Hello, syzbot found the following issue on: HEAD commit: 148341f0a2f5 Merge tag 'vfs.misc.fixes.v6.3-rc6' of git://.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=131e7b5dc80000 kernel config: https://syzkaller.appspot.com/x/.config?x=d3500b143c204867 dashboard link: https://syzkaller.appspot.com/bug?extid=5184326923f180b9d11a 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. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/bd1a34836b5e/disk-148341f0.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/04a1edfc1dd9/vmlinux-148341f0.xz kernel image: https://storage.googleapis.com/syzbot-assets/ec7cb22838b5/bzImage-148341f0.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+5184326923f180b9d11a@xxxxxxxxxxxxxxxxxxxxxxxxx REISERFS (device loop2): Remounting filesystem read-only ================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:72 [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 buffer_locked include/linux/buffer_head.h:126 [inline] BUG: KASAN: null-ptr-deref in fix_nodes+0x464/0x8660 fs/reiserfs/fix_node.c:2578 Read of size 8 at addr 0000000000000000 by task syz-executor.2/4037 CPU: 1 PID: 4037 Comm: syz-executor.2 Not tainted 6.3.0-rc5-syzkaller-00005-g148341f0a2f5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_report mm/kasan/report.c:433 [inline] kasan_report+0xec/0x130 mm/kasan/report.c:536 check_region_inline mm/kasan/generic.c:181 [inline] kasan_check_range+0x141/0x190 mm/kasan/generic.c:187 instrument_atomic_read include/linux/instrumented.h:72 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] buffer_locked include/linux/buffer_head.h:126 [inline] fix_nodes+0x464/0x8660 fs/reiserfs/fix_node.c:2578 reiserfs_cut_from_item+0x2bd/0x1b20 fs/reiserfs/stree.c:1742 reiserfs_do_truncate+0x630/0x1080 fs/reiserfs/stree.c:1973 reiserfs_truncate_file+0x1b5/0x1070 fs/reiserfs/inode.c:2310 reiserfs_setattr+0xddf/0x1370 fs/reiserfs/inode.c:3395 notify_change+0xb2c/0x1180 fs/attr.c:482 do_truncate+0x143/0x200 fs/open.c:66 handle_truncate fs/namei.c:3219 [inline] do_open fs/namei.c:3564 [inline] path_openat+0x2083/0x2750 fs/namei.c:3715 do_filp_open+0x1ba/0x410 fs/namei.c:3742 do_sys_openat2+0x16d/0x4c0 fs/open.c:1348 do_sys_open fs/open.c:1364 [inline] __do_sys_creat fs/open.c:1440 [inline] __se_sys_creat fs/open.c:1434 [inline] __x64_sys_creat+0xcd/0x120 fs/open.c:1434 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fd96be8c169 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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:00007fd96cb5a168 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007fd96bfac1f0 RCX: 00007fd96be8c169 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000040 RBP: 00007fd96bee7ca1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcd572849f R14: 00007fd96cb5a300 R15: 0000000000022000 </TASK> ================================================================== --- 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.