syzbot


BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs (3)

Status: upstream: reported C repro on 2024/09/10 08:17
Subsystems: btrfs fbdev
[Documentation on labels]
Reported-by: syzbot+3d613ae53c031502687a@syzkaller.appspotmail.com
Fix commit: 5b97eebcce1b fbcon: Fix a NULL pointer dereference issue in fbcon_putcs
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu-native-arm64-kvm ci-upstream-bpf-kasan-gce]
First crash: 27d, last: 14d
Discussions (8)
Title Replies (including bot) Last reply
[PATCH AUTOSEL 6.1 41/42] fbcon: Fix a NULL pointer dereference issue in fbcon_putcs 1 (1) 2024/10/04 18:26
[PATCH AUTOSEL 6.6 56/58] fbcon: Fix a NULL pointer dereference issue in fbcon_putcs 1 (1) 2024/10/04 18:24
[PATCH AUTOSEL 6.10 68/70] fbcon: Fix a NULL pointer dereference issue in fbcon_putcs 1 (1) 2024/10/04 18:21
[PATCH AUTOSEL 6.11 74/76] fbcon: Fix a NULL pointer dereference issue in fbcon_putcs 1 (1) 2024/10/04 18:17
[PATCH] fbcon: Fix a NULL pointer dereference issue in fbcon_putcs 7 (7) 2024/09/25 19:33
Re: [syzbot] [btrfs?] [fbdev?] BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs (3) 1 (2) 2024/09/24 15:15
[PATCH] fbcon: Fix a NULL pointer dereference issue in fbcon_putcs 1 (1) 2024/09/17 07:28
[syzbot] [btrfs?] [fbdev?] BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs (3) 0 (2) 2024/09/16 00:46
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs fbdev 2 1199d 1217d 0/28 auto-closed as invalid on 2021/10/24 09:10
upstream BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs (2) fbdev 1 1059d 1055d 0/28 auto-closed as invalid on 2022/02/11 07:43
Last patch testing requests (2)
Created Duration User Patch Repo Result
2024/09/24 14:52 21m qianqiang.liu@163.com patch upstream OK log
2024/09/16 00:46 20m qianqiang.liu@163.com patch upstream OK log

Sample crash report:
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

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/09 22:47 upstream da3ea35007d0 8f722c94 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs
2024/09/09 20:09 upstream da3ea35007d0 8f722c94 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs
2024/09/23 06:29 upstream af9c191ac2a0 6f888b75 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs
2024/09/09 18:55 upstream da3ea35007d0 8f722c94 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs
* Struck through repros no longer work on HEAD.