6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jens Axboe axboe@kernel.dk
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 --- io_uring/io_uring.c | 53 +++++++++++++++------------------------------------- 1 file changed, 16 insertions(+), 37 deletions(-)
--- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -422,24 +422,6 @@ static struct io_kiocb *__io_prep_linked 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
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_kioc
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_kio 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 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 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 i 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_kio 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 i * 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); }