6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josef Bacik Commit e1a64bc64897f4c2fe460922c345f2ed8f889b5f upstream. -ERESTARTSYS and friends are instructions for the system call exit code, which either restarts the call or turns them into -EINTR. They are not supposed to be seen by applications. A request isn't a system call, nobody looks at what it returns before that is put into a CQE. The read/write and the networking opcodes convert these codes to -EINTR by hand. The others don't. An io-wq worker that is blocked in the open of a FIFO, a tty or some other device, or in a splice from an empty pipe, and that gets interrupted because the request is cancelled, completes it with -512: IORING_OP_OPENAT, IOSQE_ASYNC // FIFO without a writer IORING_OP_ASYNC_CANCEL // -EALREADY, worker is signalled CQE of the open: res == -512 There are more candidates, like whatever a file system or driver returns from ->flush(), ->fsync(), ->fallocate() or ->uring_cmd(), or breaking a lease or delegation. Take care of it in io_issue_sqe(), which all of them go through. The helper is moved from rw.c as is. The cost is a compare and a branch that is not taken per request. Fixes: 15b71abe7b52 ("io_uring: add support for IORING_OP_OPENAT") Assisted-by: LLM Signed-off-by: Josef Bacik Link: https://patch.msgid.link/20261015-b4-io-uring-fixes-v1-39-c1556f5d7bf5@toxicpanda.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- io_uring/io_uring.c | 5 +++++ io_uring/io_uring.h | 18 ++++++++++++++++++ io_uring/rw.c | 18 ------------------ 3 files changed, 23 insertions(+), 18 deletions(-) --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1773,6 +1773,9 @@ static int io_issue_sqe(struct io_kiocb } if (ret == IOU_OK) { + /* not all handlers take care of the internal restart codes */ + if (unlikely(req->cqe.res <= -ERESTARTSYS)) + req->cqe.res = io_fixup_restart_res(req->cqe.res); if (issue_flags & IO_URING_F_COMPLETE_DEFER) io_req_complete_defer(req); else @@ -1788,6 +1791,8 @@ static int io_issue_sqe(struct io_kiocb if ((req->ctx->flags & IORING_SETUP_IOPOLL) && def->iopoll_queue) io_iopoll_req_issued(req, issue_flags); } + if (unlikely(ret <= -ERESTARTSYS)) + ret = io_fixup_restart_res(ret); return ret; } --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -203,6 +203,24 @@ static __always_inline bool io_fill_cqe_ return true; } +static inline ssize_t io_fixup_restart_res(ssize_t ret) +{ + switch (ret) { + case -ERESTARTSYS: + case -ERESTARTNOINTR: + case -ERESTARTNOHAND: + case -ERESTART_RESTARTBLOCK: + /* + * We can't just restart the syscall, since previously + * submitted sqes may already be in progress. Just fail + * this IO with EINTR. + */ + return -EINTR; + default: + return ret; + } +} + static inline void req_set_fail(struct io_kiocb *req) { req->flags |= REQ_F_FAIL; --- a/io_uring/rw.c +++ b/io_uring/rw.c @@ -560,24 +560,6 @@ static void io_complete_rw_iopoll(struct smp_store_release(&req->iopoll_completed, 1); } -static inline ssize_t io_fixup_restart_res(ssize_t ret) -{ - switch (ret) { - case -ERESTARTSYS: - case -ERESTARTNOINTR: - case -ERESTARTNOHAND: - case -ERESTART_RESTARTBLOCK: - /* - * We can't just restart the syscall, since previously - * submitted sqes may already be in progress. Just fail - * this IO with EINTR. - */ - return -EINTR; - default: - return ret; - } -} - static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) { /* IO was queued async, completion will happen later */