Hi Li,

On 30/03/2026 14:03, Li Xiasong wrote:

syzbot reported a soft lockup in mptcp_recvmsg() [0].

When receiving data with MSG_PEEK | MSG_WAITALL flags, the skb is not
removed from the sk_receive_queue. This causes sk_wait_data() to always
find available data and never perform actual waiting, leading to a soft
lockup.

Fix this by adding a 'last' parameter to track the last peeked skb.
This allows sk_wait_data() to make informed waiting decisions and prevent
infinite loops when MSG_PEEK is used.

Thank you for this new version:

Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

@netdev maintainers: this patch can be applied in 'net' directly, thank you!

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.