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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: create rcu_my_thread_group_empty() wrapper
memcg: css_id() must be called under rcu_read_lock()
cgroup: Check task_lock in task_subsys_state()
sched: Fix an RCU warning in print_task()
cgroup: Fix an RCU warning in alloc_css_id()
cgroup: Fix an RCU warning in cgroup_path()
KEYS: Fix an RCU warning in the reading of user keys
KEYS: Fix an RCU warning
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Some RCU-lockdep splat repairs need to know whether they are running
in a single-threaded process. Unfortunately, the thread_group_empty()
primitive is defined in sched.h, and can induce #include hell. This
commit therefore introduces a rcu_my_thread_group_empty() wrapper that
is defined in rcupdate.c, thus avoiding the need to include sched.h
everywhere.
Signed-off-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
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* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: flush_delayed_work: keep the original workqueue for re-queueing
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf: Fix resource leak in failure path of perf_event_open()
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: Fix RCU lockdep splat on freezer_fork path
rcu: Fix RCU lockdep splat in set_task_cpu on fork path
mutex: Don't spin when the owner CPU is offline or other weird cases
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With CONFIG_PROVE_RCU=y, a warning can be triggered:
$ cat /proc/sched_debug
...
kernel/cgroup.c:1649 invoked rcu_dereference_check() without protection!
...
Both cgroup_path() and task_group() should be called with either
rcu_read_lock or cgroup_mutex held.
The rcu_dereference_check() does include cgroup_lock_is_held(), so we
know that this lock is not held. Therefore, in a CONFIG_PREEMPT kernel,
to say nothing of a CONFIG_PREEMPT_RT kernel, the original code could
have ended up copying a string out of the freelist.
This patch inserts RCU read-side primitives needed to prevent this
scenario.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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With CONFIG_PROVE_RCU=y, a warning can be triggered:
# mount -t cgroup -o memory xxx /mnt
# mkdir /mnt/0
...
kernel/cgroup.c:4442 invoked rcu_dereference_check() without protection!
...
This is a false-positive. It's safe to directly access parent_css->id.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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with CONFIG_PROVE_RCU=y, a warning can be triggered:
# mount -t cgroup -o debug xxx /mnt
# cat /proc/$$/cgroup
...
kernel/cgroup.c:1649 invoked rcu_dereference_check() without protection!
...
This is a false-positive, because cgroup_path() can be called
with either rcu_read_lock() held or cgroup_mutex held.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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perf_event_open() kfrees event after init failure which doesn't
release all resources allocated by perf_event_alloc(). Use
free_event() instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@au1.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: <stable@kernel.org>
LKML-Reference: <4BDBE237.1040809@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Add an RCU read-side critical section to suppress this false
positive.
Located-by: Eric Paris <eparis@parisplace.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: eric.dumazet@gmail.com
LKML-Reference: <1271880131-3951-2-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Add an RCU read-side critical section to suppress this false
positive.
Located-by: Eric Paris <eparis@parisplace.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: eric.dumazet@gmail.com
LKML-Reference: <1271880131-3951-1-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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flush_delayed_work() always uses keventd_wq for re-queueing,
but it should use the workqueue this dwork was queued on.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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On ppc64 you get this error:
$ setarch ppc -R true
setarch: ppc: Unrecognized architecture
because uname still reports ppc64 as the machine.
So mask off the personality flags when checking for PER_LINUX32.
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Due to recent load-balancer changes that delay the task migration to
the next wakeup, the adaptive mutex spinning ends up in a live lock
when the owner's CPU gets offlined because the cpu_online() check
lives before the owner running check.
This patch changes mutex_spin_on_owner() to return 0 (don't spin) in
any case where we aren't sure about the owner struct validity or CPU
number, and if the said CPU is offline. There is no point going back &
re-evaluate spinning in corner cases like that, let's just go to
sleep.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1271212509.13059.135.camel@pasglop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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creds_are_invalid() reads both cred->usage and cred->subscribers and then
compares them to make sure the number of processes subscribed to a cred struct
never exceeds the refcount of that cred struct.
The problem is that this can cause a race with both copy_creds() and
exit_creds() as the two counters, whilst they are of atomic_t type, are only
atomic with respect to themselves, and not atomic with respect to each other.
This means that if creds_are_invalid() can read the values on one CPU whilst
they're being modified on another CPU, and so can observe an evolving state in
which the subscribers count now is greater than the usage count a moment
before.
Switching the order in which the counts are read cannot help, so the thing to
do is to remove that particular check.
I had considered rechecking the values to see if they're in flux if the test
fails, but I can't guarantee they won't appear the same, even if they've
changed several times in the meantime.
Note that this can only happen if CONFIG_DEBUG_CREDENTIALS is enabled.
