bisecting fixing commit since 2762b48e9611529239da2e68cba908dbbec9805f building syzkaller on 63631df1539816bc62c7be40779c5f3e23b23b2f testing commit 2762b48e9611529239da2e68cba908dbbec9805f with gcc (GCC) 8.4.1 20210217 kernel signature: e27ae7074ec09f3ce819c6df2c631d47a3052ca6b75dedc02fa7b6d6afba1adf all runs: crashed: general protection fault in hsr_dev_change_mtu testing current HEAD 670d6552eda8ff0c5f396d3d6f0174237917c66c testing commit 670d6552eda8ff0c5f396d3d6f0174237917c66c with gcc (GCC) 8.4.1 20210217 kernel signature: 61e2c536a666c7d93677c6236c7c640b47e2ce80046c5259c43086ff7ff7c8d1 all runs: crashed: general protection fault in hsr_dev_change_mtu revisions tested: 2, total time: 20m44.320913867s (build: 14m1.662061197s, test: 6m20.385254824s) the crash still happens on HEAD commit msg: Linux 4.14.227 crash: general protection fault in hsr_dev_change_mtu device veth0_vlan entered promiscuous mode bond0: enslaved VLAN challenged slave hsr8. Adding VLANs will be blocked as long as hsr8 is part of bond bond0 bond0: The slave device specified does not support setting the MAC address 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: 0 PID: 9687 Comm: syz-executor.1 Not tainted 4.14.227-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff888099f12300 task.stack: ffff88809b140000 RIP: 0010:hsr_dev_change_mtu+0x87/0xb0 net/hsr/hsr_device.c:149 RSP: 0018:ffff88809b146d08 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff888099192280 RCX: 1ffff110133e256f RDX: 0000000000000002 RSI: 0000000000000002 RDI: 0000000000000010 RBP: ffff88809b146d28 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000028 R11: ffff888099f12300 R12: ffff888099192d40 R13: 00000000000005dc R14: 0000000000000000 R15: ffff888099192280 FS: 00007f900b033700(0000) GS:ffff8880ba600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007effbf237000 CR3: 000000009e7ce000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __dev_set_mtu net/core/dev.c:6875 [inline] dev_set_mtu+0x1d3/0x3e0 net/core/dev.c:6910 bond_enslave+0x672/0x4b40 drivers/net/bonding/bond_main.c:1507 do_set_master net/core/rtnetlink.c:1961 [inline] do_set_master+0x163/0x1f0 net/core/rtnetlink.c:1936 do_setlink+0x93e/0x2c80 net/core/rtnetlink.c:2098 rtnl_newlink+0xeda/0x1610 net/core/rtnetlink.c:2660 rtnetlink_rcv_msg+0x34c/0x9e0 net/core/rtnetlink.c:4316 netlink_rcv_skb+0x12f/0x3b0 net/netlink/af_netlink.c:2433 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4328 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline] netlink_unicast+0x40b/0x610 net/netlink/af_netlink.c:1313 netlink_sendmsg+0x639/0xbe0 net/netlink/af_netlink.c:1878 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xac/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+0x46/0xbb RIP: 0033:0x465b09 RSP: 002b:00007f900b033188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000056c0b0 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 0000000020000600 RDI: 0000000000000005 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c0b0 R13: 00007fff565d146f R14: 00007f900b033300 R15: 0000000000022000 Code: 38 02 00 00 31 c0 5b 41 5c 41 5d 41 5e 5d c3 e8 a0 4c 71 fa eb e7 49 8d 7e 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 1c 49 8b 7e 10 ba 06 00 00 00 48 c7 c6 80 16 72 RIP: hsr_dev_change_mtu+0x87/0xb0 net/hsr/hsr_device.c:149 RSP: ffff88809b146d08 Bluetooth: hci2 command 0x0419 tx timeout ---[ end trace 8de0527c6aec8bd2 ]--- Bluetooth: hci4 command 0x0419 tx timeout