bisecting fixing commit since fcfbdfe9626edd5bf00c732e093eed249ecdbfa1 building syzkaller on f115ae985a399ddce060f448097b8068450a8f48 testing commit fcfbdfe9626edd5bf00c732e093eed249ecdbfa1 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: b5457daf5799b0855e403ad307d1da34d7e4e9c00da6a0910e755cf174b2e1c1 all runs: crashed: BUG: unable to handle kernel paging request in vga16fb_fillrect testing current HEAD 59456c9cc40c8f75b5a7efa0fe1f211d9c6fcaf1 testing commit 59456c9cc40c8f75b5a7efa0fe1f211d9c6fcaf1 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 460add789fbc9e30ae962b5c066362183f20cdd9a028d58fb2fba56cbef25184 all runs: crashed: BUG: unable to handle kernel paging request in vga16fb_fillrect revisions tested: 2, total time: 23m58.391103873s (build: 16m57.253214742s, test: 6m26.400869744s) the crash still happens on HEAD commit msg: Linux 4.19.204 crash: BUG: unable to handle kernel paging request in vga16fb_fillrect IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50 IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready BUG: unable to handle kernel paging request at ffff888001000050 PGD c801067 P4D c801067 PUD c802067 PMD 80000000010001e1 Oops: 0003 [#1] PREEMPT SMP KASAN CPU: 0 PID: 9887 Comm: syz-executor.0 Not tainted 4.19.204-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:writeb arch/x86/include/asm/io.h:65 [inline] RIP: 0010:vga16fb_fillrect+0x87e/0x19b0 drivers/video/fbdev/vga16fb.c:923 Code: 8b 45 d0 8d 70 ff 85 c0 0f 84 30 fd ff ff 4c 63 7d c8 41 8d 7c 24 ff 31 d2 48 83 c7 01 49 8d 04 3e 45 85 e4 0f 84 0b 07 00 00 <41> 88 16 49 83 c6 01 49 39 c6 75 f4 4e 8d 34 38 83 ee 01 83 fe ff RSP: 0018:ffff88809885f1f8 EFLAGS: 00010206 RAX: ffff88800100006b RBX: 0000000000000000 RCX: 00000000000000a5 RDX: 0000000000000000 RSI: 000000000ffeb7ff RDI: 000000000000001b RBP: ffff88809885f270 R08: ffff88809885f2c4 R09: 0000000000000050 R10: 1ffff110277c4ea7 R11: ffff8880b0b6e3df R12: 000000000000001b R13: 1ffffffff132249a R14: ffff888001000050 R15: 00000000000000a5 FS: 00007fe27557e700(0000) GS:ffff8880ba200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff888001000050 CR3: 000000009931f000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bit_clear_margins+0x2ae/0x610 drivers/video/fbdev/core/bitblit.c:224 fbcon_clear_margins+0x1a8/0x320 drivers/video/fbdev/core/fbcon.c:1288 fbcon_switch+0xb24/0x16a0 drivers/video/fbdev/core/fbcon.c:2155 redraw_screen+0x319/0x830 drivers/tty/vt/vt.c:1015 fbcon_modechanged+0x515/0x770 drivers/video/fbdev/core/fbcon.c:2688 fbcon_event_notify+0x134/0x1c70 drivers/video/fbdev/core/fbcon.c:3061 notifier_call_chain+0x8a/0x160 kernel/notifier.c:93 __blocking_notifier_call_chain kernel/notifier.c:317 [inline] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] blocking_notifier_call_chain kernel/notifier.c:328 [inline] blocking_notifier_call_chain+0x6b/0xa0 kernel/notifier.c:325 fb_notifier_call_chain+0x16/0x20 drivers/video/fbdev/core/fb_notify.c:45 fb_set_var+0xb0c/0xfb0 drivers/video/fbdev/core/fbmem.c:1042 do_fb_ioctl+0x44c/0x860 drivers/video/fbdev/core/fbmem.c:1115 fb_ioctl+0xc8/0x140 drivers/video/fbdev/core/fbmem.c:1230 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4665d9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe27557e188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9 RDX: 0000000020000200 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffd93dd13ff R14: 00007fe27557e300 R15: 0000000000022000 Modules linked in: CR2: ffff888001000050 ---[ end trace 6cc9d0182f6cadb5 ]--- RIP: 0010:writeb arch/x86/include/asm/io.h:65 [inline] RIP: 0010:vga16fb_fillrect+0x87e/0x19b0 drivers/video/fbdev/vga16fb.c:923 Code: 8b 45 d0 8d 70 ff 85 c0 0f 84 30 fd ff ff 4c 63 7d c8 41 8d 7c 24 ff 31 d2 48 83 c7 01 49 8d 04 3e 45 85 e4 0f 84 0b 07 00 00 <41> 88 16 49 83 c6 01 49 39 c6 75 f4 4e 8d 34 38 83 ee 01 83 fe ff RSP: 0018:ffff88809885f1f8 EFLAGS: 00010206 RAX: ffff88800100006b RBX: 0000000000000000 RCX: 00000000000000a5 RDX: 0000000000000000 RSI: 000000000ffeb7ff RDI: 000000000000001b RBP: ffff88809885f270 R08: ffff88809885f2c4 R09: 0000000000000050 R10: 1ffff110277c4ea7 R11: ffff8880b0b6e3df R12: 000000000000001b R13: 1ffffffff132249a R14: ffff888001000050 R15: 00000000000000a5 FS: 00007fe27557e700(0000) GS:ffff8880ba200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff888001000050 CR3: 000000009931f000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 8b 45 d0 mov -0x30(%rbp),%eax 3: 8d 70 ff lea -0x1(%rax),%esi 6: 85 c0 test %eax,%eax 8: 0f 84 30 fd ff ff je 0xfffffd3e e: 4c 63 7d c8 movslq -0x38(%rbp),%r15 12: 41 8d 7c 24 ff lea -0x1(%r12),%edi 17: 31 d2 xor %edx,%edx 19: 48 83 c7 01 add $0x1,%rdi 1d: 49 8d 04 3e lea (%r14,%rdi,1),%rax 21: 45 85 e4 test %r12d,%r12d 24: 0f 84 0b 07 00 00 je 0x735 2a: 41 88 16 mov %dl,(%r14) <-- trapping instruction 2d: 49 83 c6 01 add $0x1,%r14 31: 49 39 c6 cmp %rax,%r14 34: 75 f4 jne 0x2a 36: 4e 8d 34 38 lea (%rax,%r15,1),%r14 3a: 83 ee 01 sub $0x1,%esi 3d: 83 fe ff cmp $0xffffffff,%esi