bisecting fixing commit since 69b94dd6dcd14d9bfcba35a492f5e27c15cf4d0a
building syzkaller on 340ea5301c27db4a3678f13acc430e04706a0cc6
testing commit 69b94dd6dcd14d9bfcba35a492f5e27c15cf4d0a with gcc (GCC) 8.4.1 20210217
kernel signature: e1a503f4dffa4bdfe792d99183fd14b0e18f4bb4afd1d6dcc999d51c235aac5c
all runs: crashed: divide error in fbcon_switch
testing current HEAD cf256fbcbe347b7d0ff58fe2dfa382a156bd3694
testing commit cf256fbcbe347b7d0ff58fe2dfa382a156bd3694 with gcc (GCC) 8.4.1 20210217
kernel signature: f9c7cc8e5e68a13b303a9121b2cfccb7de945b2337ec5e962aebc46d2031db03
all runs: crashed: divide error in fbcon_init
revisions tested: 2, total time: 29m59.551865544s (build: 22m56.41840636s, test: 6m28.538575321s)
the crash still happens on HEAD
commit msg: Linux 4.14.231
crash: divide error in fbcon_init
IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready
batman_adv: batadv0: Interface activated: batadv_slave_1
IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
divide error: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 7175 Comm: syz-executor.0 Not tainted 4.14.231-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8881d74b2180 task.stack: ffff8881d7650000
RIP: 0010:fbcon_init+0x6ee/0x1d50 drivers/video/fbdev/core/fbcon.c:1065
RSP: 0018:ffff8881d7657868 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8881d8208a00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 1ffff1103b0411b6 RDI: ffff8881d8208db4
RBP: ffff8881d76578f8 R08: ffffffff8a4501c0 R09: 0000000000000000
R10: ffff8881d8208d34 R11: ffff8881d8208d38 R12: ffff8881ef2d2cc0
R13: 0000000000000006 R14: ffff8881ef396d40 R15: ffff8881ef396ef8
FS:  00007fd52ee6e700(0000) GS:ffff8881f6600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000050b9b0 CR3: 00000001ee41b005 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 visual_init+0x314/0x5d0 drivers/tty/vt/vt.c:746
 vc_allocate drivers/tty/vt/vt.c:802 [inline]
 vc_allocate+0x2d3/0x700 drivers/tty/vt/vt.c:773
 vt_ioctl+0x14a0/0x2090 drivers/tty/vt/vt_ioctl.c:719
 tty_ioctl+0x438/0x1260 drivers/tty/tty_io.c:2661
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x180/0xfb0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x74/0x80 fs/ioctl.c:692
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x463b49
RSP: 002b:00007fd52ee6e188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000055bfa0 RCX: 0000000000463b49
RDX: 0000000020000000 RSI: 000000000000560f RDI: 0000000000000004
RBP: 00000000004ae538 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bfa0
R13: 00007ffd8f93290f R14: 00007fd52ee6e300 R15: 0000000000022000
Code: 89 d0 48 ba 00 00 00 00 00 fc ff df 48 8b 75 b0 48 c1 ee 03 0f b6 14 16 84 d2 74 09 80 fa 03 0f 8e 6f 10 00 00 31 d2 48 8b 7d a0 <f7> b3 b0 03 00 00 48 89 fa 48 c1 ea 03 41 89 c0 48 b8 00 00 00 
RIP: fbcon_init+0x6ee/0x1d50 drivers/video/fbdev/core/fbcon.c:1065 RSP: ffff8881d7657868
---[ end trace c0be3d448c20a29f ]---