diff options
| author | Steven Rostedt <rostedt@goodmis.org> | 2011-10-11 23:56:23 -0400 |
|---|---|---|
| committer | Clark Williams <williams@redhat.com> | 2012-03-24 10:26:27 -0500 |
| commit | 61aadd04603c46cec11a6c0178854d643cbadadd (patch) | |
| tree | 5fe8785c682d3a5c07105b3c055c7e961327bebb /mm | |
| parent | 45c60a2bd73b920e0c96062e756b17831b3d6731 (diff) | |
slab: Fix __do_drain to use the right array cache
The array cache in __do_drain() was using the cpu_cache_get() function
which uses smp_processor_id() to get the proper array. On mainline, this
is fine as __do_drain() is called by for_each_cpu() which runs
__do_drain() on the CPU it is processing. In RT locks are used instead
and __do_drain() is only called from a single CPU. This can cause the
accounting to be off and trigger the following bug:
slab error in kmem_cache_destroy(): cache `nfs_write_data': Can't free all objects
Pid: 2905, comm: rmmod Not tainted 3.0.6-test-rt17+ #78
Call Trace:
[<ffffffff810fb623>] kmem_cache_destroy+0xa0/0xdf
[<ffffffffa03aaffb>] nfs_destroy_writepagecache+0x49/0x4e [nfs]
[<ffffffffa03c0fe0>] exit_nfs_fs+0xe/0x46 [nfs]
[<ffffffff8107af09>] sys_delete_module+0x1ba/0x22c
[<ffffffff8109429d>] ? audit_syscall_entry+0x11c/0x148
[<ffffffff814b6442>] system_call_fastpath+0x16/0x1b
This can be easily triggered by a simple while loop:
# while :; do modprobe nfs; rmmod nfs; done
The proper function to use is cpu_cache_get_on_cpu(). It works for both
RT and non-RT as the non-RT passes in smp_processor_id() into
__do_drain().
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Clark Williams <clark@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1318391783.13262.11.camel@gandalf.stny.rr.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/slab.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/slab.c b/mm/slab.c index 38575a8dcf7a..5b6314857778 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2573,7 +2573,7 @@ static void __do_drain(void *arg, unsigned int cpu) struct array_cache *ac; int node = cpu_to_mem(cpu); - ac = cpu_cache_get(cachep); + ac = cpu_cache_get_on_cpu(cachep, cpu); spin_lock(&cachep->nodelists[node]->list_lock); free_block(cachep, ac->entry, ac->avail, node); spin_unlock(&cachep->nodelists[node]->list_lock); |