diff options
| author | Nilay Shroff <nilay@linux.ibm.com> | 2025-03-13 17:21:52 +0530 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-03-13 07:23:43 -0600 |
| commit | 0e94ed33681424a6dce65c62837e08e4c7aa09ac (patch) | |
| tree | cb95082667f464c5bd14eed5af97b99d0c83e7e1 /block | |
| parent | 78800f5997d8ae0f20d4aced66a524f0f2fc4c7f (diff) | |
block: protect debugfs attribute method hctx_busy_show
The hctx_busy_show method in debugfs is currently unprotected. This
method iterates over all started requests in a tagset and prints them.
However, the tags can be updated concurrently via the sysfs attributes
'nr_requests' or 'scheduler' (elevator switch), leading to potential
race conditions.
Since sysfs attributes 'nr_requests' and 'scheduler' are already
protected using q->elevator_lock, extend this protection to the debugfs
'busy' attribute as well to ensure consistency.
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250313115235.3707600-4-nilay@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-mq-debugfs.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index 1c958bbaddce..3421b5521fe2 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -347,9 +347,14 @@ static int hctx_busy_show(void *data, struct seq_file *m) { struct blk_mq_hw_ctx *hctx = data; struct show_busy_params params = { .m = m, .hctx = hctx }; + int res; + res = mutex_lock_interruptible(&hctx->queue->elevator_lock); + if (res) + return res; blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq, ¶ms); + mutex_unlock(&hctx->queue->elevator_lock); return 0; } |