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io_uring: always arm linked timeouts prior to issue

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Commit b53e523261bf058ea4a518b482222e7a277b186b upstream.

There are a few spots where linked timeouts are armed, and not all of
them adhere to the pre-arm, attempt issue, post-arm pattern. This can
be problematic if the linked request returns that it will trigger a
callback later, and does so before the linked timeout is fully armed.

Consolidate all the linked timeout handling into __io_issue_sqe(),
rather than have it spread throughout the various issue entry points.

Cc: stable@vger.kernel.org
Link: https://github.com/axboe/liburing/issues/1390
Reported-by: Chase Hiltz <chase@path.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jens Axboe
2025-05-05 08:34:39 -06:00
committed by Greg Kroah-Hartman
parent 00f0dd1a01
commit 51f1389b5f
1 changed files with 16 additions and 37 deletions
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53
io_uring/io_uring.c
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@@ -422,24 +422,6 @@ static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
return req->link;
}
static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
{
if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT)))
return NULL;
return __io_prep_linked_timeout(req);
}
static noinline void __io_arm_ltimeout(struct io_kiocb *req)
{
io_queue_linked_timeout(__io_prep_linked_timeout(req));
}
static inline void io_arm_ltimeout(struct io_kiocb *req)
{
if (unlikely(req->flags & REQ_F_ARM_LTIMEOUT))
__io_arm_ltimeout(req);
}
static void io_prep_async_work(struct io_kiocb *req)
{
const struct io_issue_def *def = &io_issue_defs[req->opcode];
@@ -493,7 +475,6 @@ static void io_prep_async_link(struct io_kiocb *req)
static void io_queue_iowq(struct io_kiocb *req)
{
struct io_kiocb *link = io_prep_linked_timeout(req);
struct io_uring_task *tctx = req->task->io_uring;
BUG_ON(!tctx);
@@ -518,8 +499,6 @@ static void io_queue_iowq(struct io_kiocb *req)
trace_io_uring_queue_async_work(req, io_wq_is_hashed(&req->work));
io_wq_enqueue(tctx->io_wq, &req->work);
if (link)
io_queue_linked_timeout(link);
}
static __cold void io_queue_deferred(struct io_ring_ctx *ctx)
@@ -1863,17 +1842,24 @@ static bool io_assign_file(struct io_kiocb *req, const struct io_issue_def *def,
return !!req->file;
}
#define REQ_ISSUE_SLOW_FLAGS (REQ_F_CREDS | REQ_F_ARM_LTIMEOUT)
static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
{
const struct io_issue_def *def = &io_issue_defs[req->opcode];
const struct cred *creds = NULL;
struct io_kiocb *link = NULL;
int ret;
if (unlikely(!io_assign_file(req, def, issue_flags)))
return -EBADF;
if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred()))
creds = override_creds(req->creds);
if (unlikely(req->flags & REQ_ISSUE_SLOW_FLAGS)) {
if ((req->flags & REQ_F_CREDS) && req->creds != current_cred())
creds = override_creds(req->creds);
if (req->flags & REQ_F_ARM_LTIMEOUT)
link = __io_prep_linked_timeout(req);
}
if (!def->audit_skip)
audit_uring_entry(req->opcode);
@@ -1883,8 +1869,12 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
if (!def->audit_skip)
audit_uring_exit(!ret, ret);
if (creds)
revert_creds(creds);
if (unlikely(creds || link)) {
if (creds)
revert_creds(creds);
if (link)
io_queue_linked_timeout(link);
}
if (ret == IOU_OK) {
if (issue_flags & IO_URING_F_COMPLETE_DEFER)
@@ -1939,8 +1929,6 @@ void io_wq_submit_work(struct io_wq_work *work)
else
req_ref_get(req);
io_arm_ltimeout(req);
/* either cancelled or io-wq is dying, so don't touch tctx->iowq */
if (work->flags & IO_WQ_WORK_CANCEL) {
fail:
@@ -2036,15 +2024,11 @@ struct file *io_file_get_normal(struct io_kiocb *req, int fd)
static void io_queue_async(struct io_kiocb *req, int ret)
__must_hold(&req->ctx->uring_lock)
{
struct io_kiocb *linked_timeout;
if (ret != -EAGAIN || (req->flags & REQ_F_NOWAIT)) {
io_req_defer_failed(req, ret);
return;
}
linked_timeout = io_prep_linked_timeout(req);
switch (io_arm_poll_handler(req, 0)) {
case IO_APOLL_READY:
io_kbuf_recycle(req, 0);
@@ -2057,9 +2041,6 @@ static void io_queue_async(struct io_kiocb *req, int ret)
case IO_APOLL_OK:
break;
}
if (linked_timeout)
io_queue_linked_timeout(linked_timeout);
}
static inline void io_queue_sqe(struct io_kiocb *req)
@@ -2073,9 +2054,7 @@ static inline void io_queue_sqe(struct io_kiocb *req)
* We async punt it if the file wasn't marked NOWAIT, or if the file
* doesn't support non-blocking read/write attempts
*/
if (likely(!ret))
io_arm_ltimeout(req);
else
if (unlikely(ret))
io_queue_async(req, ret);
}