diff options
| author | Caleb Sander Mateos <csander@purestorage.com> | 2026-01-05 14:05:40 -0700 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2026-03-04 07:19:27 -0500 |
| commit | a67a23e9dedffb6b77335dc12d03d4a39a66024a (patch) | |
| tree | 6770418b94587837b783a4a8a066adeeb8410216 /io_uring | |
| parent | becedc3aceca9e4c155b2c7f8df741ab4896fd56 (diff) | |
io_uring: use release-acquire ordering for IORING_SETUP_R_DISABLED
[ Upstream commit 7a8737e1132ff07ca225aa7a4008f87319b5b1ca ]
io_uring_enter(), __io_msg_ring_data(), and io_msg_send_fd() read
ctx->flags and ctx->submitter_task without holding the ctx's uring_lock.
This means they may race with the assignment to ctx->submitter_task and
the clearing of IORING_SETUP_R_DISABLED from ctx->flags in
io_register_enable_rings(). Ensure the correct ordering of the
ctx->flags and ctx->submitter_task memory accesses by storing to
ctx->flags using release ordering and loading it using acquire ordering.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Fixes: 4add705e4eeb ("io_uring: remove io_register_submitter")
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io_uring.c | 6 | ||||
| -rw-r--r-- | io_uring/msg_ring.c | 12 | ||||
| -rw-r--r-- | io_uring/register.c | 3 |
3 files changed, 17 insertions, 4 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 99b0b1ba0fe2..5c60442e6702 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -3312,7 +3312,11 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, ctx = file->private_data; ret = -EBADFD; - if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED)) + /* + * Keep IORING_SETUP_R_DISABLED check before submitter_task load + * in io_uring_add_tctx_node() -> __io_uring_add_tctx_node_from_submit() + */ + if (unlikely(smp_load_acquire(&ctx->flags) & IORING_SETUP_R_DISABLED)) goto out; /* diff --git a/io_uring/msg_ring.c b/io_uring/msg_ring.c index 97708e5132bc..3cf59d8c5807 100644 --- a/io_uring/msg_ring.c +++ b/io_uring/msg_ring.c @@ -126,7 +126,11 @@ static int io_msg_ring_data(struct io_kiocb *req, unsigned int issue_flags) return -EINVAL; if (!(msg->flags & IORING_MSG_RING_FLAGS_PASS) && msg->dst_fd) return -EINVAL; - if (target_ctx->flags & IORING_SETUP_R_DISABLED) + /* + * Keep IORING_SETUP_R_DISABLED check before submitter_task load + * in io_msg_data_remote() -> io_msg_remote_post() + */ + if (smp_load_acquire(&target_ctx->flags) & IORING_SETUP_R_DISABLED) return -EBADFD; if (io_msg_need_remote(target_ctx)) @@ -237,7 +241,11 @@ static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags) return -EINVAL; if (target_ctx == ctx) return -EINVAL; - if (target_ctx->flags & IORING_SETUP_R_DISABLED) + /* + * Keep IORING_SETUP_R_DISABLED check before submitter_task load + * in io_msg_fd_remote() + */ + if (smp_load_acquire(&target_ctx->flags) & IORING_SETUP_R_DISABLED) return -EBADFD; if (!src_file) { src_file = io_msg_grab_file(req, issue_flags); diff --git a/io_uring/register.c b/io_uring/register.c index a325b493ae12..f700ddf1f1d1 100644 --- a/io_uring/register.c +++ b/io_uring/register.c @@ -190,7 +190,8 @@ static int io_register_enable_rings(struct io_ring_ctx *ctx) if (ctx->restrictions.registered) ctx->restricted = 1; - ctx->flags &= ~IORING_SETUP_R_DISABLED; + /* Keep submitter_task store before clearing IORING_SETUP_R_DISABLED */ + smp_store_release(&ctx->flags, ctx->flags & ~IORING_SETUP_R_DISABLED); if (ctx->sq_data && wq_has_sleeper(&ctx->sq_data->wait)) wake_up(&ctx->sq_data->wait); return 0; |