On Tue, Mar 12, 2019 at 10:42:50AM -0700, Zubin Mithra wrote:

Hello,

Syzkaller has triggered a GPF when fuzzing a 4.4 kernel with the following calltrace.

Call Trace: [<ffffffff8225c7cb>] sk_backlog_rcv include/net/sock.h:874 [inline] [<ffffffff8225c7cb>] __release_sock net/core/sock.c:2059 [inline] [<ffffffff8225c7cb>] release_sock+0x16b/0x520 net/core/sock.c:2507 [<ffffffff826d171b>] udp_sendmsg+0x115b/0x1c70 net/ipv4/udp.c:1107 [<ffffffff82700efc>] inet_sendmsg+0x20c/0x4d0 net/ipv4/af_inet.c:780 [<ffffffff8224b7f1>] sock_sendmsg_nosec net/socket.c:638 [inline] [<ffffffff8224b7f1>] sock_sendmsg+0xd1/0x110 net/socket.c:648 [<ffffffff8224c4bc>] SYSC_sendto+0x21c/0x370 net/socket.c:1678 [<ffffffff82251635>] SyS_sendto+0x45/0x60 net/socket.c:1646 [<ffffffff82a62a67>] entry_SYSCALL_64_fastpath+0x1e/0xa0 Code: 74 24 58 41 f6 c6 01 0f 85 b2 08 00 00 e8 65 d2 c3 fe 49 83 e6 fe 48 b8 00 00 00 00 00 fc ff df 49 8d 7e 60 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 01 0f 8e b9 0e 00 00 41 f6 46 60 04 RIP [<ffffffff826d3014>] __xfrm_policy_check2 include/net/xfrm.h:1070 [inline] RIP [<ffffffff826d3014>] xfrm_policy_check include/net/xfrm.h:1076 [inline] RIP [<ffffffff826d3014>] xfrm4_policy_check include/net/xfrm.h:1081 [inline] RIP [<ffffffff826d3014>] udp_queue_rcv_skb+0x194/0x1590 net/ipv4/udp.c:1520 RSP <ffff8800b987f930>

Could the following patch be applied to v4.4.y? It is present in v4.9.y.

• 30c7be26fd35 ("udplite: call proper backlog handlers")

Tests run:

• Chrome OS tryjob tests
• Syzkaller reproducer

Now queued up, thanks.

greg k-h