05 Aug, 2011
1 commit
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…l/git/tip/linux-2.6-tip
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
slab, lockdep: Annotate the locks before using them
lockdep: Clear whole lockdep_map on initialization
slab, lockdep: Annotate slab -> rcu -> debug_object -> slab
lockdep: Fix up warning
lockdep: Fix trace_hardirqs_on_caller()
futex: Fix regression with read only mappings
04 Aug, 2011
7 commits
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lockdep_init_map() only initializes parts of lockdep_map and triggers
kmemcheck warning when it is copied as a whole. There isn't anything
to be gained by clearing selectively. memset() the whole structure
and remove loop for ->class_cache[] clearing.Addresses https://bugzilla.kernel.org/show_bug.cgi?id=35532
Signed-off-by: Tejun Heo
Reported-and-tested-by: Christian Casteyde
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=35532
Signed-off-by: Peter Zijlstra
Link: http://lkml.kernel.org/r/20110714131909.GJ3455@htj.dyndns.org
Signed-off-by: Ingo Molnar -
On Sun, 2011-07-24 at 21:06 -0400, Arnaud Lacombe wrote:
> /src/linux/linux/kernel/lockdep.c: In function 'mark_held_locks':
> /src/linux/linux/kernel/lockdep.c:2471:31: warning: comparison of
> distinct pointer types lacks a castThe warning is harmless in this case, but the below makes it go away.
Reported-by: Arnaud Lacombe
Signed-off-by: Peter Zijlstra
Link: http://lkml.kernel.org/r/1311588599.2617.56.camel@laptop
Signed-off-by: Ingo Molnar -
Commit dd4e5d3ac4a ("lockdep: Fix trace_[soft,hard]irqs_[on,off]()
recursion") made a bit of a mess of the various checks and error
conditions.In particular it moved the check for !irqs_disabled() before the
spurious enable test, resulting in some warnings.Reported-by: Arnaud Lacombe
Reported-by: Dave Jones
Reported-and-tested-by: Sergey Senozhatsky
Signed-off-by: Peter Zijlstra
Link: http://lkml.kernel.org/r/1311679697.24752.28.camel@twins
Signed-off-by: Ingo Molnar -
The core device layer sends tons of uevent notifications for each device
it finds, and if the kernel has been built with a non-empty
CONFIG_UEVENT_HELPER_PATH that will make us try to execute the usermode
helper binary for all these events very early in the boot.Not only won't the root filesystem even be mounted at that point, we
literally won't have necessarily even initialized all the process
handling data structures at that point, which causes no end of silly
problems even when the usermode helper doesn't actually succeed in
executing.So just use our existing infrastructure to disable the usermodehelpers
to make the kernel start out with them disabled. We enable them when
we've at least initialized stuff a bit.Problems related to an uninitialized
init_ipc_ns.ids[IPC_SHM_IDS].rw_mutex
reported by various people.
Reported-by: Manuel Lauss
Reported-by: Richard Weinberger
Reported-by: Marc Zyngier
Acked-by: Kay Sievers
Cc: Andrew Morton
Cc: Vasiliy Kulikov
Cc: Greg KH
Signed-off-by: Linus Torvalds -
When send_cpu_listeners() finds the orphaned listener it marks it as
!valid and drops listeners->sem. Before it takes this sem for writing,
s->pid can be reused and add_del_listener() can wrongly try to re-use
this entry.Change add_del_listener() to check ->valid = T.
