path: root/block/blk-merge.c
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authorSam Bradshaw <sbradshaw@micron.com>2015-03-18 17:06:18 -0600
committerJens Axboe <axboe@fb.com>2015-03-18 17:06:18 -0600
commitbc188d818edf325ae38cfa43254a0b10a4defd65 (patch)
tree08dec19e40bccd2d87738686f94c15e31d121c67 /block/blk-merge.c
parent9a30b096b543932de218dd3501b5562e00a8792d (diff)
blkmq: Fix NULL pointer deref when all reserved tags in
When allocating from the reserved tags pool, bt_get() is called with a NULL hctx. If all tags are in use, the hw queue is kicked to push out any pending IO, potentially freeing tags, and tag allocation is retried. The problem is that blk_mq_run_hw_queue() doesn't check for a NULL hctx. So we avoid it with a simple NULL hctx test. Tested by hammering mtip32xx with concurrent smartctl/hdparm. Signed-off-by: Sam Bradshaw <sbradshaw@micron.com> Signed-off-by: Selvan Mani <smani@micron.com> Fixes: b32232073e80 ("blk-mq: fix hang in bt_get()") Cc: stable@kernel.org Added appropriate comment. Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-merge.c')
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