diff options
| author | Pavel Begunkov <asml.silence@gmail.com> | 2024-06-14 01:04:29 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2024-06-13 19:25:28 -0600 |
| commit | f4a1254f2a076afb0edd473589bf40f9b4d36b41 (patch) | |
| tree | f7dad023967cad2f50d120ab55aca57cf4a59689 | |
| parent | 54559642b96116b45e4b5ca7fd9f7835b8561272 (diff) | |
| download | lwn-f4a1254f2a076afb0edd473589bf40f9b4d36b41.tar.gz lwn-f4a1254f2a076afb0edd473589bf40f9b4d36b41.zip | |
io_uring: fix cancellation overwriting req->flags
Only the current owner of a request is allowed to write into req->flags.
Hence, the cancellation path should never touch it. Add a new field
instead of the flag, move it into the 3rd cache line because it should
always be initialised. poll_refs can move further as polling is an
involved process anyway.
It's a minimal patch, in the future we can and should find a better
place for it and remove now unused REQ_F_CANCEL_SEQ.
Fixes: 521223d7c229f ("io_uring/cancel: don't default to setting req->work.cancel_seq")
Cc: stable@vger.kernel.org
Reported-by: Li Shi <sl1589472800@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6827b129f8f0ad76fa9d1f0a773de938b240ffab.1718323430.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | include/linux/io_uring_types.h | 3 | ||||
| -rw-r--r-- | io_uring/cancel.h | 4 | ||||
| -rw-r--r-- | io_uring/io_uring.c | 1 |
3 files changed, 5 insertions, 3 deletions
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index 7a6b190c7da7..b48570eaa449 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -648,7 +648,7 @@ struct io_kiocb { struct io_rsrc_node *rsrc_node; atomic_t refs; - atomic_t poll_refs; + bool cancel_seq_set; struct io_task_work io_task_work; /* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */ struct hlist_node hash_node; @@ -657,6 +657,7 @@ struct io_kiocb { /* opcode allocated if it needs to store data for async defer */ void *async_data; /* linked requests, IFF REQ_F_HARDLINK or REQ_F_LINK are set */ + atomic_t poll_refs; struct io_kiocb *link; /* custom credentials, valid IFF REQ_F_CREDS is set */ const struct cred *creds; diff --git a/io_uring/cancel.h b/io_uring/cancel.h index 76b32e65c03c..b33995e00ba9 100644 --- a/io_uring/cancel.h +++ b/io_uring/cancel.h @@ -27,10 +27,10 @@ bool io_cancel_req_match(struct io_kiocb *req, struct io_cancel_data *cd); static inline bool io_cancel_match_sequence(struct io_kiocb *req, int sequence) { - if ((req->flags & REQ_F_CANCEL_SEQ) && sequence == req->work.cancel_seq) + if (req->cancel_seq_set && sequence == req->work.cancel_seq) return true; - req->flags |= REQ_F_CANCEL_SEQ; + req->cancel_seq_set = true; req->work.cancel_seq = sequence; return false; } diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 816e93e7f949..154b25b8a613 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -2058,6 +2058,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, req->file = NULL; req->rsrc_node = NULL; req->task = current; + req->cancel_seq_set = false; if (unlikely(opcode >= IORING_OP_LAST)) { req->opcode = 0; |