The problem is only likely to occur with multithreaded programs, and can be
tested by the tst-eintr1 program from glibc's "make check". The symptoms look
like:
CRED: Invalid credentials
CRED: At include/linux/cred.h:240
CRED: Specified credentials: ffff88003dda5878 [real][eff]
CRED: ->magic=43736564, put_addr=(null)
CRED: ->usage=766, subscr=766
CRED: ->*uid = { 0,0,0,0 }
CRED: ->*gid = { 0,0,0,0 }
CRED: ->security is ffff88003d72f538
CRED: ->security {359, 359}
------------[ cut here ]------------
kernel BUG at kernel/cred.c:850!
...
RIP: 0010:[<ffffffff81049889>] [<ffffffff81049889>] __invalid_creds+0x4e/0x52
...
Call Trace:
[<ffffffff8104a37b>] copy_creds+0x6b/0x23f
Note the ->usage=766 and subscr=766. The values appear the same because
they've been re-read since the check was made.
Reported-by: Roland McGrath <roland@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Patch 570b8fb505896e007fd3bb07573ba6640e51851d:
Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue Mar 30 00:04:00 2010 +0100
Subject: CRED: Fix memory leak in error handling
attempts to fix a memory leak in the error handling by making the offending
return statement into a jump down to the bottom of the function where a
kfree(tgcred) is inserted.
This is, however, incorrect, as it does a kfree() after doing put_cred() if
security_prepare_creds() fails. That will result in a double free if 'error'
is jumped to as put_cred() will also attempt to free the new tgcred record by
virtue of it being pointed to by the new cred record.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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The lockdep facility temporarily disables lockdep checking by
incrementing the current->lockdep_recursion variable. Such
disabling happens in NMIs and in other situations where lockdep
might expect to recurse on itself.
This patch therefore checks current->lockdep_recursion, disabling RCU
lockdep splats when this variable is non-zero. In addition, this patch
removes the "likely()", as suggested by Lai Jiangshan.
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Reported-by: David Miller <davem@davemloft.net>
Tested-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: eric.dumazet@gmail.com
LKML-Reference: <20100415195039.GA22623@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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When CONFIG_DEBUG_BLOCK_EXT_DEVT is set we decode the device
improperly by old_decode_dev and it results in an error while
hibernating with s2disk.
All users already pass the new device number, so switch to
new_decode_dev().
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-and-tested-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: "Rafael J. Wysocki" <rjw@sisk.pl>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: Fix sched_getaffinity()
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- We weren't zeroing p->rss_stat[] at fork()
- Consequently sync_mm_rss() was dereferencing tsk->mm for kernel
threads and was oopsing.
- Make __sync_task_rss_stat() static, too.
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=15648
[akpm@linux-foundation.org: remove the BUG_ON(!mm->rss)]
Reported-by: Troels Liebe Bentsen <tlb@rapanden.dk>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
"Michael S. Tsirkin" <mst@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
genirq: Force MSI irq handlers to run with interrupts disabled
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taskset on 2.6.34-rc3 fails on one of my ppc64 test boxes with
the following error:
sched_getaffinity(0, 16, 0x10029650030) = -1 EINVAL (Invalid argument)
This box has 128 threads and 16 bytes is enough to cover it.
Commit cd3d8031eb4311e516329aee03c79a08333141f1 (sched:
sched_getaffinity(): Allow less than NR_CPUS length) is
comparing this 16 bytes agains nr_cpu_ids.
Fix it by comparing nr_cpu_ids to the number of bits in the
cpumask we pass in.
Signed-off-by: Anton Blanchard <anton@samba.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Sharyathi Nagesh <sharyath@in.ibm.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Russ Anderson <rja@sgi.com>
Cc: Mike Travis <travis@sgi.com>
LKML-Reference: <20100406070218.GM5594@kryten>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Module refcounting is implemented with a per-cpu counter for speed.
However there is a race when tallying the counter where a reference may
be taken by one CPU and released by another. Reference count summation
may then see the decrement without having seen the previous increment,
leading to lower than expected count. A module which never has its
actual reference drop below 1 may return a reference count of 0 due to
this race.
Module removal generally runs under stop_machine, which prevents this
race causing bugs due to removal of in-use modules. However there are
other real bugs in module.c code and driver code (module_refcount is
exported) where the callers do not run under stop_machine.
Fix this by maintaining running per-cpu counters for the number of
module refcount increments and the number of refcount decrements. The
increments are tallied after the decrements, so any decrement seen will
always have its corresponding increment counted. The final refcount is
the difference of the total increments and decrements, preventing a
low-refcount from being returned.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There have been a number of reports of people seeing the message:
"name_count maxed, losing inode data: dev=00:05, inode=3185"
in dmesg. These usually lead to people reporting problems to the filesystem
group who are in turn clueless what they mean.
