================================================================== 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+0x3a4/0x490 fs/erofs/decompressor.c:346 Read of size 4096 at addr ffff0000f9077000 by task syz.4.224/5504 CPU: 1 PID: 5504 Comm: syz.4.224 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 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+0x152c/0x16cc fs/erofs/zdata.c:1603 z_erofs_read_folio+0x2d8/0x5c8 fs/erofs/zdata.c:1693 filemap_read_folio+0x134/0x384 mm/filemap.c:2490 filemap_fault+0x98c/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+0x1cac/0x2fb0 mm/memory.c:5292 __do_page_fault arch/arm64/mm/fault.c:499 [inline] do_page_fault+0x310/0x98c arch/arm64/mm/fault.c:583 do_translation_fault+0x94/0xc8 arch/arm64/mm/fault.c:667 do_mem_abort+0x70/0x194 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 Allocated by task 5423: 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_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:936 [inline] __kmalloc+0xec/0x178 mm/slab_common.c:949 kmalloc include/linux/slab.h:568 [inline] kzalloc include/linux/slab.h:699 [inline] tomoyo_encode2 security/tomoyo/realpath.c:45 [inline] tomoyo_encode+0x26c/0x49c security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x480/0x4d4 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x19c/0x35c security/tomoyo/file.c:771 tomoyo_file_open+0x128/0x198 security/tomoyo/tomoyo.c:320 security_file_open+0x6c/0xac security/security.c:1682 do_dentry_open+0x29c/0xf98 fs/open.c:869 vfs_open+0x7c/0x90 fs/open.c:1015 do_open fs/namei.c:3634 [inline] path_openat+0x1f8c/0x26bc fs/namei.c:3791 do_filp_open+0x194/0x384 fs/namei.c:3818 do_sys_openat2+0x134/0x3f4 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __arm64_sys_openat+0x118/0x14c fs/open.c:1347 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 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 Freed by task 5423: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xbc/0x218 mm/slub.c:3700 kfree+0xd0/0x1a8 mm/slab_common.c:988 tomoyo_check_open_permission+0x274/0x35c security/tomoyo/file.c:786 tomoyo_file_open+0x128/0x198 security/tomoyo/tomoyo.c:320 security_file_open+0x6c/0xac security/security.c:1682 do_dentry_open+0x29c/0xf98 fs/open.c:869 vfs_open+0x7c/0x90 fs/open.c:1015 do_open fs/namei.c:3634 [inline] path_openat+0x1f8c/0x26bc fs/namei.c:3791 do_filp_open+0x194/0x384 fs/namei.c:3818 do_sys_openat2+0x134/0x3f4 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __arm64_sys_openat+0x118/0x14c fs/open.c:1347 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 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 ffff0000f9077000 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 0 bytes inside of 128-byte region [ffff0000f9077000, ffff0000f9077080) The buggy address belongs to the physical page: page:000000003067c133 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000f9077100 pfn:0x139077 flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000200 fffffc00030ee288 fffffc0003db4b88 ffff0000c0002300 raw: ffff0000f9077100 000000000010000f 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000f9076f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff0000f9076f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff0000f9077000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000f9077080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000f9077100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================