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authorDaniel Jordan <daniel.m.jordan@oracle.com>2019-12-03 14:31:11 -0500
committerHerbert Xu <herbert@gondor.apana.org.au>2019-12-11 16:37:02 +0800
commit38228e8848cd7dd86ccb90406af32de0cad24be3 (patch)
treef1d28cac2721992aabffe310f29e60551f84c3c2 /include/linux/padata.h
parentpadata: validate cpumask without removed CPU during offline (diff)
downloadlinux-dev-38228e8848cd7dd86ccb90406af32de0cad24be3.tar.xz
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padata: always acquire cpu_hotplug_lock before pinst->lock
lockdep complains when padata's paths to update cpumasks via CPU hotplug and sysfs are both taken: # echo 0 > /sys/devices/system/cpu/cpu1/online # echo ff > /sys/kernel/pcrypt/pencrypt/parallel_cpumask ====================================================== WARNING: possible circular locking dependency detected 5.4.0-rc8-padata-cpuhp-v3+ #1 Not tainted ------------------------------------------------------ bash/205 is trying to acquire lock: ffffffff8286bcd0 (cpu_hotplug_lock.rw_sem){++++}, at: padata_set_cpumask+0x2b/0x120 but task is already holding lock: ffff8880001abfa0 (&pinst->lock){+.+.}, at: padata_set_cpumask+0x26/0x120 which lock already depends on the new lock. padata doesn't take cpu_hotplug_lock and pinst->lock in a consistent order. Which should be first? CPU hotplug calls into padata with cpu_hotplug_lock already held, so it should have priority. Fixes: 6751fb3c0e0c ("padata: Use get_online_cpus/put_online_cpus") Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'include/linux/padata.h')
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