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author | Tejun Heo <tj@kernel.org> | 2011-04-29 16:08:37 (GMT) |
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committer | Tejun Heo <tj@kernel.org> | 2011-04-29 16:08:37 (GMT) |
commit | 5035b20fa5cd146b66f5f89619c20a4177fb736d (patch) | |
tree | cd62bba3a3c36164d0faaac1b3c922be0eca11f1 /Documentation | |
parent | e2de9e0862778f4aba103027ce575efbddb8117f (diff) | |
download | linux-fsl-qoriq-5035b20fa5cd146b66f5f89619c20a4177fb736d.tar.xz |
workqueue: fix deadlock in worker_maybe_bind_and_lock()
If a rescuer and stop_machine() bringing down a CPU race with each
other, they may deadlock on non-preemptive kernel. The CPU won't
accept a new task, so the rescuer can't migrate to the target CPU,
while stop_machine() can't proceed because the rescuer is holding one
of the CPU retrying migration. GCWQ_DISASSOCIATED is never cleared
and worker_maybe_bind_and_lock() retries indefinitely.
This problem can be reproduced semi reliably while the system is
entering suspend.
http://thread.gmane.org/gmane.linux.kernel/1122051
A lot of kudos to Thilo-Alexander for reporting this tricky issue and
painstaking testing.
stable: This affects all kernels with cmwq, so all kernels since and
including v2.6.36 need this fix.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Thilo-Alexander Ginkel <thilo@ginkel.com>
Tested-by: Thilo-Alexander Ginkel <thilo@ginkel.com>
Cc: stable@kernel.org
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions