[syzbot] [btrfs?] [fbdev?] BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs (3)

Tue Sep 10 08:17:27 UTC 2024

Hello,

syzbot found the following issue on:

HEAD commit:    da3ea35007d0 Linux 6.11-rc7
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15662a8b980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=61d235cb8d15001c
dashboard link: https://syzkaller.appspot.com/bug?extid=3d613ae53c031502687a
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12221420580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1133a797980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-da3ea350.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1ab780d224f6/vmlinux-da3ea350.xz
kernel image: https://storage.googleapis.com/syzbot-assets/834dde85c1c2/bzImage-da3ea350.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/f56cd5277a08/mount_8.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3d613ae53c031502687a at syzkaller.appspotmail.com

BTRFS info (device loop0): disabling free space tree
BTRFS info (device loop0): clearing compat-ro feature flag for FREE_SPACE_TREE (0x1)
BTRFS info (device loop0): clearing compat-ro feature flag for FREE_SPACE_TREE_VALID (0x2)
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 357e5067 P4D 357e5067 PUD 3c1d6067 PMD 0 
Oops: Oops: 0010 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5093 Comm: syz-executor182 Not tainted 6.11.0-rc7-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc90002c5f6b8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88801acc9000 RCX: 0000000000000001
RDX: ffff888033fd413e RSI: ffff88801f5cb000 RDI: ffff88801acc9000
RBP: 1ffff110067fa827 R08: 0000000000000000 R09: 000000000000009f
R10: 0000000000000002 R11: 0000000000000000 R12: ffff88801f5cb000
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888033fd413e
FS:  0000555586260380(0000) GS:ffff88801fe00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000409ee000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 fbcon_putcs+0x255/0x390 drivers/video/fbdev/core/fbcon.c:1288
 do_update_region+0x396/0x450 drivers/tty/vt/vt.c:619
 invert_screen+0x401/0xe50 drivers/tty/vt/vt.c:740
 highlight drivers/tty/vt/selection.c:57 [inline]
 clear_selection+0x59/0x80 drivers/tty/vt/selection.c:87
 vc_do_resize+0x6e6/0x17f0 drivers/tty/vt/vt.c:1187
 vc_resize include/linux/vt_kern.h:49 [inline]
 fbcon_set_disp+0xac9/0x11d0 drivers/video/fbdev/core/fbcon.c:1389
 con2fb_init_display drivers/video/fbdev/core/fbcon.c:794 [inline]
 set_con2fb_map+0xa6c/0x10a0 drivers/video/fbdev/core/fbcon.c:865
 fbcon_set_con2fb_map_ioctl+0x207/0x320 drivers/video/fbdev/core/fbcon.c:3092
 do_fb_ioctl+0x38f/0x7b0 drivers/video/fbdev/core/fb_chrdev.c:138
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7cf95f6fa9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdb38b4c58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 7573617461646f6e RCX: 00007f7cf95f6fa9
RDX: 00000000200000c0 RSI: 0000000000004610 RDI: 0000000000000003
RBP: 00007f7cf96705f0 R08: 00005555862614c0 R09: 00005555862614c0
R10: 00005555862614c0 R11: 0000000000000246 R12: 00007ffdb38b4c80
R13: 00007ffdb38b4ea8 R14: 431bde82d7b634db R15: 00007f7cf964001d
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc90002c5f6b8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88801acc9000 RCX: 0000000000000001
RDX: ffff888033fd413e RSI: ffff88801f5cb000 RDI: ffff88801acc9000
RBP: 1ffff110067fa827 R08: 0000000000000000 R09: 000000000000009f
R10: 0000000000000002 R11: 0000000000000000 R12: ffff88801f5cb000
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888033fd413e
FS:  0000555586260380(0000) GS:ffff88801fe00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000409ee000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

---
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