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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 ffff0000d8de8000 by task syz.3.273/5410

CPU: 0 PID: 5410 Comm: syz.3.273 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
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:1159 [inline]
 z_erofs_decompress_queue+0x103c/0x1bf4 fs/erofs/zdata.c:1240
 z_erofs_runqueue+0x1508/0x16a8 fs/erofs/zdata.c:1603
 z_erofs_read_folio+0x2dc/0x5cc fs/erofs/zdata.c:1693
 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_read_fault mm/memory.c:4629 [inline]
 do_fault mm/memory.c:4758 [inline]
 handle_pte_fault mm/memory.c:5029 [inline]
 __handle_mm_fault mm/memory.c:5171 [inline]
 handle_mm_fault+0x1d04/0x3018 mm/memory.c:5292
 __do_page_fault arch/arm64/mm/fault.c:499 [inline]
 do_page_fault+0x310/0x99c arch/arm64/mm/fault.c:583
 do_translation_fault+0x94/0xc8 arch/arm64/mm/fault.c:667
 do_mem_abort+0x70/0x198 arch/arm64/mm/fault.c:804
 el0_da+0x70/0x144 arch/arm64/kernel/entry-common.c:515
 el0t_64_sync_handler+0x90/0xf0 arch/arm64/kernel/entry-common.c:658
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the physical page:
page:00000000314f28dd refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x118de8
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 fffffc0003f5fd08 fffffc000375c5c8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d8de7f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000d8de7f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000d8de8000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff0000d8de8080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000d8de8100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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