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BUG: KASAN: vmalloc-out-of-bounds in scan_bitmap fs/reiserfs/bitmap.c:388 [inline]
BUG: KASAN: vmalloc-out-of-bounds in allocate_without_wrapping_disk fs/reiserfs/bitmap.c:1161 [inline]
BUG: KASAN: vmalloc-out-of-bounds in blocknrs_and_prealloc_arrays_from_search_start fs/reiserfs/bitmap.c:1274 [inline]
BUG: KASAN: vmalloc-out-of-bounds in reiserfs_allocate_blocknrs+0x3581/0x53b0 fs/reiserfs/bitmap.c:1375
Read of size 4 at addr ffffc9000121e004 by task syz.1.103/4683

CPU: 1 PID: 4683 Comm: syz.1.103 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 scan_bitmap fs/reiserfs/bitmap.c:388 [inline]
 allocate_without_wrapping_disk fs/reiserfs/bitmap.c:1161 [inline]
 blocknrs_and_prealloc_arrays_from_search_start fs/reiserfs/bitmap.c:1274 [inline]
 reiserfs_allocate_blocknrs+0x3581/0x53b0 fs/reiserfs/bitmap.c:1375
 reiserfs_new_form_blocknrs fs/reiserfs/reiserfs.h:3341 [inline]
 get_empty_nodes+0x407/0x8c0 fs/reiserfs/fix_node.c:879
 fix_nodes+0x1e69/0x82d0 fs/reiserfs/fix_node.c:2662
 reiserfs_paste_into_item+0x5c8/0x7e0 fs/reiserfs/stree.c:2130
 reiserfs_get_block+0x1bde/0x4100 fs/reiserfs/inode.c:1077
 __block_write_begin_int+0x54e/0x15a0 fs/buffer.c:2012
 reiserfs_write_begin+0x34b/0x810 fs/reiserfs/inode.c:2790
 generic_cont_expand_simple+0xe9/0x190 fs/buffer.c:2362
 reiserfs_setattr+0x42f/0x1010 fs/reiserfs/inode.c:3319
 notify_change+0xbcd/0xee0 fs/attr.c:505
 do_truncate+0x197/0x220 fs/open.c:65
 vfs_truncate+0x262/0x2f0 fs/open.c:111
 do_sys_truncate+0xdc/0x190 fs/open.c:134
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f66a95a7be9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f66a77ee038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f66a97df090 RCX: 00007f66a95a7be9
RDX: 0000000000000000 RSI: 0000000008800000 RDI: 0000200000000280
RBP: 00007f66a962ae19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f66a97df128 R14: 00007f66a97df090 R15: 00007fff89ad49a8
 </TASK>


Memory state around the buggy address:
 ffffc9000121df00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc9000121df80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc9000121e000: 04 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc9000121e080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc9000121e100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
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