In tipc_recvmsg(), the copy length is computed as: copy = min_t(int, dlen - offset, buflen); buflen is size_t but min_t(int, ...) casts it to int. When buflen exceeds INT_MAX (e.g. 0xFFFFFFFF via io_uring provided buffers), it wraps negative, wins the comparison, and the negative copy length propagates to simple_copy_to_iter() where int-to-size_t promotion makes it SIZE_MAX, triggering a WARN_ON. tipc_recvstream() has the same pattern. Kernel panic - not syncing: kernel: panic_on_warn set ... RIP: 0010:simple_copy_to_iter+0x9e/0xd0 (net/core/datagram.c:521) Call Trace: __skb_datagram_iter+0x123/0x8b0 (net/core/datagram.c:402) skb_copy_datagram_iter+0x77/0x1a0 (net/core/datagram.c:534) tipc_recvmsg+0x3d7/0xe80 (net/tipc/socket.c:1934) io_recvmsg+0x47e/0xda0 Fix by changing min_t(int, ...) to min_t(size_t, ...) in both functions. The result is always <= (dlen - offset), which is bounded by TIPC maximum message size (0x1ffff bytes), so the implicit narrowing on assignment to int copy is always safe. Fixes: e9f8b10101c6 ("tipc: refactor function tipc_sk_recvmsg()") Fixes: ec8a09fbbeff ("tipc: refactor function tipc_sk_recv_stream()") Reported-by: AutonomousCodeSecurity@microsoft.com Signed-off-by: Cen Zhang (Microsoft) --- net/tipc/socket.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/tipc/socket.c b/net/tipc/socket.c index e564341e0216..ff858727344e 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -1935,7 +1935,7 @@ static int tipc_recvmsg(struct socket *sock, struct msghdr *m, if (likely(!err)) { int offset = skb_cb->bytes_read; - copy = min_t(int, dlen - offset, buflen); + copy = min_t(size_t, dlen - offset, buflen); rc = skb_copy_datagram_msg(skb, hlen + offset, m, copy); if (unlikely(rc)) goto exit; @@ -2067,7 +2067,7 @@ static int tipc_recvstream(struct socket *sock, struct msghdr *m, /* Copy data if msg ok, otherwise return error/partial data */ if (likely(!err)) { offset = skb_cb->bytes_read; - copy = min_t(int, dlen - offset, buflen - copied); + copy = min_t(size_t, dlen - offset, buflen - copied); rc = skb_copy_datagram_msg(skb, hlen + offset, m, copy); if (unlikely(rc)) break; -- 2.53.0