Signed-off-by: Oleg Nesterov
Reviewed-by: Vasiliy Kulikov
Acked-by: Balbir Singh
Cc: Jerome Marchand
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
1. Commit 26c4caea9d69 "don't allow duplicate entries in listener mode"
changed add_del_listener(REGISTER) so that "next_cpu:" can reuse the
listener allocated for the previous cpu, this doesn't look exactly
right even if minor.Change the code to kfree() in the already-registered case, this case
is unlikely anyway so the extra kmalloc_node() shouldn't hurt but
looke more correct and clean.2. use the plain list_for_each_entry() instead of _safe() to scan
listeners->list.3. Remove the unneeded INIT_LIST_HEAD(&s->list), we are going to
list_add(&s->list).Signed-off-by: Oleg Nesterov
Reviewed-by: Vasiliy Kulikov
Cc: Balbir Singh
Reviewed-by: Jerome Marchand
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
02 Aug, 2011
5 commits
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* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
kdb,kgdb: Allow arbitrary kgdb magic knock sequences
kdb: Remove all references to DOING_KGDB2
kdb,kgdb: Implement switch and pass buffer from kdb -> gdb
kdb: cleanup unused variables missed in the original kdb merge -
The first packet that gdb sends when the kernel is in kdb mode seems
to change with every release of gdb. Instead of continuing to add
many different gdb packets, change kdb to automatically look for any
thing that looks like a gdb packet.Example 1 cold start test:
echo g > /proc/sysrq-trigger
$D#44+Example 2 cold start test:
echo g > /proc/sysrq-trigger
$3#33The second one should re-enter kdb's shell right away and is purely a
test.Signed-off-by: Jason Wessel
-
The DOING_KGDB2 was originally a state variable for one of the two
ways to automatically transition from kdb to kgdb. Purge all these
variables and just use one single state for the transition.Signed-off-by: Jason Wessel
-
When switching from kdb mode to kgdb mode packets were getting lost
depending on the size of the fifo queue of the serial chip. When gdb
initially connects if it is in kdb mode it should entirely send any
character buffer over to the gdbstub when switching connections.Previously kdb was zero'ing out the character buffer and this could
lead to gdb failing to connect at all, or a lengthy pause could occur
on the initial connect.Signed-off-by: Jason Wessel
-
The BTARGS and BTSYMARG variables do not have any function in the
mainline version of kdb.Reported-by: Tim Bird
Signed-off-by: Jason Wessel
01 Aug, 2011
1 commit
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* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
m68k/math-emu: Remove unnecessary code
m68k/math-emu: Remove commented out old code
m68k: Kill warning in setup_arch() when compiling for Sun3
m68k/atari: Prefix GPIO_{IN,OUT} with CODEC_
sparc: iounmap() and *_free_coherent() - Use lookup_resource()
m68k/atari: Reserve some ST-RAM early on for device buffer use
m68k/amiga: Chip RAM - Use lookup_resource()
resources: Add lookup_resource()
sparc: _sparc_find_resource() should check for exact matches
m68k/amiga: Chip RAM - Offset resource end by CHIP_PHYSADDR
m68k/amiga: Chip RAM - Use resource_size() to fix off-by-one error
m68k/amiga: Chip RAM - Change chipavail to an atomic_t
m68k/amiga: Chip RAM - Always allocate from the start of memory
m68k/amiga: Chip RAM - Convert from printk() to pr_*()
m68k/amiga: Chip RAM - Use tabs for indentation
31 Jul, 2011
1 commit
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Add a function to find an existing resource by a resource start address.
This allows to implement simple allocators (with a malloc/free-alike API)
on top of the resource system.Signed-off-by: Geert Uytterhoeven
30 Jul, 2011
2 commits
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* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6: (430 commits)
[media] ir-mce_kbd-decoder: include module.h for its facilities
[media] ov5642: include module.h for its facilities
[media] em28xx: Fix DVB-C maxsize for em2884
[media] tda18271c2dd: Fix saw filter configuration for DVB-C @6MHz
[media] v4l: mt9v032: Fix Bayer pattern
[media] V4L: mt9m111: rewrite set_pixfmt
[media] V4L: mt9m111: fix missing return value check mt9m111_reg_clear
[media] V4L: initial driver for ov5642 CMOS sensor
[media] V4L: sh_mobile_ceu_camera: fix Oops when USERPTR mapping fails
[media] V4L: soc-camera: remove soc-camera bus and devices on it
[media] V4L: soc-camera: un-export the soc-camera bus
[media] V4L: sh_mobile_csi2: switch away from using the soc-camera bus notifier
[media] V4L: add media bus configuration subdev operations
[media] V4L: soc-camera: group struct field initialisations together
