loop1: rw=524288, sector=88, nr_sectors = 48 limit=16 syz.1.299: attempt to access beyond end of device loop1: 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 ffff0000f2757000 by task syz.1.299/5996 CPU: 0 PID: 5996 Comm: syz.1.299 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026 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+0x1540/0x16a8 fs/erofs/zdata.c:-1 z_erofs_read_folio+0x2dc/0x5cc fs/erofs/zdata.c:1702 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+0x74/0x14c 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 4467: 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] kmem_cache_alloc_node+0x258/0x344 mm/slub.c:3404 __alloc_skb+0x128/0x728 net/core/skbuff.c:505 alloc_skb include/linux/skbuff.h:1303 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] nsim_dev_trap_report_work+0x204/0x94c drivers/net/netdevsim/dev.c:851 process_one_work+0x7e4/0x13bc kernel/workqueue.c:2292 worker_thread+0x8cc/0xfe8 kernel/workqueue.c:2439 kthread+0x254/0x2e0 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Freed by task 4467: 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 kfree_skbmem+0x10c/0x198 net/core/skbuff.c:-1 __kfree_skb net/core/skbuff.c:871 [inline] consume_skb+0xa8/0x104 net/core/skbuff.c:1038 nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline] nsim_dev_trap_report_work+0x618/0x94c drivers/net/netdevsim/dev.c:851 process_one_work+0x7e4/0x13bc kernel/workqueue.c:2292 worker_thread+0x8cc/0xfe8 kernel/workqueue.c:2439 kthread+0x254/0x2e0 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 The buggy address belongs to the object at ffff0000f2757000 which belongs to the cache skbuff_head_cache of size 240 The buggy address is located 0 bytes inside of 240-byte region [ffff0000f2757000, ffff0000f27570f0) The buggy address belongs to the physical page: page:00000000fdb0521d refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x132757 flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000200 0000000000000000 dead000000000122 ffff0000c0870180 raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000f2756f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff0000f2756f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff0000f2757000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000f2757080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc ffff0000f2757100: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ================================================================== syz.1.299: attempt to access beyond end of device loop1: rw=0, sector=34359738360, nr_sectors = 8 limit=16 syz.1.299: attempt to access beyond end of device loop1: rw=0, sector=34359738360, nr_sectors = 8 limit=16 syz.1.299: attempt to access beyond end of device loop1: rw=0, sector=34359738360, nr_sectors = 8 limit=16 syz.1.299: attempt to access beyond end of device loop1: rw=0, sector=34359738360, nr_sectors = 8 limit=16 syz.1.299: attempt to access beyond end of device loop1: rw=0, sector=34359738360, nr_sectors = 8 limit=16 syz.1.299: attempt to access beyond end of device loop1: rw=0, sector=34359738360, nr_sectors = 8 limit=16 syz.1.299: attempt to access beyond end of device loop1: rw=0, sector=34359738360, nr_sectors = 8 limit=16