in drivers/video/
BUG_ON() Conversion in drivers/parisc/
BUG_ON() Conversion in drivers/block/
BUG_ON() Conversion in sound/sparc/cs4231.c
BUG_ON() Conversion in drivers/s390/block/dasd.c
BUG_ON() Conversion in lib/swiotlb.c
BUG_ON() Conversion in kernel/cpu.c
BUG_ON() Conversion in ipc/msg.c
BUG_ON() Conversion in block/elevator.c
BUG_ON() Conversion in fs/coda/
BUG_ON() Conversion in fs/binfmt_elf_fdpic.c
BUG_ON() Conversion in input/serio/hil_mlc.c
BUG_ON() Conversion in md/dm-hw-handler.c
BUG_ON() Conversion in md/bitmap.c
The comment describing how MS_ASYNC works in msync.c is confusing
rcu: undeclared variable used in documentation
fix typos "wich" -> "which"
typo patch for fs/ufs/super.c
Fix simple typos
tabify drivers/char/Makefile
...
In frontlight support, we should really use values from flash-ROM instead
of hardcoding our own. Cleanup includes.
Signed-off-by: Pavel Machek <pavel@suse.cz>
Acked-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove the assumption that driver_register() returns the number of devices
bound to the driver. In fact, it returns zero for success or a negative
error value.
zorro_module_init() used the device count to automatically unregister and
unload drivers that found no devices. That might have worked at one time,
but has been broken for some time because zorro_register_driver() returned
either a negative error or a positive count (never zero). So it could only
unregister on failure, when it's not needed anyway.
This functionality could be resurrected in individual drivers by counting
devices in their .probe() methods.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove the assumption that driver_register() returns the number of devices
bound to the driver. In fact, it returns zero for success or a negative
error value.
dio_module_init() used the device count to automatically unregister and
unload drivers that found no devices. That might have worked at one time,
but has been broken for some time because dio_register_driver() returned
either a negative error or a positive count (never zero). So it could only
unregister on failure, when it's not needed anyway.
This functionality could be resurrected in individual drivers by counting
devices in their .probe() methods.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Philip Blundell <philb@gnu.org>
Cc: Jochen Friedrich <jochen@scram.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
MODULE_PARM was actually breaking: recent gcc version optimize them out as
unused. It's time to replace the last users, which are generally in the
most unloved drivers anyway.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
* master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6:
[SPARC64]: Add a secondary TSB for hugepage mappings.
[SPARC]: Respect vm_page_prot in io_remap_page_range().
set_page_count usage outside mm/ is limited to setting the refcount to 1.
Remove set_page_count from outside mm/, and replace those users with
init_page_count() and set_page_refcounted().
This allows more debug checking, and tighter control on how code is allowed
to play around with page->_count.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The console cursor can be called in atomic context. Change memory
allocation to use the GFP_ATOMIC flag in i810fb_cursor().
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* master.kernel.org:/pub/scm/linux/kernel/git/gregkh/driver-2.6: (23 commits)
[PATCH] sysfs: fix a kobject leak in sysfs_add_link on the error path
[PATCH] sysfs: don't export dir symbols
[PATCH] get_cpu_sysdev() signedness fix
[PATCH] kobject_add_dir
[PATCH] debugfs: Add debugfs_create_blob() helper for exporting binary data
[PATCH] sysfs: fix problem with duplicate sysfs directories and files
[PATCH] Kobject: kobject.h: fix a typo
[PATCH] Kobject: provide better warning messages when people do stupid things
[PATCH] Driver core: add macros notice(), dev_notice()
[PATCH] firmware: fix BUG: in fw_realloc_buffer
[PATCH] sysfs: kzalloc conversion
[PATCH] fix module sysfs files reference counting
[PATCH] add EXPORT_SYMBOL_GPL_FUTURE() to USB subsystem
[PATCH] add EXPORT_SYMBOL_GPL_FUTURE() to RCU subsystem
[PATCH] add EXPORT_SYMBOL_GPL_FUTURE()
[PATCH] Clean up module.c symbol searching logic
[PATCH] kobj_map semaphore to mutex conversion
[PATCH] kref: avoid an atomic operation in kref_put()
[PATCH] handle errors returned by platform_get_irq*()
[PATCH] driver core: platform_get_irq*(): return -ENXIO on error
...
platform_get_irq*() now returns on -ENXIO when the resource cannot be
found. Ensure all users of platform_get_irq*() handle this error
appropriately.
Signed-off-by: David Vrabel <dvrabel@arcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch removes a dead Radeon URL from two Kconfig files.
This isue was noted by Reto Gantenbein <ganto82@gmx.ch> in
Kernel Bugzilla #4446.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
radeonfb_parse_monitor_layout() will produce an array overrun if passed with a
substring of length higher than 4 (ie, "XXXXX,YYYYYY").
Coverity Bug 494
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The pseudo_palette has room only for 16 entries, but tdfxfb_setcolreg may
attempt to write more.
Coverity Bug 557
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The pseudo_palette has room only for 16 entries, but intelfb_setcolreg will
attempt to write more.
Coverity Bug 558
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
par->edid is kfree'd before using in fb_edid_to_monspecs()
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The struct info and device resource may not be released in the driver's error
path. Fix.
Coverity Bug 671
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
struct info may not be released in the driver's error path.
Coverity Bug 672
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
info->par is dereferenced before info is checked for NULL. Fix.
