erofs: (device loop3): mounted with root inode @ nid 36.
syz.3.16: attempt to access beyond end of device
loop3: rw=524288, sector=8, nr_sectors = 24 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 ffff88807bc35000 by task syz.3.16/5914

CPU: 1 PID: 5914 Comm: syz.3.16 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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+0x1913/0x1aa0 fs/erofs/zdata.c:1774
 z_erofs_read_folio+0x323/0x5c0 fs/erofs/zdata.c:1859
 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: 0033:0x7fee7c39c799
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:00007fee7d288028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fee7c615fa0 RCX: 00007fee7c39c799
RDX: 0000000000121140 RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007fee7c432bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000013d R11: 0000000000000246 R12: 0000000000000000
R13: 00007fee7c616038 R14: 00007fee7c615fa0 R15: 00007ffef72b8738
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001ef0d40 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7bc35
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 ffffea0001ef0c88 ffffea000083d388 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 0x152c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 5869, tgid 5868 (syz.2.11), ts 97948840640, free_ts 98324052605
 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:4486
 folio_alloc+0x1e/0x30 mm/mempolicy.c:2291
 filemap_alloc_folio+0xdf/0x490 mm/filemap.c:1004
 page_cache_ra_unbounded+0x17b/0x770 mm/readahead.c:247
 filemap_readahead mm/filemap.c:2569 [inline]
 filemap_get_pages+0x68c/0x1e90 mm/filemap.c:2610
 filemap_splice_read+0x3a6/0xa30 mm/filemap.c:2966
 splice_direct_to_actor+0x26b/0x8c0 fs/splice.c:1069
 do_splice_direct+0x1d5/0x2f0 fs/splice.c:1194
 do_sendfile+0x5f2/0xef0 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64+0x145/0x1a0 fs/read_write.c:1308
 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
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
 blkdev_release+0x84/0x90 block/fops.c:604
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 get_signal+0x1235/0x13f0 kernel/signal.c:2678
 arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 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:
 ffff88807bc34f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807bc34f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88807bc35000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88807bc35080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807bc35100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================