The BIOS pin configs are in fact correct and shall not be overwritten.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
HP Compaq 6530s and 6531s internal speaker is silence or becomes silence
within 1 minute after fresh boot. It is found that pin 0x1c must be set to
PIN_OUT mode to make the speaker work. This is weird - line-in pin 0x1c and
speaker pin 0x16 seem to be unrelated.
The codec differences before/after patch are:
@@ Node 0x17 [Pin Complex] wcaps 0x40020b:
Pin Default 0x41a6e130: [N/A] Mic at Ext Rear
Conn = Digital, Color = White
DefAssociation = 0x3, Sequence = 0x0
Misc = NO_PRESENCE
- Pin-ctls: 0x24: IN
+ Pin-ctls: 0x40: OUT
@@ Node 0x1c [Pin Complex] wcaps 0x40018d:
Pin Default 0x41813021: [N/A] Line In at Ext Rear
Conn = 1/8, Color = Blue
DefAssociation = 0x2, Sequence = 0x1
- Pin-ctls: 0x24: IN VREF_80
+ Pin-ctls: 0x40: OUT VREF_HIZ
Unsolicited: tag=00, enabled=0
Connection: 1
0x24
Tests show that it won't impact (external) Mic recording.
Reported-by: "Lin, Ming M" <ming.m.lin@intel.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
If userspace destroys a framebuffer that is in use on a crtc,
don't just null it out, tear down the crtc properly so the
hw gets turned off.
Signed-off-by: Dave Airlie <airlied@redhat.com>
The fallback case wasn't getting executed properly if there
was no TV table, which my T42 M7 hasn't got.
Signed-off-by: Dave Airlie <airlied@redhat.com>
LVDS always requests RMX_FULL, we need to fix it so that doesn't happen
before we can enable LVDS on crtc 1.
Signed-off-by: Dave Airlie <airlied@redhat.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
security: Fix prompt for LSM_MMAP_MIN_ADDR
security: Make LSM_MMAP_MIN_ADDR default match its help text.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu: use the right flag for get_vm_area()
percpu, sparc64: fix sparse possible cpu map handling
init: set nr_cpu_ids before setup_per_cpu_areas()
If node_load[] is cleared everytime build_zonelists() is
called,node_load[] will have no help to find the next node that should
appear in the given node's fallback list.
Because of the bug, zonelist's node_order is not calculated as expected.
This bug affects on big machine, which has asynmetric node distance.
[synmetric NUMA's node distance]
0 1 2
0 10 12 12
1 12 10 12
2 12 12 10
[asynmetric NUMA's node distance]
0 1 2
0 10 12 20
1 12 10 14
2 20 14 10
This (my bug) is very old but no one has reported this for a long time.
Maybe because the number of asynmetric NUMA is very small and they use
cpuset for customizing node memory allocation fallback.
[akpm@linux-foundation.org: fix CONFIG_NUMA=n build]
Signed-off-by: Bo Liu <bo-liu@hotmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
According to the POSIX (1003.1-2008), the file descriptor shall have been
opened with read permission, regardless of the protection options specified to
mmap(). The ltp test cases mmap06/07 need this.
Signed-off-by: Graff Yang <graff.yang@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since the changes to the bitbang driver, there is the possibility we will
be called with either the speed_hz or bpw values zero. We take these to
mean that the default values (8 bits per word, or maximum bus speed).
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the clock rate calculation may round as pleased, which means
that it is possible that we will round down and end up with a faster clock
rate than intended.
Change the calculation to use DIV_ROUND_UP() to ensure that we end up with
a clock rate either the same as or lower than the user requested one.
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are a number of individual MMC drivers listed in MAINTAINERS. I
didn't modify those records. Perhaps I should have.
Cc: <linux-mmc@vger.kernel.org>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Nicolas Pitre <nico@cam.org>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Cc: Pavel Pisa <ppisa@pikron.com>
Cc: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Sascha Sommer <saschasommer@freenet.de>
Cc: Ian Molton <ian@mnementh.co.uk>
Cc: Joseph Chan <JosephChan@via.com.tw>
Cc: Harald Welte <HaraldWelte@viatech.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The commit 2ff05b2b (oom: move oom_adj value) moveed the oom_adj value to
the mm_struct. It was a very good first step for sanitize OOM.
However Paul Menage reported the commit makes regression to his job
scheduler. Current OOM logic can kill OOM_DISABLED process.
Why? His program has the code of similar to the following.
...
set_oom_adj(OOM_DISABLE); /* The job scheduler never killed by oom */
...
if (vfork() == 0) {
set_oom_adj(0); /* Invoked child can be killed */
execve("foo-bar-cmd");
}
....
vfork() parent and child are shared the same mm_struct. then above
set_oom_adj(0) doesn't only change oom_adj for vfork() child, it's also
change oom_adj for vfork() parent. Then, vfork() parent (job scheduler)
lost OOM immune and it was killed.
