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| author | Christoph Lameter <cl@linux.com> | 2014-04-07 15:39:39 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-07 16:36:14 -0700 |
| commit | 08f141d3dbddacb70aba1541bc5f950e466591e9 (patch) | |
| tree | b704102a5660c8e61ca91b6f6059d72bb95330f9 /kernel | |
| parent | dc322a99d31fff5d3f8acfa061ad033953efdebe (diff) | |
| download | lwn-08f141d3dbddacb70aba1541bc5f950e466591e9.tar.gz lwn-08f141d3dbddacb70aba1541bc5f950e466591e9.zip | |
modules: use raw_cpu_write for initialization of per cpu refcount.
The initialization of a structure is not subject to synchronization.
The use of __this_cpu would trigger a false positive with the additional
preemption checks for __this_cpu ops.
So simply disable the check through the use of raw_cpu ops.
Trace:
__this_cpu_write operation in preemptible [00000000] code: modprobe/286
caller is __this_cpu_preempt_check+0x38/0x60
CPU: 3 PID: 286 Comm: modprobe Tainted: GF 3.12.0-rc4+ #187
Call Trace:
dump_stack+0x4e/0x82
check_preemption_disabled+0xec/0x110
__this_cpu_preempt_check+0x38/0x60
load_module+0xcfd/0x2650
SyS_init_module+0xa6/0xd0
tracesys+0xe1/0xe6
Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/module.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/module.c b/kernel/module.c index 29f7790eaa14..11869408f79b 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -640,7 +640,7 @@ static int module_unload_init(struct module *mod) INIT_LIST_HEAD(&mod->target_list); /* Hold reference count during initialization. */ - __this_cpu_write(mod->refptr->incs, 1); + raw_cpu_write(mod->refptr->incs, 1); return 0; } |