diff options
| author | Jens Axboe <axboe@kernel.dk> | 2026-05-15 10:19:09 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-05-15 11:02:16 -0600 |
| commit | ccd25890f73c082fe2657ed227b497d6ac5fdc40 (patch) | |
| tree | 74848dee416e5d2fcff71f901b36131141834269 | |
| parent | f44d38a31f1802b7222adaea9ee69f9d280f698a (diff) | |
io_uring/net: punt IORING_OP_BIND async if it needs file create
For two reasons:
1) An opcode cannot block inside io_uring_enter() doing submissions, as
it'll stall the submission side pipeline.
2) Ending up in sb_start_write() -> __sb_start_write() ->
percpu_down_read_freezable() introduces a new lockdep edge, which it
correctly complains about.
Check if the socket type is AF_UNIX and has a non-empty pathname. If it
does, mark it REQ_F_FORCE_ASYNC to punt the submission to io-wq rather
than attempt to do it inline.
Fixes: 7481fd93fa0a ("io_uring: Introduce IORING_OP_BIND")
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | io_uring/net.c | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/io_uring/net.c b/io_uring/net.c index 30cd22c0b934..8df15b639358 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -4,6 +4,7 @@ #include <linux/file.h> #include <linux/slab.h> #include <linux/net.h> +#include <linux/un.h> #include <linux/compat.h> #include <net/compat.h> #include <linux/io_uring.h> @@ -1799,11 +1800,29 @@ out: return IOU_COMPLETE; } +/* + * Check if bind request would potentially end up with filename_create(), + * which in turn end up in mnt_want_write() which will grab the fs + * percpu start write sem. This can trigger a lockdep warning. + */ +static int io_bind_file_create(const struct io_async_msghdr *io, int addr_len) +{ + const struct sockaddr_un *sun; + + if (io->addr.ss_family != AF_UNIX) + return 0; + if (addr_len <= offsetof(struct sockaddr_un, sun_path)) + return 0; + sun = (const struct sockaddr_un *) &io->addr; + return sun->sun_path[0] != '\0'; +} + int io_bind_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_bind *bind = io_kiocb_to_cmd(req, struct io_bind); struct sockaddr __user *uaddr; struct io_async_msghdr *io; + int ret; if (sqe->len || sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in) return -EINVAL; @@ -1814,7 +1833,12 @@ int io_bind_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) io = io_msg_alloc_async(req); if (unlikely(!io)) return -ENOMEM; - return move_addr_to_kernel(uaddr, bind->addr_len, &io->addr); + ret = move_addr_to_kernel(uaddr, bind->addr_len, &io->addr); + if (unlikely(ret)) + return ret; + if (io_bind_file_create(io, bind->addr_len)) + req->flags |= REQ_F_FORCE_ASYNC; + return 0; } int io_bind(struct io_kiocb *req, unsigned int issue_flags) |