diff options
| author | Bart Van Assche <bvanassche@acm.org> | 2020-03-09 21:26:18 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-03-10 07:09:59 -0600 |
| commit | d0930bb8f46b8fb4a7d429c0bf1c91b3ed00a7cf (patch) | |
| tree | 698686cf841670bf3de44b08bf5e8062f6d95592 /block/blk-mq.c | |
| parent | 6e66b49392419f3fe134e1be583323ef75da1e4b (diff) | |
blk-mq: Fix a recently introduced regression in blk_mq_realloc_hw_ctxs()
q->nr_hw_queues must only be updated once it is known that
blk_mq_realloc_hw_ctxs() has succeeded. Otherwise it can happen that
reallocation fails and that q->nr_hw_queues is larger than the number of
allocated hardware queues. This patch fixes the following crash if
increasing the number of hardware queues fails:
BUG: KASAN: null-ptr-deref in blk_mq_map_swqueue+0x775/0x810
Write of size 8 at addr 0000000000000118 by task check/977
CPU: 3 PID: 977 Comm: check Not tainted 5.6.0-rc1-dbg+ #8
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Call Trace:
dump_stack+0xa5/0xe6
__kasan_report.cold+0x65/0x99
kasan_report+0x16/0x20
check_memory_region+0x140/0x1b0
memset+0x28/0x40
blk_mq_map_swqueue+0x775/0x810
blk_mq_update_nr_hw_queues+0x468/0x710
nullb_device_submit_queues_store+0xf7/0x1a0 [null_blk]
configfs_write_file+0x1c4/0x250 [configfs]
__vfs_write+0x4c/0x90
vfs_write+0x145/0x2c0
ksys_write+0xd7/0x180
__x64_sys_write+0x47/0x50
do_syscall_64+0x6f/0x2f0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fixes: ac0d6b926e74 ("block: Reduce the amount of memory required per request queue")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Johannes Thumshirn <jth@kernel.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq.c')
| -rw-r--r-- | block/blk-mq.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index d4bd9b961726..37ff8dfb8ab9 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2824,7 +2824,6 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, memcpy(new_hctxs, hctxs, q->nr_hw_queues * sizeof(*hctxs)); q->queue_hw_ctx = new_hctxs; - q->nr_hw_queues = set->nr_hw_queues; kfree(hctxs); hctxs = new_hctxs; } |