During Syzkaller reproducer testing on 5.4.y (5.4.121-rc1) the following warning occurred:

general protection fault in tcf_generic_walker https://syzkaller.appspot.com//bug?id=a85a4c2d373f7f8ff9ac5ee351e60d3c042cc7...

This missing upstream commit is needed to fix the crash in 5.4.y: 580e4273d7a883ececfefa692c1f96bdbacb99b5 net_sched: check error pointer in tcf_dump_walker()

debugfs: Directory 'sg0' with parent 'block' already present! blktrace: debugfs_dir not present for sg0 so skipping kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP KASAN NOPTI CPU: 0 PID: 16603 Comm: syz-executor.7 Not tainted 5.4.135-rc1-syzk #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 RIP: 0010:tcf_dump_walker net/sched/act_api.c:236 [inline] RIP: 0010:tcf_generic_walker+0x3ac/0xbd0 net/sched/act_api.c:340 Code: 31 ff 48 89 de e8 e4 92 b9 f5 48 85 db 74 44 e8 aa 91 b9 f5 49 8d 7c 24 30 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 06 07 00 00 49 8b 5c 24 30 48 2b 9d 18 ff ff ff RSP: 0018:ffff888048f37240 EFLAGS: 00010212 RAX: 0000000000000004 RBX: 0000000100261497 RCX: dffffc0000000000 RDX: 00000000000006e0 RSI: ffffffff8bbbbc06 RDI: 0000000000000020 RBP: ffff888048f37388 R08: ffff888046e61740 R09: ffffed10091e6e3c R10: ffffed10091e6e3b R11: ffff888048f371df R12: fffffffffffffff0 R13: 00000000ffffffff R14: 0000000000000000 R15: ffff8880665488c0 FS: 00007fdde8ed0700(0000) GS:ffff88810b200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2fb21000 CR3: 0000000050326000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000600 Call Trace: tunnel_key_walker+0x91/0xe0 net/sched/act_tunnel_key.c:577 tc_dump_action+0x748/0xf50 net/sched/act_api.c:1524 netlink_dump+0x53b/0xe80 net/netlink/af_netlink.c:2247 __netlink_dump_start+0x5a2/0x7d0 net/netlink/af_netlink.c:2355 netlink_dump_start include/linux/netlink.h:233 [inline] rtnetlink_rcv_msg+0x707/0xb00 net/core/rtnetlink.c:5222 netlink_rcv_skb+0x178/0x490 net/netlink/af_netlink.c:2480 rtnetlink_rcv+0x21/0x30 net/core/rtnetlink.c:5277 netlink_unicast_kernel net/netlink/af_netlink.c:1305 [inline] netlink_unicast+0x561/0x710 net/netlink/af_netlink.c:1331 netlink_sendmsg+0x8c9/0xda0 net/netlink/af_netlink.c:1920 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0x155/0x190 net/socket.c:657 ____sys_sendmsg+0x738/0x8c0 net/socket.c:2284 ___sys_sendmsg+0x10f/0x190 net/socket.c:2338 __sys_sendmsg+0x115/0x1f0 net/socket.c:2384 __do_sys_sendmsg net/socket.c:2393 [inline] __se_sys_sendmsg net/socket.c:2391 [inline] __x64_sys_sendmsg+0x7d/0xc0 net/socket.c:2391 do_syscall_64+0xe6/0x4d0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x4595f9 Code: fc ff 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 0b 42 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fdde8ecfc48 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000002e680 RCX: 00000000004595f9 RDX: 0000000000000000 RSI: 0000000020000200 RDI: 0000000000000004 RBP: 000000000077bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000077bf0c R13: 0000000000021000 R14: 000000000077bf00 R15: 00007fdde8ed0700 Modules linked in:

Cong Wang (1): net_sched: check error pointer in tcf_dump_walker()

net/sched/act_api.c | 2 ++ 1 file changed, 2 insertions(+)