syz.4.252: attempt to access beyond end of device loop4: rw=524288, sector=16, nr_sectors = 8 limit=16 syz.4.252: attempt to access beyond end of device loop4: rw=524288, sector=13716630376, nr_sectors = 8 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 4095 at addr ffff888023c20400 by task syz.4.252/7562 CPU: 0 PID: 7562 Comm: syz.4.252 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xac/0x220 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+0x288/0x290 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+0x16fb/0x2660 fs/erofs/zdata.c:1377 z_erofs_runqueue+0x18a3/0x19d0 fs/erofs/zdata.c:1774 z_erofs_readahead+0xa7c/0xd50 fs/erofs/zdata.c:1903 read_pages+0x177/0x840 mm/readahead.c:160 page_cache_ra_unbounded+0x692/0x770 mm/readahead.c:269 do_page_cache_ra mm/readahead.c:299 [inline] force_page_cache_ra+0x2c1/0x320 mm/readahead.c:330 force_page_cache_readahead mm/internal.h:175 [inline] generic_fadvise+0x44f/0x730 mm/fadvise.c:106 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+0x140/0x180 mm/fadvise.c:212 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fd1f8d8f749 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:00007fd1f9d18038 EFLAGS: 00000246 ORIG_RAX: 00000000000000dd RAX: ffffffffffffffda RBX: 00007fd1f8fe5fa0 RCX: 00007fd1f8d8f749 RDX: 000000000000ff39 RSI: 000000000000aa17 RDI: 0000000000000005 RBP: 00007fd1f8e13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd1f8fe6038 R14: 00007fd1f8fe5fa0 R15: 00007ffc8750a548 The buggy address belongs to the physical page: page:ffffea00008f0800 refcount:2 mapcount:0 mapping:ffff88805d980270 index:0x1 pfn:0x23c20 memcg:ffff8880265f2000 aops:z_erofs_cache_aops ino:0 flags: 0xfff40000008028(uptodate|lru|private|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff40000008028 ffffea0001e2e308 ffffea00017e6dc8 ffff88805d980270 raw: 0000000000000001 ffff888055062178 00000002ffffffff ffff8880265f2000 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 7569, tgid 7561 (syz.4.252), ts 259295435612, free_ts 259225620380 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554 prep_new_page mm/page_alloc.c:1561 [inline] get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457 z_erofs_bind_cache fs/erofs/zdata.c:605 [inline] z_erofs_pcluster_begin fs/erofs/zdata.c:889 [inline] z_erofs_do_read_page+0x20c0/0x3680 fs/erofs/zdata.c:1024 z_erofs_read_folio+0x213/0x540 fs/erofs/zdata.c:1854 filemap_read_folio+0x167/0x760 mm/filemap.c:2420 do_read_cache_folio+0x470/0x7e0 mm/filemap.c:3804 erofs_bread+0x16f/0x630 fs/erofs/data.c:48 erofs_find_target_block fs/erofs/namei.c:103 [inline] erofs_namei+0x28c/0xf00 fs/erofs/namei.c:177 erofs_lookup+0x135/0x310 fs/erofs/namei.c:206 __lookup_slow+0x281/0x3b0 fs/namei.c:1702 lookup_slow+0x53/0x70 fs/namei.c:1719 walk_component+0x2be/0x3f0 fs/namei.c:2010 lookup_last fs/namei.c:2467 [inline] path_lookupat+0x169/0x440 fs/namei.c:2491 filename_lookup+0x1f4/0x510 fs/namei.c:2520 user_path_at_empty+0x42/0x60 fs/namei.c:2917 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1154 [inline] free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429 vfree+0x1a6/0x320 mm/vmalloc.c:2868 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:2788 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Memory state around the buggy address: ffff888023c20f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888023c20f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888023c21000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888023c21080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888023c21100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================