Actually, fork-setting-exec idiom is very frequently used in userland program.
We must not break this assumption.
Then, this patch revert commit 2ff05b2b and related commit.
Reverted commit list
---------------------
- commit 2ff05b2b4e (oom: move oom_adj value from task_struct to mm_struct)
- commit 4d8b9135c3 (oom: avoid unnecessary mm locking and scanning for OOM_DISABLE)
- commit 8123681022 (oom: only oom kill exiting tasks with attached memory)
- commit 933b787b57 (mm: copy over oom_adj value at fork time)
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
get_sb_pseudo sets s_maxbytes to ~0ULL which becomes negative when cast
to a signed value. Fix it to use MAX_LFS_FILESIZE which casts properly
to a positive signed value.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Steve French <smfrench@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Robert Love <rlove@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix prompt for LSM_MMAP_MIN_ADDR.
(Verbs are cool!)
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Commit 788084aba2 added the LSM_MMAP_MIN_ADDR
option, whose help text states "For most ia64, ppc64 and x86 users with lots
of address space a value of 65536 is reasonable and should cause no problems."
Which implies that it's default setting was typoed.
Signed-off-by: Dave Jones <davej@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (60 commits)
net: restore gnet_stats_basic to previous definition
NETROM: Fix use of static buffer
e1000e: fix use of pci_enable_pcie_error_reporting
e1000e: WoL does not work on 82577/82578 with manageability enabled
cnic: Fix locking in init/exit calls.
cnic: Fix locking in start/stop calls.
bnx2: Use mutex on slow path cnic calls.
cnic: Refine registration with bnx2.
cnic: Fix symbol_put_addr() panic on ia64.
gre: Fix MTU calculation for bound GRE tunnels
pegasus: Add new device ID.
drivers/net: fixed drivers that support netpoll use ndo_start_xmit()
via-velocity: Fix test of mii_status bit VELOCITY_DUPLEX_FULL
rt2x00: fix memory corruption in rf cache, add a sanity check
ixgbe: Fix receive on real device when VLANs are configured
ixgbe: Do not return 0 in ixgbe_fcoe_ddp() upon FCP_RSP in DDP completion
netxen: free napi resources during detach
netxen: remove netxen workqueue
ixgbe: fix issues setting rx-usecs with legacy interrupts
can: fix oops caused by wrong rtnl newlink usage
...
will fix kernel oopses like the following:
# mount -t nilfs2 -r -o cp=20 /dev/sdb1 /test1
# mount -t nilfs2 -r -o cp=20 /dev/sdb1 /test2
# umount /test1
# umount /test2
BUG: sleeping function called from invalid context at arch/x86/mm/fault.c:1069
in_atomic(): 0, irqs_disabled(): 1, pid: 3886, name: umount.nilfs2
1 lock held by umount.nilfs2/3886:
#0: (&type->s_umount_key#31){+.+...}, at: [<c10b398a>] deactivate_super+0x52/0x6c
irq event stamp: 1219
hardirqs last enabled at (1219): [<c135c774>] __mutex_unlock_slowpath+0xf8/0x119
hardirqs last disabled at (1218): [<c135c6d5>] __mutex_unlock_slowpath+0x59/0x119
softirqs last enabled at (1214): [<c1033316>] __do_softirq+0x1a5/0x1ad
softirqs last disabled at (1205): [<c1033354>] do_softirq+0x36/0x5a
Pid: 3886, comm: umount.nilfs2 Not tainted 2.6.31-rc6 #55
Call Trace:
[<c1023549>] __might_sleep+0x107/0x10e
[<c13603c0>] do_page_fault+0x246/0x397
[<c136017a>] ? do_page_fault+0x0/0x397
[<c135e753>] error_code+0x6b/0x70
[<c136017a>] ? do_page_fault+0x0/0x397
[<c104f805>] ? __lock_acquire+0x91/0x12fd
[<c1050a62>] ? __lock_acquire+0x12ee/0x12fd
[<c1050a62>] ? __lock_acquire+0x12ee/0x12fd
[<c1050b2b>] lock_acquire+0xba/0xdd
[<d0d17d3f>] ? nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
[<c135d4fe>] down_write+0x2a/0x46
[<d0d17d3f>] ? nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
[<d0d17d3f>] nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
[<c104ea2c>] ? mark_held_locks+0x43/0x5b
[<c104ecb1>] ? trace_hardirqs_on_caller+0x10b/0x133
[<c104ece4>] ? trace_hardirqs_on+0xb/0xd
[<d0d09ac1>] nilfs_put_super+0x2f/0xca [nilfs2]
[<c10b3352>] generic_shutdown_super+0x49/0xb8
[<c10b33de>] kill_block_super+0x1d/0x31
[<c10e6599>] ? vfs_quota_off+0x0/0x12
[<c10b398f>] deactivate_super+0x57/0x6c
[<c10c4bc3>] mntput_no_expire+0x8c/0xb4
[<c10c5094>] sys_umount+0x27f/0x2a4
[<c10c50c6>] sys_oldumount+0xd/0xf
[<c10031a4>] sysenter_do_call+0x12/0x38
...