[media] V4L: soc-camera: remove now unused soc-camera specific PM hooks
[media] V4L: pxa-camera: switch to using standard PM hooks
[media] NetUP Dual DVB-T/C CI RF: force card hardware revision by module param
[media] Don't OOPS if videobuf_dvb_get_frontend return NULL
[media] NetUP Dual DVB-T/C CI RF: load firmware according card revision
[media] omap3isp: Support configurable HS/VS polarities
...Fix up conflicts:
- arch/arm/mach-omap2/board-rx51-peripherals.c:
cleanup regulator supply definitions in mach-omap2
vs
OMAP3: RX-51: define vdds_csib regulator supply
- drivers/staging/tm6000/tm6000-alsa.c (trivial) -
* 'next/dt' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/linux-arm-soc: (21 commits)
arm/dt: tegra devicetree support
arm/versatile: Add device tree support
dt/irq: add irq_domain_generate_simple() helper
irq: add irq_domain translation infrastructure
dmaengine: imx-sdma: add device tree probe support
dmaengine: imx-sdma: sdma_get_firmware does not need to copy fw_name
dmaengine: imx-sdma: use platform_device_id to identify sdma version
mmc: sdhci-esdhc-imx: add device tree probe support
mmc: sdhci-pltfm: dt device does not pass parent to sdhci_alloc_host
mmc: sdhci-esdhc-imx: get rid of the uses of cpu_is_mx()
mmc: sdhci-esdhc-imx: do not reference platform data after probe
mmc: sdhci-esdhc-imx: extend card_detect and write_protect support for mx5
net/fec: add device tree probe support
net: ibm_newemac: convert it to use of_get_phy_mode
dt/net: add helper function of_get_phy_mode
net/fec: gasket needs to be enabled for some i.mx
serial/imx: add device tree probe support
serial/imx: get rid of the uses of cpu_is_mx1()
arm/dt: Add dtb make rule
arm/dt: Add skeleton dtsi file
...
28 Jul, 2011
6 commits
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irq_domain_generate_simple() is an easy way to generate an irq translation
domain for simple irq controllers. It assumes a flat 1:1 mapping from
hardware irq number to an offset of the first linux irq number assigned
to the controllerSigned-off-by: Grant Likely
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This patch adds irq_domain infrastructure for translating from
hardware irq numbers to linux irqs. This is particularly important
for architectures adding device tree support because the current
implementation (excluding PowerPC and SPARC) cannot handle
translation for more than a single interrupt controller. irq_domain
supports device tree translation for any number of interrupt
controllers.This patch converts x86, Microblaze, ARM and MIPS to use irq_domain
for device tree irq translation. x86 is untested beyond compiling it,
irq_domain is enabled for MIPS and Microblaze, but the old behaviour is
preserved until the core code is modified to actually register an
irq_domain yet. On ARM it works and is required for much of the new
ARM device tree board support.PowerPC has /not/ been converted to use this new infrastructure. It
is still missing some features before it can replace the virq
infrastructure already in powerpc (see documentation on
irq_domain_map/unmap for details). Followup patches will add the
missing pieces and migrate PowerPC to use irq_domain.SPARC has its own method of managing interrupts from the device tree
and is unaffected by this change.Acked-by: Ralf Baechle
Signed-off-by: Grant Likely -
…s/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (54 commits)
tpm_nsc: Fix bug when loading multiple TPM drivers
tpm: Move tpm_tis_reenable_interrupts out of CONFIG_PNP block
tpm: Fix compilation warning when CONFIG_PNP is not defined
TOMOYO: Update kernel-doc.
tpm: Fix a typo
tpm_tis: Probing function for Intel iTPM bug
tpm_tis: Fix the probing for interrupts
tpm_tis: Delay ACPI S3 suspend while the TPM is busy
tpm_tis: Re-enable interrupts upon (S3) resume
tpm: Fix display of data in pubek sysfs entry
tpm_tis: Add timeouts sysfs entry
tpm: Adjust interface timeouts if they are too small
tpm: Use interface timeouts returned from the TPM
tpm_tis: Introduce durations sysfs entry
tpm: Adjust the durations if they are too small
tpm: Use durations returned from TPM
TOMOYO: Enable conditional ACL.
TOMOYO: Allow using argv[]/envp[] of execve() as conditions.
TOMOYO: Allow using executable's realpath and symlink's target as conditions.
TOMOYO: Allow using owner/group etc. of file objects as conditions.
...Fix up trivial conflict in security/tomoyo/realpath.c
-
Signed-off-by: Hans Verkuil
Signed-off-by: Mauro Carvalho Chehab -
sys_ssetmask(), sys_rt_sigsuspend() and compat_sys_rt_sigsuspend()
change ->blocked directly. This is not correct, see the changelog in
e6fa16ab "signal: sigprocmask() should do retarget_shared_pending()"Change them to use set_current_blocked().
