The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x b53e523261bf058ea4a518b482222e7a277b186b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025051225-punisher-evident-a1a8@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From b53e523261bf058ea4a518b482222e7a277b186b Mon Sep 17 00:00:00 2001 From: Jens Axboe axboe@kernel.dk Date: Sun, 4 May 2025 08:06:28 -0600 Subject: [PATCH] io_uring: always arm linked timeouts prior to issue
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
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index a2b256e96d5d..769814d71153 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -448,24 +448,6 @@ 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]; @@ -518,7 +500,6 @@ 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->tctx;
BUG_ON(!tctx); @@ -543,8 +524,6 @@ 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 void io_req_queue_iowq_tw(struct io_kiocb *req, io_tw_token_t tw) @@ -1724,15 +1703,22 @@ 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 inline int __io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags, const struct io_issue_def *def) { const struct cred *creds = NULL; + struct io_kiocb *link = NULL; int ret;
- 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); @@ -1742,8 +1728,12 @@ static inline int __io_issue_sqe(struct io_kiocb *req, 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); + }
return ret; } @@ -1769,7 +1759,6 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
if (ret == IOU_ISSUE_SKIP_COMPLETE) { ret = 0; - io_arm_ltimeout(req);
/* If the op doesn't have a file, we're not polling for it */ if ((req->ctx->flags & IORING_SETUP_IOPOLL) && def->iopoll_queue) @@ -1824,8 +1813,6 @@ 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 (atomic_read(&work->flags) & IO_WQ_WORK_CANCEL) { fail: @@ -1941,15 +1928,11 @@ 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); @@ -1962,9 +1945,6 @@ 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)