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authorJens Axboe <axboe@kernel.dk>2026-03-09 14:35:49 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2026-03-19 16:08:51 +0100
commitb0d0903594dd68bb9156236955019acb49ca51a4 (patch)
tree4151b239eaa764cad1a3856a01c8011373356504
parent7cc4530b3e952d4a5947e1e55d06620d8845d4f5 (diff)
io_uring/eventfd: use ctx->rings_rcu for flags checking
Commit 177c69432161f6e4bab07ccacf8a1748a6898a6b upstream. Similarly to what commit e78f7b70e837 did for local task work additions, use ->rings_rcu under RCU rather than dereference ->rings directly. See that commit for more details. Cc: stable@vger.kernel.org Fixes: 79cfe9e59c2a ("io_uring/register: add IORING_REGISTER_RESIZE_RINGS") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--io_uring/eventfd.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/io_uring/eventfd.c b/io_uring/eventfd.c
index 78f8ab7db104..ab789e1ebe91 100644
--- a/io_uring/eventfd.c
+++ b/io_uring/eventfd.c
@@ -76,11 +76,15 @@ void io_eventfd_signal(struct io_ring_ctx *ctx, bool cqe_event)
{
bool skip = false;
struct io_ev_fd *ev_fd;
-
- if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
- return;
+ struct io_rings *rings;
guard(rcu)();
+
+ rings = rcu_dereference(ctx->rings_rcu);
+ if (!rings)
+ return;
+ if (READ_ONCE(rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
+ return;
ev_fd = rcu_dereference(ctx->io_ev_fd);
/*
* Check again if ev_fd exists in case an io_eventfd_unregister call