Another change is that now we are doing ->saved_sigmask = ->blocked
lockless, it doesn't make any sense to do this under ->siglock.Signed-off-by: Oleg Nesterov
Reviewed-by: Matt Fleming
Acked-by: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
27 Jul, 2011
7 commits
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This allows us to move duplicated code in
(atomic_inc_not_zero() for now) toSigned-off-by: Arun Sharma
Reviewed-by: Eric Dumazet
Cc: Ingo Molnar
Cc: David Miller
Cc: Eric Dumazet
Acked-by: Mike Frysinger
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When a kernel BUG or oops occurs, ChromeOS intends to panic and
immediately reboot, with stacktrace and other messages preserved in RAM
across reboot.But the longer we delay, the more likely the user is to poweroff and
lose the info.panic_timeout (seconds before rebooting) is set by panic= boot option or
sysctl or /proc/sys/kernel/panic; but 0 means wait forever, so at
present we have to delay at least 1 second.Let a negative number mean reboot immediately (with the small cosmetic
benefit of suppressing that newline-less "Rebooting in %d seconds.."
message).Signed-off-by: Hugh Dickins
Signed-off-by: Mandeep Singh Baines
Cc: Huang Ying
Cc: Andi Kleen
Cc: Hugh Dickins
Cc: Olaf Hering
Cc: Jesse Barnes
Cc: Dave Airlie
Cc: Greg Kroah-Hartman
Cc: Alan Cox
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Selecting GCOV for UML causing configuration mismatch:
warning: (GCOV_KERNEL) selects CONSTRUCTORS which has unmet direct dependencies (!UML)
Constructors are not needed for UML.
Signed-off-by: Vitaliy Ivanov
Cc: Peter Oberparleiter
Acked-by: Richard Weinberger
Acked-by: WANG Cong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add support for the shm_rmid_forced sysctl. If set to 1, all shared
memory objects in current ipc namespace will be automatically forced to
use IPC_RMID.The POSIX way of handling shmem allows one to create shm objects and
call shmdt(), leaving shm object associated with no process, thus
consuming memory not counted via rlimits.With shm_rmid_forced=1 the shared memory object is counted at least for
one process, so OOM killer may effectively kill the fat process holding
the shared memory.It obviously breaks POSIX - some programs relying on the feature would
stop working. So set shm_rmid_forced=1 only if you're sure nobody uses
"orphaned" memory. Use shm_rmid_forced=0 by default for compatability
reasons.The feature was previously impemented in -ow as a configure option.
[akpm@linux-foundation.org: fix documentation, per Randy]
[akpm@linux-foundation.org: fix warning]
[akpm@linux-foundation.org: readability/conventionality tweaks]
[akpm@linux-foundation.org: fix shm_rmid_forced/shm_forced_rmid confusion, use standard comment layout]
Signed-off-by: Vasiliy Kulikov
Cc: Randy Dunlap
Cc: "Eric W. Biederman"
Cc: "Serge E. Hallyn"
Cc: Daniel Lezcano
Cc: Oleg Nesterov
Cc: Tejun Heo
Cc: Ingo Molnar
Cc: Alan Cox
Cc: Solar Designer
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Signed-off-by: Daniel Rebelo de Oliveira
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
[ This patch has already been accepted as commit 0ac0c0d0f837 but later
reverted (commit 35926ff5fba8) because it itroduced arch specific
__node_random which was defined only for x86 code so it broke other
archs. This is a followup without any arch specific code. Other than
that there are no functional changes.]Some workloads that create a large number of small files tend to assign
too many pages to node 0 (multi-node systems). Part of the reason is
that the rotor (in cpuset_mem_spread_node()) used to assign nodes starts
at node 0 for newly created tasks.This patch changes the rotor to be initialized to a random node number
of the cpuset.[akpm@linux-foundation.org: fix layout]
[Lee.Schermerhorn@hp.com: Define stub numa_random() for !NUMA configuration]
[mhocko@suse.cz: Make it arch independent]
[akpm@linux-foundation.org: fix CONFIG_NUMA=y, MAX_NUMNODES>1 build]
Signed-off-by: Jack Steiner
Signed-off-by: Lee Schermerhorn
Signed-off-by: Michal Hocko
Reviewed-by: KOSAKI Motohiro
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: Paul Menage
Cc: Jack Steiner
Cc: Robin Holt
Cc: David Rientjes
Cc: Christoph Lameter
Cc: David Rientjes
Cc: Jack Steiner
Cc: KOSAKI Motohiro
Cc: Lee Schermerhorn
Cc: Michal Hocko
Cc: Paul Menage
Cc: Pekka Enberg
Cc: Robin Holt
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
commit 7485d0d3758e8e6491a5c9468114e74dc050785d (futexes: Remove rw
