syz.0.871: attempt to access beyond end of device
loop0: rw=524288, sector=16, nr_sectors = 40 limit=16
==================================================================
BUG: KASAN: use-after-free in memcpy_to_page include/linux/highmem.h:427 [inline]
BUG: KASAN: use-after-free in z_erofs_transform_plain+0x38c/0x460 fs/erofs/decompressor.c:346
Read of size 4096 at addr ffff888024cae000 by task syz.0.871/8846

CPU: 0 PID: 8846 Comm: syz.0.871 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x241/0x290 mm/kasan/generic.c:187
 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
 memcpy_to_page include/linux/highmem.h:427 [inline]
 z_erofs_transform_plain+0x38c/0x460 fs/erofs/decompressor.c:346
 z_erofs_decompress_pcluster fs/erofs/zdata.c:1296 [inline]
 z_erofs_decompress_queue+0x1780/0x26f0 fs/erofs/zdata.c:1377
 z_erofs_runqueue+0x1a4e/0x1bf0 fs/erofs/zdata.c:1778
 z_erofs_read_folio+0x323/0x5c0 fs/erofs/zdata.c:1863
 filemap_read_folio+0x172/0x760 mm/filemap.c:2420
 filemap_update_page mm/filemap.c:2504 [inline]
 filemap_get_pages+0x13c7/0x1e90 mm/filemap.c:2618
 filemap_read+0x402/0xf00 mm/filemap.c:2690
 __kernel_read+0x2f3/0x710 fs/read_write.c:428
 integrity_kernel_read+0x8a/0xd0 security/integrity/iint.c:221
 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:485 [inline]
 ima_calc_file_shash security/integrity/ima/ima_crypto.c:516 [inline]
 ima_calc_file_hash+0x91d/0x1910 security/integrity/ima/ima_crypto.c:573
 ima_collect_measurement+0x4d4/0xa20 security/integrity/ima/ima_api.c:290
 process_measurement+0x128e/0x1d70 security/integrity/ima/ima_main.c:370
 ima_file_check+0xcc/0x110 security/integrity/ima/ima_main.c:568
 do_open fs/namei.c:3642 [inline]
 path_openat+0x28b7/0x3230 fs/namei.c:3797
 do_filp_open+0x1f5/0x430 fs/namei.c:3824
 do_sys_openat2+0x134/0x1d0 fs/open.c:1421
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_openat fs/open.c:1452 [inline]
 __se_sys_openat fs/open.c:1447 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8581f9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8582dfa028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f8582215fa0 RCX: 00007f8581f9c819
RDX: 0000000000080000 RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f8582032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8582216038 R14: 00007f8582215fa0 R15: 00007ffe643d5bb8
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0000932b80 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24cae
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 ffffea0001441348 ffffea0001e97108 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x140c40(GFP_NOFS|__GFP_COMP|__GFP_HARDWALL), pid 8840, tgid 8839 (syz.2.869), ts 486583318264, free_ts 486684496946
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1581
 prep_new_page mm/page_alloc.c:1588 [inline]
 get_page_from_freelist+0x1951/0x19e0 mm/page_alloc.c:3220
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4500
 folio_alloc+0x1e/0x30 mm/mempolicy.c:2289
 filemap_alloc_folio+0xdf/0x490 mm/filemap.c:1004
 do_read_cache_folio+0x364/0x7d0 mm/filemap.c:3773
 erofs_bread+0x16f/0x630 fs/erofs/data.c:48
 erofs_xattr_iter_shared+0x20e/0x3e0 fs/erofs/xattr.c:378
 erofs_getxattr+0x2dc/0x460 fs/erofs/xattr.c:432
 erofs_get_acl+0x7a/0x150 fs/erofs/xattr.c:543
 __get_acl+0x273/0x400 fs/posix_acl.c:160
 check_acl+0x3a/0x150 fs/namei.c:310
 acl_permission_check fs/namei.c:355 [inline]
 generic_permission+0x381/0x590 fs/namei.c:408
 do_inode_permission fs/namei.c:469 [inline]
 inode_permission+0x94/0x480 fs/namei.c:529
 may_open+0x2e9/0x440 fs/namei.c:3268
 do_open fs/namei.c:3638 [inline]
 path_openat+0x268c/0x3230 fs/namei.c:3797
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1181 [inline]
 free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2365
 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2504
 release_pages+0x1f7a/0x2200 mm/swap.c:1022
 __folio_batch_release+0x71/0xe0 mm/swap.c:1042
 folio_batch_release include/linux/pagevec.h:83 [inline]
 truncate_inode_pages_range+0x3b9/0xfb0 mm/truncate.c:396
 kill_bdev block/bdev.c:76 [inline]
 blkdev_flush_mapping+0x132/0x290 block/bdev.c:649
 blkdev_put_whole block/bdev.c:680 [inline]
 blkdev_put+0x498/0x760 block/bdev.c:958
 bdev_release+0x57/0x70 block/bdev.c:968
 erofs_kill_sb+0x4c/0x140 fs/erofs/super.c:794
 deactivate_locked_super+0x97/0x100 fs/super.c:481
 cleanup_mnt+0x43b/0x4d0 fs/namespace.c:1259
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82

Memory state around the buggy address:
 ffff888024cadf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888024cadf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888024cae000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888024cae080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888024cae100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================