Hello, syzbot found the following issue on: HEAD commit: 3dbdb38e Merge branch 'for-5.14' of git://git.kernel.org/p.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1323c402300000 kernel config: https://syzkaller.appspot.com/x/.config?x=a1fcf15a09815757 dashboard link: https://syzkaller.appspot.com/bug?extid=04168c8063cfdde1db5e syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11f0e772300000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1114b9b0300000 Bisection is inconclusive: the issue happens on the oldest tested release. bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10fa45d8300000 final oops: https://syzkaller.appspot.com/x/report.txt?x=12fa45d8300000 console output: https://syzkaller.appspot.com/x/log.txt?x=14fa45d8300000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+04168c8063cfdde1db5e@xxxxxxxxxxxxxxxxxxxxxxxxx BUG: unable to handle page fault for address: ffff888001000050 #PF: supervisor write access in kernel mode #PF: error_code(0x0003) - permissions violation PGD 10e01067 P4D 10e01067 PUD 10e02067 PMD 80000000010001e1 Oops: 0003 [#1] PREEMPT SMP KASAN CPU: 1 PID: 8433 Comm: syz-executor067 Tainted: G W 5.13.0-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+0x993/0x18d0 drivers/video/fbdev/vga16fb.c:923 Code: 6c fd 48 63 44 24 10 45 31 f6 48 89 04 24 e8 44 a6 6c fd 31 ff 89 de 31 ed e8 79 ad 6c fd 85 db 4d 89 ec 74 22 e8 2d a6 6c fd <45> 88 34 24 83 c5 01 89 df 49 83 c4 01 89 ee e8 49 ae 6c fd 39 eb RSP: 0018:ffffc90000eff848 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 000000000000001b RCX: 0000000000000000 RDX: ffff88802d949c40 RSI: ffffffff8408e403 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8408dd8d R10: ffffffff8408e3f7 R11: 0000000000000000 R12: ffff888001000050 R13: ffff888001000050 R14: 0000000000000000 R15: 000000000ffeb7ff FS: 0000000001aa2300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff888001000050 CR3: 00000000346fb000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bit_clear_margins+0x3f6/0x4b0 drivers/video/fbdev/core/bitblit.c:224 fbcon_clear_margins+0x1f1/0x280 drivers/video/fbdev/core/fbcon.c:1315 fbcon_switch+0xa8c/0x1620 drivers/video/fbdev/core/fbcon.c:2146 redraw_screen+0x2b9/0x740 drivers/tty/vt/vt.c:1021 fbcon_modechanged+0x593/0x6d0 drivers/video/fbdev/core/fbcon.c:2651 fbcon_update_vcs+0x3a/0x50 drivers/video/fbdev/core/fbcon.c:2696 do_fb_ioctl+0x62e/0x690 drivers/video/fbdev/core/fbmem.c:1110 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl fs/ioctl.c:1055 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x43efd9 Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc362df848 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043efd9 RDX: 0000000020000200 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 0000000000402fc0 R08: 0000000000000000 R09: 0000000000400488 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000403050 R13: 0000000000000000 R14: 00000000004ac018 R15: 0000000000400488 Modules linked in: CR2: ffff888001000050 ---[ end trace 39dce64bc5621bd3 ]--- RIP: 0010:writeb arch/x86/include/asm/io.h:65 [inline] RIP: 0010:vga16fb_fillrect+0x993/0x18d0 drivers/video/fbdev/vga16fb.c:923 Code: 6c fd 48 63 44 24 10 45 31 f6 48 89 04 24 e8 44 a6 6c fd 31 ff 89 de 31 ed e8 79 ad 6c fd 85 db 4d 89 ec 74 22 e8 2d a6 6c fd <45> 88 34 24 83 c5 01 89 df 49 83 c4 01 89 ee e8 49 ae 6c fd 39 eb RSP: 0018:ffffc90000eff848 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 000000000000001b RCX: 0000000000000000 RDX: ffff88802d949c40 RSI: ffffffff8408e403 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8408dd8d R10: ffffffff8408e3f7 R11: 0000000000000000 R12: ffff888001000050 R13: ffff888001000050 R14: 0000000000000000 R15: 000000000ffeb7ff FS: 0000000001aa2300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff888001000050 CR3: 00000000346fb000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches