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KASAN: null-ptr-deref Read in do_journal_end

Status: upstream: reported C repro on 2025/08/05 01:55
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+c6491824ba4027804128@syzkaller.appspotmail.com
First crash: 10d, last: 6d21h
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/08/09 linux-6.6.y (ToT) 3a8ababb8b6a C [report] KASAN: null-ptr-deref Read in do_journal_end
2025/08/09 upstream (ToT) 37816488247d C Didn't crash
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 BUG: unable to handle kernel paging request in do_journal_end origin:upstream missing-backport 11 C error 18 11d 725d 0/3 upstream: reported C repro on 2023/08/21 09:50
upstream KASAN: null-ptr-deref Read in do_journal_end (2) fs 15 C error done 40699 585d 1112d 0/29 auto-obsoleted due to no activity on 2024/03/18 13:22
linux-5.15 KASAN: null-ptr-deref Read in do_journal_end missing-backport origin:upstream 11 C error 63 10d 862d 0/3 upstream: reported C repro on 2023/04/06 14:35
upstream KASAN: null-ptr-deref Read in do_journal_end fs 11 1 1392d 1387d 0/29 auto-closed as invalid on 2022/02/20 18:03
linux-4.19 general protection fault in do_journal_end reiserfs 2 C error 3 941d 989d 0/1 upstream: reported C repro on 2022/11/30 04:17
linux-4.14 general protection fault in do_journal_end reiserfs 2 C 2 916d 953d 0/1 upstream: reported C repro on 2023/01/05 12:44

Sample crash report:
==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: null-ptr-deref in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: null-ptr-deref in set_buffer_uptodate include/linux/buffer_head.h:149 [inline]
BUG: KASAN: null-ptr-deref in do_journal_end+0x10cf/0x4860 fs/reiserfs/journal.c:4086
Read of size 8 at addr 0000000000000000 by task syz-executor/5901

CPU: 1 PID: 5901 Comm: syz-executor Not tainted 6.6.101-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x288/0x290 mm/kasan/generic.c:187
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 set_buffer_uptodate include/linux/buffer_head.h:149 [inline]
 do_journal_end+0x10cf/0x4860 fs/reiserfs/journal.c:4086
 reiserfs_sync_fs+0xd0/0x150 fs/reiserfs/super.c:78
 sync_filesystem+0xea/0x220 fs/sync.c:56
 generic_shutdown_super+0x6f/0x2b0 fs/super.c:666
 kill_block_super+0x44/0x90 fs/super.c:1660
 deactivate_locked_super+0x97/0x100 fs/super.c:481
 cleanup_mnt+0x429/0x4c0 fs/namespace.c:1250
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f33f498fe97
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffdd12ac418 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f33f4a11bdd RCX: 00007f33f498fe97
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffdd12ac4d0
RBP: 00007ffdd12ac4d0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffdd12ad560
R13: 00007f33f4a11bdd R14: 000000000001482e R15: 00007ffdd12ad5a0
 </TASK>
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/05 08:35 linux-6.6.y 3a8ababb8b6a f5bcc8dc .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-linux-6-6-kasan KASAN: null-ptr-deref Read in do_journal_end
2025/08/05 01:58 linux-6.6.y 3a8ababb8b6a f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: null-ptr-deref Read in do_journal_end
2025/08/05 01:57 linux-6.6.y 3a8ababb8b6a f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: null-ptr-deref Read in do_journal_end
2025/08/05 01:57 linux-6.6.y 3a8ababb8b6a f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: null-ptr-deref Read in do_journal_end
2025/08/05 01:55 linux-6.6.y 3a8ababb8b6a f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: null-ptr-deref Read in do_journal_end
2025/08/05 01:55 linux-6.6.y 3a8ababb8b6a f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: null-ptr-deref Read in do_journal_end
* Struck through repros no longer work on HEAD.