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author | Mikulas Patocka <mpatocka@redhat.com> | 2021-02-10 23:26:23 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-04 13:38:44 +0300 |
commit | 1f145073b196073891d2df66d2d011f1c361fd26 (patch) | |
tree | def75b993ad1e08db56c7d670735da1c3e9840fa /drivers/md/dm-table.c | |
parent | eb8128c5bb7f03541515fb90364ca5d488eb901c (diff) | |
download | linux-1f145073b196073891d2df66d2d011f1c361fd26.tar.xz |
dm: fix deadlock when swapping to encrypted device
commit a666e5c05e7c4aaabb2c5d58117b0946803d03d2 upstream.
The system would deadlock when swapping to a dm-crypt device. The reason
is that for each incoming write bio, dm-crypt allocates memory that holds
encrypted data. These excessive allocations exhaust all the memory and the
result is either deadlock or OOM trigger.
This patch limits the number of in-flight swap bios, so that the memory
consumed by dm-crypt is limited. The limit is enforced if the target set
the "limit_swap_bios" variable and if the bio has REQ_SWAP set.
Non-swap bios are not affected becuase taking the semaphore would cause
performance degradation.
This is similar to request-based drivers - they will also block when the
number of requests is over the limit.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/md/dm-table.c')
0 files changed, 0 insertions, 0 deletions