Commit 22cad158 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe

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: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 8e2e1faf
......@@ -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)
......
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