Hello, syzbot found the following issue on: HEAD commit: 9c0c4d24ac00 Merge tag 'block-5.15-2021-10-22' of git://gi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=130d1b0cb00000 kernel config: https://syzkaller.appspot.com/x/.config?x=be398dd7862f4b36 dashboard link: https://syzkaller.appspot.com/bug?extid=f0a07c0d7dae72a221d5 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+f0a07c0d7dae72a221d5@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:71 [inline] BUG: KASAN: null-ptr-deref in test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] BUG: KASAN: null-ptr-deref in set_buffer_uptodate include/linux/buffer_head.h:120 [inline] BUG: KASAN: null-ptr-deref in do_journal_end+0x12da/0x4950 fs/reiserfs/journal.c:4077 Read of size 8 at addr 0000000000000000 by task syz-executor.0/3707 CPU: 1 PID: 3707 Comm: syz-executor.0 Not tainted 5.15.0-rc6-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 __kasan_report mm/kasan/report.c:446 [inline] kasan_report.cold+0x66/0xdf mm/kasan/report.c:459 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 instrument_atomic_read include/linux/instrumented.h:71 [inline] test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] set_buffer_uptodate include/linux/buffer_head.h:120 [inline] do_journal_end+0x12da/0x4950 fs/reiserfs/journal.c:4077 reiserfs_sync_fs+0xf8/0x120 fs/reiserfs/super.c:78 __sync_filesystem fs/sync.c:39 [inline] sync_filesystem fs/sync.c:64 [inline] sync_filesystem+0x105/0x260 fs/sync.c:48 generic_shutdown_super+0x70/0x370 fs/super.c:448 kill_block_super+0x97/0xf0 fs/super.c:1395 deactivate_locked_super+0x94/0x160 fs/super.c:335 deactivate_super+0xad/0xd0 fs/super.c:366 cleanup_mnt+0x3a2/0x540 fs/namespace.c:1137 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:175 [inline] exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f0ba0b36ea7 Code: ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 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 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff63b1eb68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f0ba0b36ea7 RDX: 00007fff63b1ec3b RSI: 0000000000000002 RDI: 00007fff63b1ec30 RBP: 00007fff63b1ec30 R08: 00000000ffffffff R09: 00007fff63b1ea00 R10: 0000555556184893 R11: 0000000000000246 R12: 00007f0ba0b8f035 R13: 00007fff63b1fcf0 R14: 0000555556184810 R15: 00007fff63b1fd30 ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.