Coverity Bug 833
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
ERR_PTR() is supposed to be passed a negative value.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The setcolreg function will attempt to write 24 color entries to the
pseudo_pallette. However, the pseudo_palette has only space for 16 entries.
Thanks to Atsushi Nemoto for reporting this bug.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Replaced the no longer existing io_remap_page_range() routine with the
io_remap_pfn_range() routine. Did not have a chance yet to test the
functionality of the driver, but at least the kernel compiles cleanly again.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Allocating more than 4 MB memory for the GBE (SGI O2) framebuffer completely
breakfs gbefb support at the moment. According to comments on #mipslinux,
more than 4 MB has never worked correctly in Linux. Therefore, the default
should be 4 MB.
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The gbefb driver does not update the framebuffer layers visual setting when
depth is changed with fbset, resulting in strange colors (very dark blue in
16-bit, almost black in 24-bit).
Signed-off-by: Kaj-Michael Lang <milang@tal.org>
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
EGA boards suck: they mostly have write-only registers. This is
particularly problematic for the overflow register: for being able to write
to it, we would have to handle vertical sync & such too, which (I'd say)
would potentially break a lot of configurations. Instead, just disabling
vertical resize for EGA boards is just nice enough (horizontal resize still
works).
Fixes http://bugzilla.kernel.org/show_bug.cgi?id=6106
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Rafal Olearski <olearski@mail2.kim.net.pl>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make resume from suspend-to-ram possible for Samsung P35 laptops.
The radeon mobility 9700 chip on Samsung P35 laptops locks up everything on
resume from suspend-to-ram if it is not reinitialized.
VGA compatible controller: ATI Technologies Inc RV350 [Mobility Radeon 9600 M10]
Class 0300: 1002:4e50
Subsystem: 144d:c00c
Unfortunately, the DMI strings are mostly identical for all Samsung
laptops. So we match the PCI ID and subsystem ID of the graphics card
which is unique for each Samsung laptop model.
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
checkconfig.pl is no longer needed now that autoconf.h is automatically
included. Remove it and all references to it.
Signed-off-by: Brian Gerst <bgerst@didntduck.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
A sysfs function call uses the wrong parameter, and thus breaks a build on
SGI O2.
CC drivers/video/gbefb.o
drivers/video/gbefb.c: In function ‘gbefb_remove’:
drivers/video/gbefb.c:1246: error: ‘dev’ undeclared (first use in this function)
drivers/video/gbefb.c:1246: error: (Each undeclared identifier is reported only once
drivers/video/gbefb.c:1246: error: for each function it appears in.)
make[2]: *** [drivers/video/gbefb.o] Error 1
Signed-off-by: Joshua Kinard <kumba@gentoo.org>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There were two mistakes in the register-read-on-(un)blank approach.
- First, without proper register (un)locking the value read back will always
be zero, and this is what I missed entirely until just now. Due to this,
the logic could not be verified at all and I tried some bogus checks which
are completely stupid.
- Second, the LCD status bit will always be set to zero when the backlight
has been turned off. Reading the value back during unblank will disable the
LCD unconditionally, regardless of the state it is supposed to be in, since
we set it to zero beforehand.
So this is what we do now:
- create a new variable in struct neofb_par, and use that to determine
whether to read back registers (initialized to true)
- before actually blanking the screen, read back the register to sense any
possible change made through Fn key combo
- use proper neoUnlock() / neoLock() to actually read something
- every call to neofb_blank() determines if we read back next time: blanking
disables readback, unblanking (FB_BLANK_UNBLANK) enables it
This should give us a nice and clean state machine. Has been thoroughly
tested on a Dell Latitude CPiA / NM220 Chip docked to a C/Dock2 with attached
CRT in all possible combinations of LCD/CRT on/off. I changed the config via
Fn key, let the console blank, unblanked by keypress - works flawlessly.
Signed-off-by: Christian Trefzer <ctrefzer@gmx.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix issues with the NeoMagic framebuffer driver.
It nicely complements my previous fix already in linus' tree. The only
thing missing now is that the external CRT will not be activated at neofb
init when external-only is selected, either by register read or
module/kernel parameter.
Testing was done on a Dell Latitude CPi-A/NM2200 chip.
Previous behaviour:
- before booting linux, set the preferred display config X via FN+F8
- boot linux, neofb stores the register values in a private
variable
- change the display config to Y via keystroke
- leave the machine in peace until display is blanked
- touching any key will result in display config X being restored
- booting up, the BIOS will acknowledge config Y, though...
Current behaviour:
At the time of unblanking, config Y is honoured because we now read back
register contents instead of just overwriting them with outdated values.
Signed-off by: Christian Trefzer <ctrefzer@gmx.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
drivers/video/fbmem.c:1567: warning: 'video_setup' defined but not used
Acked-by: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The BUS_I2C option is neither available (since there is no VISWS option in
the kernel) nor does it have any effect - so why not remove it?
Based on a report by Jean-Luc Leger <reiga@dspnet.fr.eu.org>.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A bunch of asm/bug.h includes are both not needed (since it will get
pulled anyway) and bogus (since they are done too early). Removed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Some time before 2.6.15, a third DDC channel was added to i810fb. On
systems where these ddc pins are not connected, the probe takes about 10
seconds.
Add a boot/module option for i810fb to explicitly probe for the 3rd ddc bus
if needed.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This adds support for the hp680 backlight, as found in the hp6xx series of
sh devices.
Signed-off-by: Andriy Skulysh <askulysh@image.kiev.ua>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
