diff options
| author | Caleb Sander Mateos <csander@purestorage.com> | 2026-01-05 14:05:40 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-02-26 15:00:42 -0800 |
| commit | a0ca2ecb9260f25afed1799e9d3b142aa0eb68a2 (patch) | |
| tree | 5d18da5c015085324f41646e6292ff0531a0fa06 /io_uring | |
| parent | b520865b7ccba3fdd136a09ef2c10bb502b6667a (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 b7a077c11c21..8aa671ba4347 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -3256,7 +3256,11 @@ 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 7063ea7964e7..87b4d306cf1b 100644 --- a/io_uring/msg_ring.c +++ b/io_uring/msg_ring.c @@ -125,7 +125,11 @@ static int __io_msg_ring_data(struct io_ring_ctx *target_ctx, 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)) @@ -245,7 +249,11 @@ 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 (!msg->src_file) { int ret = io_msg_grab_file(req, issue_flags); diff --git a/io_uring/register.c b/io_uring/register.c index 3d3822ff3fd9..12318c276068 100644 --- a/io_uring/register.c +++ b/io_uring/register.c @@ -193,7 +193,8 @@ 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; |