ab657a29c3
commit c0226eb8bde854e016a594a16f5c0d98aca426fa upstream.
Check lru_cache_disabled under bh_lru_lock. Otherwise, it could introduce
race below and it fails to migrate pages containing buffer_head.
CPU 0 CPU 1
bh_lru_install
lru_cache_disable
lru_cache_disabled = false
atomic_inc(&lru_disable_count);
invalidate_bh_lrus_cpu of CPU 0
bh_lru_lock
__invalidate_bh_lrus
bh_lru_unlock
bh_lru_lock
install the bh
bh_lru_unlock
WHen this race happens a CMA allocation fails, which is critical for
the workload which depends on CMA.
Link: https://lkml.kernel.org/r/20220308180709.2017638-1-minchan@kernel.org
Fixes: 8cc621d2f45d ("mm: fs: invalidate BH LRU during page migration")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Chris Goldsworthy <cgoldswo@codeaurora.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: John Dias <joaodias@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
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