syzbot has found a reproducer for the following issue on: HEAD commit: 7fc5253f5a13 Add linux-next specific files for 20220120 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=16385270700000 kernel config: https://syzkaller.appspot.com/x/.config?x=94e8da4df9ab6319 dashboard link: https://syzkaller.appspot.com/bug?extid=14b0e8f3fd1612e35350 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=155dde3db00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=125298e0700000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+14b0e8f3fd1612e35350@xxxxxxxxxxxxxxxxxxxxxxxxx BUG: unable to handle page fault for address: fffff520008b2208 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 23ffed067 P4D 23ffed067 PUD 10db4067 PMD 1470c4067 PTE 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 3595 Comm: syz-executor362 Not tainted 5.16.0-next-20220120-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline] RIP: 0010:sys_imageblit+0x656/0x1430 drivers/video/fbdev/core/sysimgblt.c:275 Code: 14 38 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 b6 0c 00 00 8b 44 24 20 23 03 8b 5c 24 18 31 c3 48 89 e8 48 c1 e8 03 <42> 0f b6 14 38 48 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 RSP: 0018:ffffc90002a1f368 EFLAGS: 00010a02 RAX: 1ffff920008b2208 RBX: 0000000000000000 RCX: 0000000000000007 RDX: 0000000000000000 RSI: ffffffff84257bf0 RDI: 0000000000000003 RBP: ffffc90004591040 R08: 000000000000001f R09: ffffffff84257a74 R10: ffffffff84257be1 R11: 0000000000000020 R12: 0000000000000007 R13: 00000000000003ef R14: ffff888146efc7e0 R15: dffffc0000000000 FS: 0000555555c5d300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffff520008b2208 CR3: 0000000023b12000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> drm_fb_helper_sys_imageblit drivers/gpu/drm/drm_fb_helper.c:794 [inline] drm_fbdev_fb_imageblit+0x15c/0x350 drivers/gpu/drm/drm_fb_helper.c:2288 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:124 [inline] bit_putcs+0x6e1/0xd20 drivers/video/fbdev/core/bitblit.c:173 fbcon_putcs+0x353/0x440 drivers/video/fbdev/core/fbcon.c:1277 do_update_region+0x399/0x630 drivers/tty/vt/vt.c:676 invert_screen+0x1d4/0x600 drivers/tty/vt/vt.c:800 highlight drivers/tty/vt/selection.c:57 [inline] clear_selection drivers/tty/vt/selection.c:84 [inline] clear_selection+0x55/0x70 drivers/tty/vt/selection.c:80 vc_do_resize+0xe6e/0x1180 drivers/tty/vt/vt.c:1257 fbcon_do_set_font+0x47a/0x760 drivers/video/fbdev/core/fbcon.c:1928 fbcon_set_font+0x817/0xa00 drivers/video/fbdev/core/fbcon.c:2014 con_font_set drivers/tty/vt/vt.c:4666 [inline] con_font_op+0x73a/0xc90 drivers/tty/vt/vt.c:4710 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline] vt_ioctl+0x1e26/0x2b10 drivers/tty/vt/vt_ioctl.c:752 tty_ioctl+0xbbd/0x1660 drivers/tty/tty_io.c:2778 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 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: 0033:0x7f3bac0e1349 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:00007ffff160a718 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3bac0e1349 RDX: 0000000020000000 RSI: 0000000000004b72 RDI: 0000000000000004 RBP: 00007f3bac0a51d0 R08: 000000000000000d R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3bac0a5260 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> Modules linked in: CR2: fffff520008b2208 ---[ end trace 0000000000000000 ]--- RIP: 0010:fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline] RIP: 0010:sys_imageblit+0x656/0x1430 drivers/video/fbdev/core/sysimgblt.c:275 Code: 14 38 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 b6 0c 00 00 8b 44 24 20 23 03 8b 5c 24 18 31 c3 48 89 e8 48 c1 e8 03 <42> 0f b6 14 38 48 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 RSP: 0018:ffffc90002a1f368 EFLAGS: 00010a02 RAX: 1ffff920008b2208 RBX: 0000000000000000 RCX: 0000000000000007 RDX: 0000000000000000 RSI: ffffffff84257bf0 RDI: 0000000000000003 RBP: ffffc90004591040 R08: 000000000000001f R09: ffffffff84257a74 R10: ffffffff84257be1 R11: 0000000000000020 R12: 0000000000000007 R13: 00000000000003ef R14: ffff888146efc7e0 R15: dffffc0000000000 FS: 0000555555c5d300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffff520008b2208 CR3: 0000000023b12000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 14 38 adc $0x38,%al 2: 48 89 d8 mov %rbx,%rax 5: 83 e0 07 and $0x7,%eax 8: 83 c0 03 add $0x3,%eax b: 38 d0 cmp %dl,%al d: 7c 08 jl 0x17 f: 84 d2 test %dl,%dl 11: 0f 85 b6 0c 00 00 jne 0xccd 17: 8b 44 24 20 mov 0x20(%rsp),%eax 1b: 23 03 and (%rbx),%eax 1d: 8b 5c 24 18 mov 0x18(%rsp),%ebx 21: 31 c3 xor %eax,%ebx 23: 48 89 e8 mov %rbp,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 0f b6 14 38 movzbl (%rax,%r15,1),%edx <-- trapping instruction 2f: 48 89 e8 mov %rbp,%rax 32: 83 e0 07 and $0x7,%eax 35: 83 c0 03 add $0x3,%eax 38: 38 d0 cmp %dl,%al 3a: 7c 08 jl 0x44 3c: 84 d2 test %dl,%dl 3e: 0f .byte 0xf 3f: 85 .byte 0x85
