loop2: rw=524288, sector=16, nr_sectors = 8 limit=16
syz.2.83: attempt to access beyond end of device
loop2: rw=524288, sector=13716630376, nr_sectors = 8 limit=16
==================================================================
BUG: KASAN: use-after-free in z_erofs_transform_plain+0x374/0x480 fs/erofs/decompressor.c:350
Read of size 4095 at addr ffff0000cb3c1400 by task syz.2.83/4782

CPU: 1 PID: 4782 Comm: syz.2.83 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
 print_address_description+0x88/0x220 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:427
 kasan_report+0xa8/0x100 mm/kasan/report.c:531
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x260/0x2a0 mm/kasan/generic.c:189
 memcpy+0x48/0x90 mm/kasan/shadow.c:65
 z_erofs_transform_plain+0x374/0x480 fs/erofs/decompressor.c:350
 z_erofs_decompress+0x9c/0xd4 fs/erofs/decompressor.c:439
 z_erofs_decompress_pcluster fs/erofs/zdata.c:1175 [inline]
 z_erofs_decompress_queue+0x1054/0x1d30 fs/erofs/zdata.c:1258
 z_erofs_runqueue+0x14fc/0x1678 fs/erofs/zdata.c:1616
 z_erofs_readahead+0x898/0xc58 fs/erofs/zdata.c:1760
 read_pages+0x158/0x680 mm/readahead.c:161
 page_cache_ra_unbounded+0x498/0x57c mm/readahead.c:270
 do_page_cache_ra mm/readahead.c:300 [inline]
 force_page_cache_ra+0x248/0x2b0 mm/readahead.c:331
 force_page_cache_readahead mm/internal.h:125 [inline]
 generic_fadvise+0x32c/0x57c mm/fadvise.c:107
 vfs_fadvise mm/fadvise.c:185 [inline]
 ksys_fadvise64_64 mm/fadvise.c:199 [inline]
 __do_sys_fadvise64_64 mm/fadvise.c:207 [inline]
 __se_sys_fadvise64_64 mm/fadvise.c:205 [inline]
 __arm64_sys_fadvise64_64+0x12c/0x174 mm/fadvise.c:205
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the physical page:
page:00000000fd3686f4 refcount:2 mapcount:0 mapping:00000000dcf9c8f2 index:0x1 pfn:0x10b3c1
memcg:ffff0000d8836000
aops:managed_cache_aops ino:0
flags: 0x5ffd00000002014(uptodate|lru|private|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffd00000002014 fffffc00032a8e08 fffffc0004021fc8 ffff0000e1f517d0
raw: 0000000000000001 ffff0000df685000 00000002ffffffff ffff0000d8836000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000cb3c1f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000cb3c1f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000cb3c2000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff0000cb3c2080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000cb3c2100: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
erofs: (device loop2): erofs_find_target_block: corrupted dir block 8200 @ nid 36