syz.5.1133: attempt to access beyond end of device
loop5: rw=524288, sector=67108872, nr_sectors = 16 limit=16
syz.5.1133: attempt to access beyond end of device
loop5: rw=524288, sector=720, nr_sectors = 8 limit=16
==================================================================
BUG: KASAN: slab-out-of-bounds in z_erofs_transform_plain+0x394/0x4a0 fs/erofs/decompressor.c:350
Read of size 4095 at addr ffff88807998e400 by task syz.5.1133/10213

CPU: 1 PID: 10213 Comm: syz.5.1133 Not tainted 6.1.129-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:427
 kasan_report+0x136/0x160 mm/kasan/report.c:531
 kasan_check_range+0x27f/0x290 mm/kasan/generic.c:189
 memcpy+0x25/0x60 mm/kasan/shadow.c:65
 z_erofs_transform_plain+0x394/0x4a0 fs/erofs/decompressor.c:350
 z_erofs_decompress_pcluster fs/erofs/zdata.c:1175 [inline]
 z_erofs_decompress_queue+0x1aad/0x2d80 fs/erofs/zdata.c:1258
 z_erofs_runqueue+0x1bfe/0x1e10 fs/erofs/zdata.c:1616
 z_erofs_readahead+0xc26/0x1030 fs/erofs/zdata.c:1760
 read_pages+0x17f/0x830 mm/readahead.c:161
 page_cache_ra_unbounded+0x68b/0x7b0 mm/readahead.c:270
 do_page_cache_ra mm/readahead.c:300 [inline]
 force_page_cache_ra+0x2a3/0x300 mm/readahead.c:331
 force_page_cache_readahead mm/internal.h:125 [inline]
 generic_fadvise+0x553/0x7b0 mm/fadvise.c:107
 vfs_fadvise mm/fadvise.c:185 [inline]
 ksys_fadvise64_64 mm/fadvise.c:199 [inline]
 __do_sys_fadvise64 mm/fadvise.c:214 [inline]
 __se_sys_fadvise64 mm/fadvise.c:212 [inline]
 __x64_sys_fadvise64+0x138/0x180 mm/fadvise.c:212
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8b72b8d169
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:00007f8b73922038 EFLAGS: 00000246 ORIG_RAX: 00000000000000dd
RAX: ffffffffffffffda RBX: 00007f8b72da5fa0 RCX: 00007f8b72b8d169
RDX: 0000000000004101 RSI: 0000000000008000 RDI: 0000000000000008
RBP: 00007f8b72c0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f8b72da5fa0 R15: 00007ffddca5cc28
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001e66380 refcount:2 mapcount:0 mapping:ffff888071af9d28 index:0x1 pfn:0x7998e
memcg:ffff888057e50000
aops:managed_cache_aops ino:0
flags: 0xfff40000002014(uptodate|lru|private|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff40000002014 ffffea0001dca788 ffffea00011ca708 ffff888071af9d28
raw: 0000000000000001 ffff88805524c3a8 00000002ffffffff ffff888057e50000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x192840(GFP_NOWAIT|__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 10213, tgid 10212 (syz.5.1133), ts 536803896540, free_ts 536783392636
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x3731/0x38d0 mm/page_alloc.c:4328
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5605
 z_erofs_bind_cache fs/erofs/zdata.c:482 [inline]
 z_erofs_do_read_page+0x19df/0x3ce0 fs/erofs/zdata.c:860
 z_erofs_read_folio+0x31a/0x760 fs/erofs/zdata.c:1705
 filemap_read_folio+0x199/0x780 mm/filemap.c:2489
 do_read_cache_folio+0x2ee/0x810 mm/filemap.c:3626
 erofs_bread+0x19d/0x6b0 fs/erofs/data.c:50
 erofs_find_target_block fs/erofs/namei.c:102 [inline]
 erofs_namei+0x278/0xef0 fs/erofs/namei.c:175
 erofs_lookup+0x1d6/0x4d0 fs/erofs/namei.c:204
 lookup_open fs/namei.c:3460 [inline]
 open_last_lookups fs/namei.c:3550 [inline]
 path_openat+0x10fb/0x2e60 fs/namei.c:3780
 do_filp_open+0x230/0x480 fs/namei.c:3810
 do_sys_openat2+0x13b/0x4f0 fs/open.c:1318
 do_sys_open fs/open.c:1334 [inline]
 __do_sys_creat fs/open.c:1412 [inline]
 __se_sys_creat fs/open.c:1406 [inline]
 __x64_sys_creat+0x11f/0x160 fs/open.c:1406
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x12a6/0x15b0 mm/page_alloc.c:3384
 free_unref_page+0x33/0x3e0 mm/page_alloc.c:3479
 free_slab mm/slub.c:2031 [inline]
 discard_slab mm/slub.c:2037 [inline]
 __unfreeze_partials+0x1b7/0x210 mm/slub.c:2586
 put_cpu_partial+0x17b/0x250 mm/slub.c:2662
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x156/0x170 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x1f/0x70 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737
 slab_alloc_node mm/slub.c:3398 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422
 getname_flags+0xb8/0x4f0 fs/namei.c:139
 user_path_at_empty+0x28/0x60 fs/namei.c:2904
 do_readlinkat+0x114/0x3a0 fs/stat.c:468
 __do_sys_readlink fs/stat.c:501 [inline]
 __se_sys_readlink fs/stat.c:498 [inline]
 __x64_sys_readlink+0x7b/0x90 fs/stat.c:498
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88807998ef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807998f000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88807998f080: 00 00 00 00 00 fc fc fc fc fc fc fc fc 00 00 00
                                  ^
 ffff88807998f100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807998f180: 00 00 fc fc fc fc fc fc fc fc 00 00 00 00 00 00
==================================================================