==================================================================
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 buffer_locked include/linux/buffer_head.h:122 [inline]
BUG: KASAN: null-ptr-deref in fix_nodes+0x44d/0x8c70 fs/reiserfs/fix_node.c:2578
Read of size 8 at addr 0000000000000000 by task syz-executor.4/4800

CPU: 0 PID: 4800 Comm: syz-executor.4 Not tainted 5.15.120-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 __kasan_report mm/kasan/report.c:438 [inline]
 kasan_report+0x161/0x1c0 mm/kasan/report.c:451
 kasan_check_range+0x27e/0x290 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]
 buffer_locked include/linux/buffer_head.h:122 [inline]
 fix_nodes+0x44d/0x8c70 fs/reiserfs/fix_node.c:2578
 reiserfs_cut_from_item+0x463/0x2560 fs/reiserfs/stree.c:1742
 reiserfs_do_truncate+0xa12/0x15b0 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x638/0xda0 fs/reiserfs/inode.c:2318
 reiserfs_setattr+0xa4d/0xf90 fs/reiserfs/inode.c:3409
 notify_change+0xd4d/0x1000 fs/attr.c:488
 do_truncate+0x21c/0x300 fs/open.c:65
 handle_truncate fs/namei.c:3195 [inline]
 do_open fs/namei.c:3542 [inline]
 path_openat+0x28a0/0x2f20 fs/namei.c:3672
 do_filp_open+0x21c/0x460 fs/namei.c:3699
 do_sys_openat2+0x13b/0x500 fs/open.c:1211
 do_sys_open fs/open.c:1227 [inline]
 __do_sys_open fs/open.c:1235 [inline]
 __se_sys_open fs/open.c:1231 [inline]
 __x64_sys_open+0x221/0x270 fs/open.c:1231
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f478cf92b29
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f47842f30c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f478d0b2050 RCX: 00007f478cf92b29
RDX: 0000000000000000 RSI: 00000000001c5342 RDI: 00000000200001c0
RBP: 00007f478cfde47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f478d0b2050 R15: 00007ffcaa871bf8
 </TASK>
==================================================================