parameter from get_futex_key()) in 2.6.33 fixed two problems: First, It
prevented a loop when encountering a ZERO_PAGE. Second, it fixed RW
MAP_PRIVATE futex operations by forcing the COW to occur by
unconditionally performing a write access get_user_pages_fast() to get
the page. The commit also introduced a user-mode regression in that it
broke futex operations on read-only memory maps. For example, this
breaks workloads that have one or more reader processes doing a
FUTEX_WAIT on a futex within a read only shared file mapping, and a
writer processes that has a writable mapping issuing the FUTEX_WAKE.This fixes the regression for valid futex operations on RO mappings by
trying a RO get_user_pages_fast() when the RW get_user_pages_fast()
fails. This change makes it necessary to also check for invalid use
cases, such as anonymous RO mappings (which can never change) and the
ZERO_PAGE which the commit referenced above was written to address.This patch does restore the original behavior with RO MAP_PRIVATE
mappings, which have inherent user-mode usage problems and don't really
make sense. With this patch performing a FUTEX_WAIT within a RO
MAP_PRIVATE mapping will be successfully woken provided another process
updates the region of the underlying mapped file. However, the mmap()
man page states that for a MAP_PRIVATE mapping:It is unspecified whether changes made to the file after
the mmap() call are visible in the mapped region.So user-mode users attempting to use futex operations on RO MAP_PRIVATE
mappings are depending on unspecified behavior. Additionally a
RO MAP_PRIVATE mapping could fail to wake up in the following case.Thread-A: call futex(FUTEX_WAIT, memory-region-A).
get_futex_key() return inode based key.
sleep on the key
Thread-B: call mprotect(PROT_READ|PROT_WRITE, memory-region-A)
Thread-B: write memory-region-A.
COW happen. This process's memory-region-A become related
to new COWed private (ie PageAnon=1) page.
Thread-B: call futex(FUETX_WAKE, memory-region-A).
get_futex_key() return mm based key.
IOW, we fail to wake up Thread-A.Once again doing something like this is just silly and users who do
something like this get what they deserve.While RO MAP_PRIVATE mappings are nonsensical, checking for a private
mapping requires walking the vmas and was deemed too costly to avoid a
userspace hang.This Patch is based on Peter Zijlstra's initial patch with modifications to
only allow RO mappings for futex operations that need VERIFY_READ access.Reported-by: David Oliver
Signed-off-by: Shawn Bohrer
Acked-by: Peter Zijlstra
Signed-off-by: Darren Hart
Cc: KOSAKI Motohiro
Cc: peterz@infradead.org
Cc: eric.dumazet@gmail.com
Cc: zvonler@rgmadvisors.com
Cc: hughd@google.com
Link: http://lkml.kernel.org/r/1309450892-30676-1-git-send-email-sbohrer@rgmadvisors.com
Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner
26 Jul, 2011
8 commits
-
* Merge akpm patch series: (122 commits)
drivers/connector/cn_proc.c: remove unused local
Documentation/SubmitChecklist: add RCU debug config options
reiserfs: use hweight_long()
reiserfs: use proper little-endian bitops
pnpacpi: register disabled resources
drivers/rtc/rtc-tegra.c: properly initialize spinlock
drivers/rtc/rtc-twl.c: check return value of twl_rtc_write_u8() in twl_rtc_set_time()
drivers/rtc: add support for Qualcomm PMIC8xxx RTC
drivers/rtc/rtc-s3c.c: support clock gating
drivers/rtc/rtc-mpc5121.c: add support for RTC on MPC5200
init: skip calibration delay if previously done
misc/eeprom: add eeprom access driver for digsy_mtc board
misc/eeprom: add driver for microwire 93xx46 EEPROMs
checkpatch.pl: update $logFunctions
checkpatch: make utf-8 test --strict
checkpatch.pl: add ability to ignore various messages
checkpatch: add a "prefer __aligned" check
checkpatch: validate signature styles and To: and Cc: lines
checkpatch: add __rcu as a sparse modifier
checkpatch: suggest using min_t or max_t
...Did this as a merge because of (trivial) conflicts in
- Documentation/feature-removal-schedule.txt
- arch/xtensa/include/asm/uaccess.h
that were just easier to fix up in the merge than in the patch series. -
If CONFIG_IKCONFIG=m but CONFIG_IKCONFIG_PROC=n we get a module that has
no MODULE_LICENSE definition. Move the MODULE_*() definitions outside the
CONFIG_IKCONFIG_PROC #ifdef to prevent this configuration from tainting
the kernel.Signed-off-by: Stephen Boyd
Acked-by: Randy Dunlap
Acked-by: WANG Cong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
It is not necessary to share the same notifier.h.
