loop1: rw=524288, sector=1056, nr_sectors = 16 limit=16
syz.1.74: attempt to access beyond end of device
loop1: rw=524288, sector=8, nr_sectors = 16 limit=16
==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy_to_page include/linux/highmem.h:403 [inline]
BUG: KASAN: slab-out-of-bounds in z_erofs_transform_plain+0x3a4/0x490 fs/erofs/decompressor.c:346
Read of size 4096 at addr ffff0000c2e56000 by task syz.1.74/4700

CPU: 1 PID: 4700 Comm: syz.1.74 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
Call trace:
 dump_backtrace+0x1c0/0x1ec 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+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x258/0x290 mm/kasan/generic.c:189
 memcpy+0x48/0x90 mm/kasan/shadow.c:65
 memcpy_to_page include/linux/highmem.h:403 [inline]
 z_erofs_transform_plain+0x3a4/0x490 fs/erofs/decompressor.c:346
 z_erofs_decompress+0x9c/0xd4 fs/erofs/decompressor.c:434
 z_erofs_decompress_pcluster fs/erofs/zdata.c:1159 [inline]
 z_erofs_decompress_queue+0x100c/0x1b40 fs/erofs/zdata.c:1240
 z_erofs_runqueue+0x14d4/0x1694 fs/erofs/zdata.c:1597
 z_erofs_read_folio+0x2d8/0x5c8 fs/erofs/zdata.c:1687
 filemap_read_folio+0x134/0x384 mm/filemap.c:2490
 filemap_update_page mm/filemap.c:2575 [inline]
 filemap_get_pages mm/filemap.c:2689 [inline]
 filemap_read+0x12cc/0x2104 mm/filemap.c:2759
 generic_file_read_iter+0xf8/0x5c4 mm/filemap.c:2941
 call_read_iter include/linux/fs.h:2259 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x3d4/0x7f0 fs/read_write.c:470
 ksys_read+0x12c/0x224 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __arm64_sys_read+0x7c/0x90 fs/read_write.c:621
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 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

Allocated by task 4330:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
 __kasan_slab_alloc+0x70/0x88 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x74/0x430 mm/slab.h:737
 slab_alloc_node mm/slub.c:3359 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x22c/0x308 mm/slub.c:3383
 kmem_cache_zalloc include/linux/slab.h:689 [inline]
 alloc_vfsmnt+0x34/0x490 fs/namespace.c:207
 clone_mnt+0x78/0xb3c fs/namespace.c:1109
 copy_tree+0x394/0x9cc fs/namespace.c:1928
 __do_loopback+0x18c/0x314 fs/namespace.c:2435
 do_loopback+0x2e0/0x3cc fs/namespace.c:2475
 path_mount+0x4d4/0xe80 fs/namespace.c:3402
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount fs/namespace.c:3606 [inline]
 __arm64_sys_mount+0x49c/0x59c fs/namespace.c:3606
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 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 object at ffff0000c2e56000
 which belongs to the cache mnt_cache of size 320
The buggy address is located 0 bytes inside of
 320-byte region [ffff0000c2e56000, ffff0000c2e56140)

The buggy address belongs to the physical page:
page:00000000e81ba08b refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000c2e57c80 pfn:0x102e56
head:00000000e81ba08b order:1 compound_mapcount:0 compound_pincount:0
memcg:ffff0000c31b1401
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 fffffc0003628780 dead000000000002 ffff0000c03dc900
raw: ffff0000c2e57c80 000000008015000f 00000001ffffffff ffff0000c31b1401
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000c2e56000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000c2e56080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000c2e56100: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
                                           ^
 ffff0000c2e56180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000c2e56200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
syz.1.74: attempt to access beyond end of device
loop1: rw=0, sector=1056, nr_sectors = 8 limit=16