bisecting fixing commit since 84f5ad468100f86d70096799e4ee716a17c2962f building syzkaller on ddc3e85997efdad885e208db6a98bca86e5dd52f testing commit 84f5ad468100f86d70096799e4ee716a17c2962f with gcc (GCC) 8.1.0 kernel signature: 4b36f8a1757cbeb9b671bfc43a52b3eb210da90cc19fb15450edcc599263b07e all runs: crashed: general protection fault in hsr_check_carrier_and_operstate testing current HEAD 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14 testing commit 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14 with gcc (GCC) 8.1.0 kernel signature: f155bb5792aebbe4da26e0e220b09153f8565f65dbbc4aa4353989badab560b0 all runs: crashed: general protection fault in hsr_check_carrier_and_operstate revisions tested: 2, total time: 26m49.987876043s (build: 18m40.783927754s, test: 7m7.292674592s) the crash still happens on HEAD commit msg: Linux 4.14.173 crash: general protection fault in hsr_check_carrier_and_operstate device bridge21 entered promiscuous mode device bridge16 entered promiscuous mode device macvlan0 left promiscuous mode kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN Modules linked in: CPU: 1 PID: 7707 Comm: syz-executor.0 Not tainted 4.14.173-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88809122c280 task.stack: ffff8880a06e0000 RIP: 0010:hsr_check_carrier_and_operstate+0x33/0x580 net/hsr/hsr_device.c:116 RSP: 0018:ffff8880a06e6db0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff88808f78e600 RCX: 1ffff11011ef1cd4 RDX: 0000000000000002 RSI: 0000000000000004 RDI: ffff88808f78e620 RBP: ffff8880a06e6de0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000028 R11: ffff88809122c280 R12: 0000000000000000 R13: 0000000000000004 R14: 0000000000000010 R15: ffff88808d1613c0 FS: 00007f3b3da86700(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3c8f840db8 CR3: 000000008c531000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: hsr_netdev_notify+0x535/0x9b0 net/hsr/hsr_main.c:51 notifier_call_chain+0xd6/0x150 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x11/0x20 kernel/notifier.c:401 call_netdevice_notifiers_info+0x4b/0x60 net/core/dev.c:1671 netdev_state_change+0xb5/0xe0 net/core/dev.c:1318 do_setlink+0x197f/0x2c50 net/core/rtnetlink.c:2280 rtnl_newlink+0xe0c/0x1390 net/core/rtnetlink.c:2660 rtnetlink_rcv_msg+0x34c/0x9e0 net/core/rtnetlink.c:4315 netlink_rcv_skb+0x133/0x370 net/netlink/af_netlink.c:2433 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4327 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline] netlink_unicast+0x40b/0x600 net/netlink/af_netlink.c:1313 netlink_sendmsg+0x730/0xbd0 net/netlink/af_netlink.c:1878 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0xf0 net/socket.c:656 ___sys_sendmsg+0x625/0x920 net/socket.c:2062 __sys_sendmsg+0xc1/0x140 net/socket.c:2096 SYSC_sendmsg net/socket.c:2107 [inline] SyS_sendmsg+0xd/0x20 net/socket.c:2103 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45af49 RSP: 002b:00007f3b3da85c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045af49 RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3b3da866d4 R13: 00000000004ca9a0 R14: 00000000004e3d80 R15: 00000000ffffffff Code: e5 41 57 41 56 41 55 41 54 53 48 83 ec 08 e8 25 a7 ff ff 4c 8d 70 10 49 89 c4 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 c3 04 00 00 48 b8 00 00 00 00 00 fc ff df 49 RIP: hsr_check_carrier_and_operstate+0x33/0x580 net/hsr/hsr_device.c:116 RSP: ffff8880a06e6db0 ---[ end trace 5533fc7fd8a75a7c ]---