diff options
| author | Pavel Begunkov | 2020-04-15 00:39:48 +0300 |
|---|---|---|
| committer | Jens Axboe | 2020-04-14 19:16:55 -0600 |
| commit | 22cad1585c6bc6caf2688701004cf2af6865cbe0 (patch) | |
| tree | fe6b0e574f15fd5d6fb27bf009e8bf0020e95023 /fs/io_uring.c | |
| parent | 8e2e1faf28b3e66430f55f0b0ee83370ecc150af (diff) | |
io_uring: fix cached_sq_head in io_timeout()
io_timeout() can be executed asynchronously by a worker and without
holding ctx->uring_lock
1. using ctx->cached_sq_head there is racy there
2. it should count events from a moment of timeout's submission, but
not execution
Use req->sequence.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
| -rw-r--r-- | fs/io_uring.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 32cbace58256..9325ac618cf0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4714,6 +4714,7 @@ static int io_timeout(struct io_kiocb *req) struct io_timeout_data *data; struct list_head *entry; unsigned span = 0; + u32 seq = req->sequence; data = &req->io->timeout; @@ -4730,7 +4731,7 @@ static int io_timeout(struct io_kiocb *req) goto add; } - req->sequence = ctx->cached_sq_head + count - 1; + req->sequence = seq + count; data->seq_offset = count; /* @@ -4740,7 +4741,7 @@ static int io_timeout(struct io_kiocb *req) spin_lock_irq(&ctx->completion_lock); list_for_each_prev(entry, &ctx->timeout_list) { struct io_kiocb *nxt = list_entry(entry, struct io_kiocb, list); - unsigned nxt_sq_head; + unsigned nxt_seq; long long tmp, tmp_nxt; u32 nxt_offset = nxt->io->timeout.seq_offset; @@ -4748,18 +4749,18 @@ static int io_timeout(struct io_kiocb *req) continue; /* - * Since cached_sq_head + count - 1 can overflow, use type long + * Since seq + count can overflow, use type long * long to store it. */ - tmp = (long long)ctx->cached_sq_head + count - 1; - nxt_sq_head = nxt->sequence - nxt_offset + 1; - tmp_nxt = (long long)nxt_sq_head + nxt_offset - 1; + tmp = (long long)seq + count; + nxt_seq = nxt->sequence - nxt_offset; + tmp_nxt = (long long)nxt_seq + nxt_offset; /* * cached_sq_head may overflow, and it will never overflow twice * once there is some timeout req still be valid. */ - if (ctx->cached_sq_head < nxt_sq_head) + if (seq < nxt_seq) tmp += UINT_MAX; if (tmp > tmp_nxt) |