Re: [syzbot] BUG: unable to handle kernel paging request in vga16fb_fillrect

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syzbot

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Jul 26, 2021, 5:13:13 AM7/26/21
to chouhan.sh...@gmail.com, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: unable to handle kernel paging request in vga16fb_fillrect

BUG: unable to handle page fault for address: ffff888001000050
#PF: supervisor write access in kernel mode
#PF: error_code(0x0003) - permissions violation
PGD 10601067 P4D 10601067 PUD 10602067 PMD 80000000010001e1
Oops: 0003 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 10185 Comm: syz-executor.5 Not tainted 5.14.0-rc3-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: 68 fd 48 63 44 24 10 45 31 f6 48 89 04 24 e8 94 90 68 fd 31 ff 89 de 31 ed e8 c9 97 68 fd 85 db 4d 89 ec 74 22 e8 7d 90 68 fd <45> 88 34 24 83 c5 01 89 df 49 83 c4 01 89 ee e8 99 98 68 fd 39 eb
RSP: 0018:ffffc9000b5bf848 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 000000000000001b RCX: 0000000000000000
RDX: ffff888014388000 RSI: ffffffff840cfa73 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff840cf3fd
R10: ffffffff840cfa67 R11: 0000000000000000 R12: ffff888001000050
R13: ffff888001000050 R14: 0000000000000000 R15: 000000000ffeb7ff
FS: 00007f5c9b12d700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff888001000050 CR3: 000000003735f000 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:1108
fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1183
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: 0033:0x4665d9
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:00007f5c9b12d188 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: 00007ffd433be39f R14: 00007f5c9b12d300 R15: 0000000000022000
Modules linked in:
CR2: ffff888001000050
---[ end trace 8435df08be306de0 ]---
RIP: 0010:writeb arch/x86/include/asm/io.h:65 [inline]
RIP: 0010:vga16fb_fillrect+0x993/0x18d0 drivers/video/fbdev/vga16fb.c:923
Code: 68 fd 48 63 44 24 10 45 31 f6 48 89 04 24 e8 94 90 68 fd 31 ff 89 de 31 ed e8 c9 97 68 fd 85 db 4d 89 ec 74 22 e8 7d 90 68 fd <45> 88 34 24 83 c5 01 89 df 49 83 c4 01 89 ee e8 99 98 68 fd 39 eb
RSP: 0018:ffffc9000b5bf848 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 000000000000001b RCX: 0000000000000000
RDX: ffff888014388000 RSI: ffffffff840cfa73 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff840cf3fd
R10: ffffffff840cfa67 R11: 0000000000000000 R12: ffff888001000050
R13: ffff888001000050 R14: 0000000000000000 R15: 000000000ffeb7ff
FS: 00007f5c9b12d700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff888001000050 CR3: 000000003735f000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


Tested on:

commit: ff117646 Linux 5.14-rc3
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16b28bcc300000
kernel config: https://syzkaller.appspot.com/x/.config?x=a9e88c90e7151783
dashboard link: https://syzkaller.appspot.com/bug?extid=04168c8063cfdde1db5e
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1

syzbot

unread,
Jul 30, 2021, 11:08:08 AM7/30/21
to chouhan.sh...@gmail.com, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: unable to handle kernel paging request in vga16fb_fillrect

BUG: unable to handle page fault for address: ffff888001000050
#PF: supervisor write access in kernel mode
#PF: error_code(0x0003) - permissions violation
PGD 10601067 P4D 10601067 PUD 10602067 PMD 80000000010001e1
Oops: 0003 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 10190 Comm: syz-executor.1 Not tainted 5.14.0-rc3-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: 68 fd 48 63 44 24 10 45 31 f6 48 89 04 24 e8 b4 8e 68 fd 31 ff 89 de 31 ed e8 e9 95 68 fd 85 db 4d 89 ec 74 22 e8 9d 8e 68 fd <45> 88 34 24 83 c5 01 89 df 49 83 c4 01 89 ee e8 b9 96 68 fd 39 eb
RSP: 0018:ffffc9000a6cf848 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 000000000000001b RCX: 0000000000000000
RDX: ffff888026d11c40 RSI: ffffffff840d0c53 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff840d05dd
R10: ffffffff840d0c47 R11: 0000000000000000 R12: ffff888001000050
R13: ffff888001000050 R14: 0000000000000000 R15: 000000000ffeb7ff
FS: 00007f96740f3700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff888001000050 CR3: 000000003d3c8000 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:1108
fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1183
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: 0033:0x4665d9
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:00007f96740f3188 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: 00007ffe8fbfd6af R14: 00007f96740f3300 R15: 0000000000022000
Modules linked in:
CR2: ffff888001000050
---[ end trace 1128197359467619 ]---
RIP: 0010:writeb arch/x86/include/asm/io.h:65 [inline]
RIP: 0010:vga16fb_fillrect+0x993/0x18d0 drivers/video/fbdev/vga16fb.c:923
Code: 68 fd 48 63 44 24 10 45 31 f6 48 89 04 24 e8 b4 8e 68 fd 31 ff 89 de 31 ed e8 e9 95 68 fd 85 db 4d 89 ec 74 22 e8 9d 8e 68 fd <45> 88 34 24 83 c5 01 89 df 49 83 c4 01 89 ee e8 b9 96 68 fd 39 eb
RSP: 0018:ffffc9000a6cf848 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 000000000000001b RCX: 0000000000000000
RDX: ffff888026d11c40 RSI: ffffffff840d0c53 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff840d05dd
R10: ffffffff840d0c47 R11: 0000000000000000 R12: ffff888001000050
R13: ffff888001000050 R14: 0000000000000000 R15: 000000000ffeb7ff
FS: 00007f96740f3700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff888001000050 CR3: 000000003d3c8000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


Tested on:

commit: 764a5bc8 Merge tag 'drm-fixes-2021-07-30' of git://ano..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15b4763e300000
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