This turns out to be a bug brought by an -rc1 patch ("nilfs2: simplify
remaining sget() use").
In the patch, a new "put resource" function, nilfs_put_sbinfo()
was introduced to delay freeing nilfs_sb_info struct.
But the nilfs_put_sbinfo() mistakenly used atomic_dec_and_test()
function to check the reference count, and it caused the nilfs_sb_info
was freed when user mounted a snapshot twice.
This bug also suggests there was unseen memory leak in usual mount
/umount operations for nilfs.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
pushd tools/perf/Documentation
make html
popd
is failing for me...
ASCIIDOC perf-annotate.html
ERROR: unsafe: include file: /etc/asciidoc/./stylesheets/xhtml11.css
ERROR: unsafe: include file:
/etc/asciidoc/./stylesheets/xhtml11-manpage.css
ERROR: unsafe: include file:
/etc/asciidoc/./stylesheets/xhtml11-quirks.css
make: *** [perf-annotate.html] Error 1
Apparently asciidoc "unsafe" is the default mode of operation
in practice.
https://bugzilla.redhat.com/show_bug.cgi?id=506953
Works tidily now.
Signed-off-by: Kyle McMartin <kyle@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090818164125.GM25206@bombadil.infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The wake_up_process() of the new irq thread in __setup_irq() is too
early as the irqaction is not yet fully initialized especially
action->irq is not yet set. The interrupt thread might dereference the
wrong irq descriptor.
Move the wakeup after the action is installed and action->irq has been
set.
Reported-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Buesch <mb@bu3sch.de>
Linus reported this perf annotate segfault:
[torvalds@nehalem git]$ perf annotate unmap_vmas
Segmentation fault
#0 map__clone (self=<value optimized out>) at builtin-annotate.c:236
#1 thread__fork (self=<value optimized out>) at builtin-annotate.c:372
The bug here was that builtin-annotate.c was a copy of
builtin-report.c and a threading related fix to builtin-report.c
didnt get propagated to builtin-annotate.c ...
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
PARISC does not build:
/home/mingo/tip/kernel/perf_counter.c: In function 'perf_counter_index':
/home/mingo/tip/kernel/perf_counter.c:2016: error: 'PERF_COUNTER_INDEX_OFFSET' undeclared (first use in this function)
/home/mingo/tip/kernel/perf_counter.c:2016: error: (Each undeclared identifier is reported only once
/home/mingo/tip/kernel/perf_counter.c:2016: error: for each function it appears in.)
As PERF_COUNTER_INDEX_OFFSET is not defined.
Now, we could define it in the architecture - but lets also provide
a core default of 0 (which happens to be what all but one
architecture uses at the moment).
Architectures that need a different index offset should set this
value in their asm/perf_counter.h files.
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
For noMMU system when you use larger rootfs image
there is problem with using _end label because
we increase klimit but in memory initialization
we use still _end which is wrong. Larger mtd rootfs
was rewritten by init_bootmem_node.
MMU kernel use static initialization where klimit
is setup to _end. There is no any other hanling
with klimit.
Signed-off-by: Michal Simek <monstr@monstr.eu>
This code path doesn't test any returned pointers for NULL, leading to a bad
kernel page fault if there's no timer/intc found.
Slightly better is to BUG(), but even better still would be a printk beforehand.
Signed-off-by: John Williams <john.williams@petalogix.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>
'ns_cno' of structure 'the_nilfs' must be protected from segment
writer, in other words, the caller of nilfs_get_checkpoint should hold
read lock for nilfs->ns_segctor_sem. This patch adds the lock/unlock
operations in nilfs_attach_checkpoint() when calling
nilfs_cpfile_get_checkpoint().
Signed-off-by: Zhang Qiang <zhangqiang.buaa@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
In 5e140dfc1f "net: reorder struct Qdisc
for better SMP performance" the definition of struct gnet_stats_basic
changed incompatibly, as copies of this struct are shipped to
userland via netlink.
Restoring old behavior is not welcome, for performance reason.
Fix is to use a private structure for kernel, and
teach gnet_stats_copy_basic() to convert from kernel to user land,
using legacy structure (struct gnet_stats_basic)
Based on a report and initial patch from Michael Spang.