This patch already moves register_reboot_notifier() and
unregister_reboot_notifier() from kernel/notifier.c to kernel/sys.c.[amwang@redhat.com: make allyesconfig succeed on ppc64]
Signed-off-by: WANG Cong
Cc: David Miller
Cc: "Rafael J. Wysocki"
Cc: Greg KH
Signed-off-by: WANG Cong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
devres uses the pointer value as key after it's freed, which is safe but
triggers spurious use-after-free warnings on some static analysis tools.
Rearrange code to avoid such warnings.Signed-off-by: Maxin B. John
Reviewed-by: Rolf Eike Beer
Acked-by: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
I haven't reproduced it myself but the fail scenario is that on such
machines (notably ARM and some embedded powerpc), if you manage to hit
that futex path on a writable page whose dirty bit has gone from the PTE,
you'll livelock inside the kernel from what I can tell.It will go in a loop of trying the atomic access, failing, trying gup to
"fix it up", getting succcess from gup, go back to the atomic access,
failing again because dirty wasn't fixed etc...So I think you essentially hang in the kernel.
The scenario is probably rare'ish because affected architecture are
embedded and tend to not swap much (if at all) so we probably rarely hit
the case where dirty is missing or young is missing, but I think Shan has
a piece of SW that can reliably reproduce it using a shared writable
mapping & fork or something like that.On archs who use SW tracking of dirty & young, a page without dirty is
effectively mapped read-only and a page without young unaccessible in the
PTE.Additionally, some architectures might lazily flush the TLB when relaxing
write protection (by doing only a local flush), and expect a fault to
invalidate the stale entry if it's still present on another processor.The futex code assumes that if the "in_atomic()" access -EFAULT's, it can
"fix it up" by causing get_user_pages() which would then be equivalent to
taking the fault.However that isn't the case. get_user_pages() will not call
handle_mm_fault() in the case where the PTE seems to have the right
permissions, regardless of the dirty and young state. It will eventually
update those bits ... in the struct page, but not in the PTE.Additionally, it will not handle the lazy TLB flushing that can be
required by some architectures in the fault case.Basically, gup is the wrong interface for the job. The patch provides a
more appropriate one which boils down to just calling handle_mm_fault()
since what we are trying to do is simulate a real page fault.The futex code currently attempts to write to user memory within a
pagefault disabled section, and if that fails, tries to fix it up using
get_user_pages().This doesn't work on archs where the dirty and young bits are maintained
by software, since they will gate access permission in the TLB, and will
not be updated by gup().In addition, there's an expectation on some archs that a spurious write
fault triggers a local TLB flush, and that is missing from the picture as
well.I decided that adding those "features" to gup() would be too much for this
already too complex function, and instead added a new simpler
fixup_user_fault() which is essentially a wrapper around handle_mm_fault()
which the futex code can call.[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix some nits Darren saw, fiddle comment layout]
Signed-off-by: Benjamin Herrenschmidt
Reported-by: Shan Hai
Tested-by: Shan Hai
Cc: David Laight
Acked-by: Peter Zijlstra
Cc: Darren Hart
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
…linux/kernel/git/mmarek/kbuild-2.6
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
genksyms: Use same type in loop comparison
kbuild: silence generated makefile message
kernel: prevent unnecessary rebuilding due to config_data.gz
headers_install: fix __packed in exported kernel headers
dtc: regen parser
dtc: migrate parser to implicit rules
kconfig: regen parser
kconfig: migrate parser to implicit rules
kconfig/zconf.l: do not ask to generate backup
kconfig: kill no longer needed reference to YYDEBUG
kconfig: constify `kconf_id_lookup'
genksym: regen parser
