Hello, When using Syzkaller to fuzz the latest Linux kernel, the following crash was triggered. HEAD commit: a7904a538933 Linux 5.16-rc6 git tree: upstream console output: https://paste.ubuntu.com/p/Rvt9f7wByG/plain/ kernel config: https://paste.ubuntu.com/p/FDDNHDxtwz/plain/ C reproducer: https://paste.ubuntu.com/p/KzH8Wx9H9R/plain/ Syzlang reproducer: https://paste.ubuntu.com/p/cDfk6NK4S4/plain/ If you fix this issue, please add the following tag to the commit: Reported-by: Yiru Xu <xyru1999@xxxxxxxxx> BUG: unable to handle page fault for address: fffff520009cf200 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 13ffed067 P4D 13ffed067 PUD 10dba067 PMD 18fd2067 PTE 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 19972 Comm: syz-executor.5 Not tainted 5.16.0-rc6 #9 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline] RIP: 0010:sys_imageblit+0x650/0x13f0 drivers/video/fbdev/core/sysimgblt.c:275 Code: 03 38 d0 7c 08 84 d2 0f 85 44 0d 00 00 48 bf 00 00 00 00 00 fc ff df 8b 44 24 30 23 03 8b 5c 24 20 31 c3 4c 89 f0 48 c1 e8 03 <0f> b6 14 38 4c 89 f0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 01 RSP: 0018:ffffc9000324f330 EFLAGS: 00010216 RAX: 1ffff920009cf200 RBX: 0000000000000000 RCX: 0000000000000007 RDX: 0000000000000000 RSI: dffffc0000000000 RDI: dffffc0000000000 RBP: ffff8880198c4000 R08: ffffffff841fac07 R09: 000000000000001f R10: 0000000000000005 R11: fffffbfff1b20a42 R12: 0000000000000007 R13: 000000000000094b R14: ffffc90004e79000 R15: ffffc90004e79004 FS: 00007f59ce6a3700(0000) GS:ffff888135c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffff520009cf200 CR3: 000000010d39f000 CR4: 0000000000350ee0 Call Trace: <TASK> drm_fb_helper_sys_imageblit+0x1c/0x180 drivers/gpu/drm/drm_fb_helper.c:794 drm_fbdev_fb_imageblit+0x179/0x260 drivers/gpu/drm/drm_fb_helper.c:2288 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:124 [inline] bit_putcs+0x8ed/0xd80 drivers/video/fbdev/core/bitblit.c:173 fbcon_putcs+0x367/0x450 drivers/video/fbdev/core/fbcon.c:1277 do_update_region+0x399/0x630 drivers/tty/vt/vt.c:676 invert_screen+0x2a7/0x610 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+0xda8/0x10a0 drivers/tty/vt/vt.c:1257 fbcon_do_set_font+0x472/0x770 drivers/video/fbdev/core/fbcon.c:1928 fbcon_set_font+0x80f/0xa00 drivers/video/fbdev/core/fbcon.c:2014 con_font_set drivers/tty/vt/vt.c:4666 [inline] con_font_op+0x73a/0xca0 drivers/tty/vt/vt.c:4710 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline] vt_ioctl+0x1de9/0x2af0 drivers/tty/vt/vt_ioctl.c:752 tty_ioctl+0xc80/0x1450 drivers/tty/tty_io.c:2805 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: 0033:0x7f59cfd3189d Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 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:00007f59ce6a2c28 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f59cfe50f60 RCX: 00007f59cfd3189d RDX: 0000000020000080 RSI: 0000000000004b72 RDI: 0000000000000005 RBP: 00007f59cfd9e00d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd4f88b4ff R14: 00007f59cfe50f60 R15: 00007f59ce6a2dc0 </TASK> Modules linked in: CR2: fffff520009cf200 ---[ end trace 4fd686b04a4d7413 ]--- RIP: 0010:fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline] RIP: 0010:sys_imageblit+0x650/0x13f0 drivers/video/fbdev/core/sysimgblt.c:275 Code: 03 38 d0 7c 08 84 d2 0f 85 44 0d 00 00 48 bf 00 00 00 00 00 fc ff df 8b 44 24 30 23 03 8b 5c 24 20 31 c3 4c 89 f0 48 c1 e8 03 <0f> b6 14 38 4c 89 f0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 01 RSP: 0018:ffffc9000324f330 EFLAGS: 00010216 RAX: 1ffff920009cf200 RBX: 0000000000000000 RCX: 0000000000000007 RDX: 0000000000000000 RSI: dffffc0000000000 RDI: dffffc0000000000 RBP: ffff8880198c4000 R08: ffffffff841fac07 R09: 000000000000001f R10: 0000000000000005 R11: fffffbfff1b20a42 R12: 0000000000000007 R13: 000000000000094b R14: ffffc90004e79000 R15: ffffc90004e79004 FS: 00007f59ce6a3700(0000) GS:ffff888135c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffff520009cf200 CR3: 000000010d39f000 CR4: 0000000000350ee0 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 38 d0 cmp %dl,%al 2: 7c 08 jl 0xc 4: 84 d2 test %dl,%dl 6: 0f 85 44 0d 00 00 jne 0xd50 c: 48 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%rdi 13: fc ff df 16: 8b 44 24 30 mov 0x30(%rsp),%eax 1a: 23 03 and (%rbx),%eax 1c: 8b 5c 24 20 mov 0x20(%rsp),%ebx 20: 31 c3 xor %eax,%ebx 22: 4c 89 f0 mov %r14,%rax 25: 48 c1 e8 03 shr $0x3,%rax * 29: 0f b6 14 38 movzbl (%rax,%rdi,1),%edx <-- trapping instruction 2d: 4c 89 f0 mov %r14,%rax 30: 83 e0 07 and $0x7,%eax 33: 83 c0 03 add $0x3,%eax 36: 38 d0 cmp %dl,%al 38: 7c 08 jl 0x42 3a: 84 d2 test %dl,%dl 3c: 0f .byte 0xf 3d: 85 01 test %eax,(%rcx) Best Regards, Yiru