Eventually someone finds me and I explain what is going on and that
these come from the audit system. The basics of the problem is that the
audit subsystem never expects a single syscall to 'interact' (for some
wish washy meaning of interact) with more than 20 inodes. But in fact
some operations like loading kernel modules can cause changes to lots of
inodes in debugfs.
There are a couple real fixes being bandied about including removing the
fixed compile time limit of 20 or not auditing changes in debugfs (or
both) but neither are small and obvious so I am not sending them for
immediate inclusion (I hope Al forwards a real solution next devel
window).
In the meantime this patch simply adds 'audit' to the beginning of the
crap message so if a user sees it, they come blame me first and we can
talk about what it means and make sure we understand all of the reasons
it can happen and make sure this gets solved correctly in the long run.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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* 'slabh' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc:
eeepc-wmi: include slab.h
staging/otus: include slab.h from usbdrv.h
percpu: don't implicitly include slab.h from percpu.h
kmemcheck: Fix build errors due to missing slab.h
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
iwlwifi: don't include iwl-dev.h from iwl-devtrace.h
x86: don't include slab.h from arch/x86/include/asm/pgtable_32.h
Fix up trivial conflicts in include/linux/percpu.h due to
is_kernel_percpu_address() having been introduced since the slab.h
cleanup with the percpu_up.c splitup.
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
module: add stub for is_module_percpu_address
percpu, module: implement and use is_kernel/module_percpu_address()
module: encapsulate percpu handling better and record percpu_size
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf: Always build the powerpc perf_arch_fetch_caller_regs version
perf: Always build the stub perf_arch_fetch_caller_regs version
perf, probe-finder: Build fix on Debian
perf/scripts: Tuple was set from long in both branches in python_process_event()
perf: Fix 'perf sched record' deadlock
perf, x86: Fix callgraphs of 32-bit processes on 64-bit kernels
perf, x86: Fix AMD hotplug & constraint initialization
x86: Move notify_cpu_starting() callback to a later stage
x86,kgdb: Always initialize the hw breakpoint attribute
perf: Use hot regs with software sched switch/migrate events
perf: Correctly align perf event tracing buffer
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: set_cpus_allowed_ptr(): Don't use rq->migration_thread after unlock
sched: Fix proc_sched_set_task()
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
ring-buffer: Add missing unlock
tracing: Fix lockdep warning in global_clock()
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Now that software events use perf_arch_fetch_caller_regs() too, we
need the stub version to be always built in for archs that don't
implement it.
Fixes the following build error in PARISC:
kernel/built-in.o: In function `perf_event_task_sched_out':
(.text.perf_event_task_sched_out+0x54): undefined reference to `perf_arch_fetch_caller_regs'
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb
* 'kgdb-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
kgdb: Turn off tracing while in the debugger
kgdb: use atomic_inc and atomic_dec instead of atomic_set
kgdb: eliminate kgdb_wait(), all cpus enter the same way
kgdbts,sh: Add in breakpoint pc offset for superh
kgdb: have ebin2mem call probe_kernel_write once
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6
* 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
Freezer: Fix buggy resume test for tasks frozen with cgroup freezer
Freezer: Only show the state of tasks refusing to freeze
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The kernel debugger should turn off kernel tracing any time the
debugger is active and restore it on resume.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
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Memory barriers should be used for the kgdb cpu synchronization. The
atomic_set() does not imply a memory barrier.
Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
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This is a kgdb architectural change to have all the cpus (master or
slave) enter the same function.
A cpu that hits an exception (wants to be the master cpu) will call
kgdb_handle_exception() from the trap handler and then invoke a
kgdb_roundup_cpu() to synchronize the other cpus and bring them into
the kgdb_handle_exception() as well.
A slave cpu will enter kgdb_handle_exception() from the
kgdb_nmicallback() and set the exception state to note that the
processor is a slave.
Previously the salve cpu would have called kgdb_wait(). This change
allows the debug core to change cpus without resuming the system in
order to inspect arch specific cpu information.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
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Rather than call probe_kernel_write() one byte at a time, process the
whole buffer locally and pass the entire result in one go. This way,
architectures that need to do special handling based on the length can
do so, or we only end up calling memcpy() once.
[sonic.zhang@analog.com: Reported original problem and preliminary patch]
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
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Trivial typo fix. rq->migration_thread can be NULL after
task_rq_unlock(), this is why we have "mt" which should be
used instead.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100330165829.GA18284@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Latencytop clearing sum_exec_runtime via proc_sched_set_task() breaks
task_times(). Other places in kernel use nvcsw and nivcsw, which are
being cleared as well, Clear task statistics only.
