loop3: rw=524288, sector=88, nr_sectors = 48 limit=16
syz.3.84: attempt to access beyond end of device
loop3: rw=524288, sector=8, nr_sectors = 80 limit=16
==================================================================
BUG: KASAN: use-after-free in memcpy_to_page include/linux/highmem.h:403 [inline]
BUG: KASAN: use-after-free in z_erofs_transform_plain+0x39c/0x494 fs/erofs/decompressor.c:347
Read of size 4096 at addr ffff0000cd344000 by task syz.3.84/4690

CPU: 1 PID: 4690 Comm: syz.3.84 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026
Call trace:
 dump_backtrace+0x1c4/0x1f0 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+0x39c/0x494 fs/erofs/decompressor.c:347
 z_erofs_decompress+0x9c/0xd4 fs/erofs/decompressor.c:435
 z_erofs_decompress_pcluster fs/erofs/zdata.c:1161 [inline]
 z_erofs_decompress_queue+0x103c/0x1bf4 fs/erofs/zdata.c:1242
 z_erofs_runqueue+0x1508/0x16a8 fs/erofs/zdata.c:1614
 z_erofs_read_folio+0x2dc/0x5cc fs/erofs/zdata.c:1704
 filemap_read_folio+0x134/0x384 mm/filemap.c:2490
 filemap_fault+0x990/0xe98 mm/filemap.c:3340
 __do_fault+0x11c/0x3d8 mm/memory.c:4278
 do_cow_fault mm/memory.c:4659 [inline]
 do_fault mm/memory.c:4760 [inline]
 handle_pte_fault mm/memory.c:5029 [inline]
 __handle_mm_fault mm/memory.c:5171 [inline]
 handle_mm_fault+0x18d8/0x3018 mm/memory.c:5292
 faultin_page mm/gup.c:1026 [inline]
 __get_user_pages+0x340/0x770 mm/gup.c:1250
 populate_vma_page_range+0x1f4/0x298 mm/gup.c:1607
 mprotect_fixup+0x578/0x610 mm/mprotect.c:655
 do_mprotect_pkey mm/mprotect.c:792 [inline]
 __do_sys_mprotect mm/mprotect.c:819 [inline]
 __se_sys_mprotect mm/mprotect.c:816 [inline]
 __arm64_sys_mprotect+0x5f0/0xa10 mm/mprotect.c:816
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c 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:589

The buggy address belongs to the physical page:
page:00000000920e9d4c refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x10d344
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 fffffc0003350e08 fffffc0003134b88 0000000000000000
raw: 0000000000000000 0000000000000001 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000cd343f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000cd343f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000cd344000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff0000cd344080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000cd344100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
syz.3.84: attempt to access beyond end of device
loop3: rw=0, sector=34359738360, nr_sectors = 8 limit=16