From 745fb794c3e933c023af9dbb5876a5e16ad2dc71 Mon Sep 17 00:00:00 2001 From: Xuanqiang Luo Date: Wed, 8 Jul 2026 17:35:34 +0800 Subject: [PATCH] rxrpc: fix io_thread race in rxrpc_wake_up_io_thread() rxrpc_wake_up_io_thread() checks local->io_thread before waking it, but then reloads the pointer for wake_up_process(). local->io_thread is cleared with WRITE_ONCE() when the I/O thread exits, so the second load can see NULL even if the first load did not. Take a READ_ONCE() snapshot and use it for both the NULL check and the wake_up_process() call, as rxrpc_encap_rcv() already does. Fixes: 5800b1cf3fd8 ("rxrpc: Allow CHALLENGEs to the passed to the app for a RESPONSE") Signed-off-by: Xuanqiang Luo Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260708093534.53486-1-xuanqiang.luo@linux.dev Signed-off-by: Paolo Abeni --- net/rxrpc/ar-internal.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index ce946b0a03e2..865f05fe37ab 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -1285,9 +1285,11 @@ int rxrpc_io_thread(void *data); void rxrpc_post_response(struct rxrpc_connection *conn, struct sk_buff *skb); static inline void rxrpc_wake_up_io_thread(struct rxrpc_local *local) { - if (!local->io_thread) + struct task_struct *io_thread = READ_ONCE(local->io_thread); + + if (!io_thread) return; - wake_up_process(READ_ONCE(local->io_thread)); + wake_up_process(io_thread); } static inline bool rxrpc_protocol_error(struct sk_buff *skb, enum rxrpc_abort_reason why)