Reported-by: Michael Spang <mspang@csclub.uwaterloo.ca>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The static variable used by nr_call_to_digi might result in corruption if
multiple threads are trying to usee a node or neighbour via ioctl. Fixed
by having the caller pass a structure in. This is safe because nr_add_node
rsp. nr_add_neigh will allocate a permanent structure, if needed.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Recent commit c8c00a6915
changed the exit paths in do_md_stop and was not quite
careful enough. There is one path were 'err' now needs
to be cleared but it isn't.
So setting an array to readonly (with mdadm --readonly) will
work, but will incorrectly report and error: ENXIO.
Signed-off-by: NeilBrown <neilb@suse.de>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
security: define round_hint_to_min in !CONFIG_SECURITY
Security/SELinux: seperate lsm specific mmap_min_addr
SELinux: call cap_file_mmap in selinux_file_mmap
Capabilities: move cap_file_mmap to commoncap.c
The inotify_add_watch man page specifies that inotify_add_watch() will
return a non-negative integer. However, historically the inotify
watches started at 1, not at 0.
Turns out that the inotifywait program provided by the inotify-tools
package doesn't properly handle a 0 watch descriptor. In 7e790dd5 we
changed from starting at 1 to starting at 0. This patch starts at 1,
just like in previous kernels, but also just like in previous kernels
it's possible for it to wrap back to 0. This preserves the kernel
functionality exactly like it was before the patch (neither method broke
the spec)
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In f44aebcc the tail drop logic of events with no file backing
(q_overflow and in_ignored) was reversed so IN_IGNORED events would
never be tail dropped. This now means that Q_OVERFLOW events are NOT
tail dropped. The fix is to not tail drop IN_IGNORED, but to tail drop
Q_OVERFLOW.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
inotify decides if private data it passed to get added to an event was
used by checking list_empty(). But it's possible that the event may
have been dequeued and the private event removed so it would look empty.
The fix is to use the return code from fsnotify_add_notify_event rather
than looking at the list.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch fixes warnings like this:
CC fs/proc/meminfo.o
In file included from /work/linux/include/linux/mmzone.h:20,
from /work/linux/include/linux/gfp.h:4,
from /work/linux/include/linux/mm.h:8,
from /work/linux/fs/proc/meminfo.c:5:
/work/linux/arch/mips/include/asm/page.h:36:1: warning: "HPAGE_SIZE" redefined
In file included from /work/linux/fs/proc/meminfo.c:2:
/work/linux/include/linux/hugetlb.h:107:1: warning: this is the location of the previous definition
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
An older test-box started hanging at the following point during
bootup:
[ 0.022996] Mount-cache hash table entries: 512
[ 0.024996] Initializing cgroup subsys debug
[ 0.025996] Initializing cgroup subsys cpuacct
[ 0.026995] Initializing cgroup subsys devices
[ 0.027995] Initializing cgroup subsys freezer
[ 0.028995] mce: CPU supports 5 MCE banks
I've bisected it down to commit 4efc0670 ("x86, mce: use 64bit
machine check code on 32bit"), which utilizes the MCE code on
32-bit systems too.
The problem is caused by this detail in my config:
# CONFIG_CPU_SUP_INTEL is not set
This disables the quirks in mce_cpu_quirks() but still enables
MCE support - which then hangs due to the missing quirk
workaround needed on this CPU:
if (c->x86 == 6 && c->x86_model < 0x1A && banks > 0)
mce_banks[0].init = 0;
The safe solution is to not initialize MCEs if we dont know on
what CPU we are running (or if that CPU's support code got
disabled in the config).
Also be a bit more defensive on 32-bit systems: dont do a
boot-time dump of pending MCEs not just on the specific system
that we found a problem with (Pentium-M), but earlier ones as
well.
Now this problem is probably not common and disabling CPU
support is rare - but still being more defensive in something
we turned on for a wide range of CPUs is prudent.
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
LKML-Reference: Message-ID: <4A88E3E4.40506@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In general, code in perf_counter.c that is called through an
IPI checks, for per-task counters, that the counter's task is
still the current task. This is to handle the race condition
where the cpu switches from the task we want to another task in
the interval between sending the IPI and the IPI arriving and
being handled on the target CPU.
For some reason, __perf_counter_read is missing this check, yet
there is no reason why the race condition can't occur. This
adds a check that the current task is the one we want. If it
isn't, we just return. In that case the counter->count value
should be up to date, since it will have been updated when the
counter was scheduled out, which must have happened since the
IPI was sent.
I don't have an example of an actual failure due to this race,
but it seems obvious that it could occur and we need to guard
against it.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <19076.63614.277861.368125@drongo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Rename it to examples.txt to avoid the perf-*.txt pattern in
the Makefile, otherwise 'make doc' fails because
perf-examples.txt is not formatted to be a man page:
ERROR: perf-examples.txt: line 1: manpage document title is mandatory
Signed-off-by: Carlos R. Mafra <crmafra@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