genksyms: migrate parser to implicit rules
genksyms: drop -Wno-uninitialized from HOSTCFLAGS_parse.tab.o
genksyms: pass hash and lookup functions name and target language though the input file
kbuild: simplify the %_shipped rule
kbuild: add implicit rules for parser generation
kbuild: add `baseprereq'
kbuild: Fix reference to vermagic.h* 'packaging' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
package: Makefile: fix perf target bug* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
gitignore: ignore debian build directory -
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits)
fs: Merge split strings
treewide: fix potentially dangerous trailing ';' in #defined values/expressions
uwb: Fix misspelling of neighbourhood in comment
net, netfilter: Remove redundant goto in ebt_ulog_packet
trivial: don't touch files that are removed in the staging tree
lib/vsprintf: replace link to Draft by final RFC number
doc: Kconfig: `to be' -> `be'
doc: Kconfig: Typo: square -> squared
doc: Konfig: Documentation/power/{pm => apm-acpi}.txt
drivers/net: static should be at beginning of declaration
drivers/media: static should be at beginning of declaration
drivers/i2c: static should be at beginning of declaration
XTENSA: static should be at beginning of declaration
SH: static should be at beginning of declaration
MIPS: static should be at beginning of declaration
ARM: static should be at beginning of declaration
rcu: treewide: Do not use rcu_read_lock_held when calling rcu_dereference_check
Update my e-mail address
PCIe ASPM: forcedly -> forcibly
gma500: push through device driver tree
...Fix up trivial conflicts:
- arch/arm/mach-ep93xx/dma-m2p.c (deleted)
- drivers/gpio/gpio-ep93xx.c (renamed and context nearby)
- drivers/net/r8169.c (just context changes) -
* 'for-3.1/core' of git://git.kernel.dk/linux-block: (24 commits)
block: strict rq_affinity
backing-dev: use synchronize_rcu_expedited instead of synchronize_rcu
block: fix patch import error in max_discard_sectors check
block: reorder request_queue to remove 64 bit alignment padding
CFQ: add think time check for group
CFQ: add think time check for service tree
CFQ: move think time check variables to a separate struct
fixlet: Remove fs_excl from struct task.
cfq: Remove special treatment for metadata rqs.
block: document blk_plug list access
block: avoid building too big plug list
compat_ioctl: fix make headers_check regression
block: eliminate potential for infinite loop in blkdev_issue_discard
compat_ioctl: fix warning caused by qemu
block: flush MEDIA_CHANGE from drivers on close(2)
blk-throttle: Make total_nr_queued unsigned
block: Add __attribute__((format(printf...) and fix fallout
fs/partitions/check.c: make local symbols static
block:remove some spare spaces in genhd.c
block:fix the comment error in blkdev.h
...
25 Jul, 2011
2 commits
-
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
modpost: Fix modpost's license checking V3
module: add /sys/module//uevent files
module: change attr callbacks to take struct module_kobject
modules: make arch's use default loader hooks
modules: add default loader hook implementations
param: fix return value handling in param_set_* -
* 'kvm-updates/3.1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (143 commits)
KVM: IOMMU: Disable device assignment without interrupt remapping
KVM: MMU: trace mmio page fault
KVM: MMU: mmio page fault support
KVM: MMU: reorganize struct kvm_shadow_walk_iterator
KVM: MMU: lockless walking shadow page table
KVM: MMU: do not need atomicly to set/clear spte
KVM: MMU: introduce the rules to modify shadow page table
KVM: MMU: abstract some functions to handle fault pfn
KVM: MMU: filter out the mmio pfn from the fault pfn
KVM: MMU: remove bypass_guest_pf
KVM: MMU: split kvm_mmu_free_page
KVM: MMU: count used shadow pages on prepareing path
KVM: MMU: rename 'pt_write' to 'emulate'
KVM: MMU: cleanup for FNAME(fetch)
KVM: MMU: optimize to handle dirty bit
KVM: MMU: cache mmio info on page fault path
KVM: x86: introduce vcpu_mmio_gva_to_gpa to cleanup the code
KVM: MMU: do not update slot bitmap if spte is nonpresent
KVM: MMU: fix walking shadow page table
KVM guest: KVM Steal time registration
...