Reported-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1269940193.19286.14.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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perf sched record can deadlock a box should the holder of
handle->data->lock take an interrupt, and then attempt to
acquire an rq lock held by a CPU trying to acquire the
same lock. Disable interrupts.
CPU0 CPU1
sched event with rq->lock held
grab handle->data->lock
spin on handle->data->lock
interrupt
try to grab rq->lock
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Tested-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1269598293.6174.8.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/urgent
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Scheduler's task migration events don't work because they always
pass NULL regs perf_sw_event(). The event hence gets filtered
in perf_swevent_add().
Scheduler's context switches events use task_pt_regs() to get
the context when the event occured which is a wrong thing to
do as this won't give us the place in the kernel where we went
to sleep but the place where we left userspace. The result is
even more wrong if we switch from a kernel thread.
Use the hot regs snapshot for both events as they belong to the
non-interrupt/exception based events family. Unlike page faults
or so that provide the regs matching the exact origin of the event,
we need to save the current context.
This makes the task migration event working and fix the context
switch callchains and origin ip.
Example: perf record -a -e cs
Before:
10.91% ksoftirqd/0 0 [k] 0000000000000000
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--- (nil)
perf_callchain
perf_prepare_sample
__perf_event_overflow
perf_swevent_overflow
perf_swevent_add
perf_swevent_ctx_event
do_perf_sw_event
__perf_sw_event
perf_event_task_sched_out
schedule
run_ksoftirqd
kthread
kernel_thread_helper
After:
23.77% hald-addon-stor [kernel.kallsyms] [k] schedule
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--- schedule
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|--60.00%-- schedule_timeout
| wait_for_common
| wait_for_completion
| blk_execute_rq
| scsi_execute
| scsi_execute_req
| sr_test_unit_ready
| |
| |--66.67%-- sr_media_change
| | media_changed
| | cdrom_media_changed
| | sr_block_media_changed
| | check_disk_change
| | cdrom_open
v2: Always build perf_arch_fetch_caller_regs() now that software
events need that too. They don't need it from modules, unlike trace
events, so we keep the EXPORT_SYMBOL in trace_event_perf.c
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
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The trace event buffer used by perf to record raw sample events
is typed as an array of char and may then not be aligned to 8
by alloc_percpu().
But we need it to be aligned to 8 in sparc64 because we cast
this buffer into a random structure type built by the TRACE_EVENT()
macro to store the traces. So if a random 64 bits field is accessed
inside, it may be not under an expected good alignment.
Use an array of long instead to force the appropriate alignment, and
perform a compile time check to ensure the size in byte of the buffer
is a multiple of sizeof(long) so that its actual size doesn't get
shrinked under us.
This fixes unaligned accesses reported while using perf lock
in sparc 64.
Suggested-by: David Miller <davem@davemloft.net>
Suggested-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
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Network folks reported that directing all MSI-X vectors of their multi
queue NICs to a single core can cause interrupt stack overflows when
enough interrupts fire at the same time.
This is caused by the fact that we run interrupt handlers by default
with interrupts enabled unless the driver reuqests the interrupt with
the IRQF_DISABLED set. The NIC handlers do not set this flag, so
simultaneous interrupts can nest unlimited and cause the stack
overflow.
The only safe counter measure is to run the interrupt handlers with
interrupts disabled. We can't switch to this mode in general right
now, but it is safe to do so for MSI interrupts.
Force IRQF_DISABLED for MSI interrupt handlers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Linus Torvalds <torvalds@osdl.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: stable@kernel.org
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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
CRED: Fix memory leak in error handling
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Do not free zero sized per cpu areas
x86: Make sure free_init_pages() frees pages on page boundary
x86: Make smp_locks end with page alignment
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implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
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Fix a memory leak on an OOM condition in prepare_usermodehelper_creds().
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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In some error handling cases the lock is not unlocked. The return is
converted to a goto, to share the unlock at the end of the function.
A simplified version of the semantic patch that finds this problem is as
follows: (http://coccinelle.lip6.fr/)
// <smpl>
@r exists@
expression E1;
identifier f;
@@
f (...) { <+...
* spin_lock_irq (E1,...);
... when != E1
* return ...;
...+> }
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
LKML-Reference: <Pine.LNX.4.64.1003291736440.21896@ask.diku.dk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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# echo 1 > events/enable
# echo global > trace_clock
------------[ cut here ]------------
WARNING: at kernel/lockdep.c:3162 check_flags+0xb2/0x190()
...
---[ end trace 3f86734a89416623 ]---
possible reason: unannotated irqs-on.
...
There's no reason to use the raw_local_irq_save() in trace_clock_global.
The local_irq_save() version is fine, and does not cause the bug in lockdep.
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4BA97FA1.7030606@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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