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author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2013-07-24 18:31:42 +0800 |
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committer | Tejun Heo <tj@kernel.org> | 2013-07-24 12:24:25 -0400 |
commit | c2fda509667b0fda4372a237f5a59ea4570b1627 (patch) | |
tree | 27ba4e2f32cdd58e2f6f2cfa694f25afe7020e35 /sound/ppc | |
parent | ad81f0545ef01ea651886dddac4bef6cec930092 (diff) | |
download | kernel_goldelico_gta04-c2fda509667b0fda4372a237f5a59ea4570b1627.zip kernel_goldelico_gta04-c2fda509667b0fda4372a237f5a59ea4570b1627.tar.gz kernel_goldelico_gta04-c2fda509667b0fda4372a237f5a59ea4570b1627.tar.bz2 |
workqueue: allow work_on_cpu() to be called recursively
If the @fn call work_on_cpu() again, the lockdep will complain:
> [ INFO: possible recursive locking detected ]
> 3.11.0-rc1-lockdep-fix-a #6 Not tainted
> ---------------------------------------------
> kworker/0:1/142 is trying to acquire lock:
> ((&wfc.work)){+.+.+.}, at: [<ffffffff81077100>] flush_work+0x0/0xb0
>
> but task is already holding lock:
> ((&wfc.work)){+.+.+.}, at: [<ffffffff81075dd9>] process_one_work+0x169/0x610
>
> other info that might help us debug this:
> Possible unsafe locking scenario:
>
> CPU0
> ----
> lock((&wfc.work));
> lock((&wfc.work));
>
> *** DEADLOCK ***
It is false-positive lockdep report. In this sutiation,
the two "wfc"s of the two work_on_cpu() are different,
they are both on stack. flush_work() can't be deadlock.
To fix this, we need to avoid the lockdep checking in this case,
thus we instroduce a internal __flush_work() which skip the lockdep.
tj: Minor comment adjustment.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reported-by: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Reported-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'sound/ppc')
0 files changed, 0 insertions, 0 deletions