loop4: rw=524288, sector=34359738360, nr_sectors = 8 limit=16 syz.4.668: attempt to access beyond end of device loop4: rw=524288, sector=88, nr_sectors = 48 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 ffff0000ef80b000 by task syz.4.668/7521 CPU: 1 PID: 7521 Comm: syz.4.668 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026 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_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+0x58/0x128 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 7422: 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+0x234/0x310 mm/slub.c:3383 ptlock_alloc mm/memory.c:6045 [inline] ptlock_init include/linux/mm.h:2480 [inline] pgtable_pte_page_ctor include/linux/mm.h:2507 [inline] __pte_alloc_one include/asm-generic/pgalloc.h:66 [inline] pte_alloc_one+0x78/0x254 include/asm-generic/pgalloc.h:85 __pte_alloc mm/memory.c:468 [inline] copy_pte_range mm/memory.c:1042 [inline] copy_pmd_range mm/memory.c:1177 [inline] copy_pud_range mm/memory.c:1214 [inline] copy_p4d_range mm/memory.c:1238 [inline] copy_page_range+0x223c/0x29b4 mm/memory.c:1332 dup_mmap kernel/fork.c:703 [inline] dup_mm kernel/fork.c:1548 [inline] copy_mm+0xb08/0x1208 kernel/fork.c:1597 copy_process+0x1718/0x38f4 kernel/fork.c:2358 kernel_clone+0x1ec/0x938 kernel/fork.c:2765 __do_sys_clone kernel/fork.c:2906 [inline] __se_sys_clone kernel/fork.c:2874 [inline] __arm64_sys_clone+0x15c/0x1c8 kernel/fork.c:2874 __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+0x58/0x128 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 7426: 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+0x118/0x318 mm/slub.c:3709 ptlock_free mm/memory.c:6054 [inline] pgtable_pte_page_dtor+0x58/0x1c8 include/linux/mm.h:2516 __pte_free_tlb arch/arm64/include/asm/tlb.h:78 [inline] free_pte_range mm/memory.c:226 [inline] free_pmd_range mm/memory.c:244 [inline] free_pud_range mm/memory.c:278 [inline] free_p4d_range mm/memory.c:312 [inline] free_pgd_range+0x4d0/0xb00 mm/memory.c:392 free_pgtables+0x2d8/0x348 mm/memory.c:-1 exit_mmap+0x2a0/0x944 mm/mmap.c:3260 __mmput+0xe8/0x38c kernel/fork.c:1206 mmput+0x70/0xa8 kernel/fork.c:1228 exit_mm+0x20c/0x290 kernel/exit.c:572 do_exit+0x4d0/0x19ac kernel/exit.c:874 do_group_exit+0x198/0x238 kernel/exit.c:1030 __do_sys_exit_group kernel/exit.c:1041 [inline] __se_sys_exit_group kernel/exit.c:1039 [inline] __wake_up_parent+0x0/0x60 kernel/exit.c:1039 __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+0x58/0x128 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 ffff0000ef80b000 which belongs to the cache page->ptl of size 64 The buggy address is located 0 bytes inside of 64-byte region [ffff0000ef80b000, ffff0000ef80b040) The buggy address belongs to the physical page: page:0000000056506f4f refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12f80b flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000200 0000000000000000 dead000000000122 ffff0000c000cd80 raw: 0000000000000000 00000000002a002a 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000ef80af00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff0000ef80af80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff0000ef80b000: fa fb fb fb fb fb fb fb fc fc fc fc fa fb fb fb ^ ffff0000ef80b080: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb ffff0000ef80b100: fc fc fc fc fa fb fb fb fb fb fb fb fc fc fc fc ==================================================================