loop1: rw=0, sector=8, nr_sectors = 16 limit=16 syz.1.55: attempt to access beyond end of device loop1: rw=0, sector=8, nr_sectors = 16 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+0x3a4/0x490 fs/erofs/decompressor.c:346 Read of size 4096 at addr ffff0000c3f5f000 by task syz.1.55/4694 CPU: 1 PID: 4694 Comm: syz.1.55 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+0x1564/0x16cc fs/erofs/zdata.c:-1 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 el1_abort+0x3c/0x5c arch/arm64/kernel/entry-common.c:367 el1h_64_sync_handler+0x50/0xac arch/arm64/kernel/entry-common.c:427 el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:580 do_strncpy_from_user lib/strncpy_from_user.c:41 [inline] strncpy_from_user+0x25c/0x578 lib/strncpy_from_user.c:139 getname_flags+0xec/0x45c fs/namei.c:150 getname+0x28/0x38 fs/namei.c:218 do_sys_openat2+0xdc/0x3f4 fs/open.c:1314 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+0x98/0x2b4 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 Allocated by task 4417: 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] kmalloc_trace+0x7c/0x94 mm/slab_common.c:1031 kmalloc include/linux/slab.h:563 [inline] gro_cells_destroy+0x2d0/0x384 net/core/gro_cells.c:125 ip_tunnel_dev_free+0x20/0x60 net/ipv4/ip_tunnel.c:1044 netdev_run_todo+0xb50/0xd2c net/core/dev.c:10552 rtnl_unlock+0x14/0x20 net/core/rtnetlink.c:147 ip_tunnel_delete_nets+0x2d4/0x32c net/ipv4/ip_tunnel.c:1158 vti_exit_batch_net+0x30/0x54 net/ipv4/ip_vti.c:515 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x650/0xa84 net/core/net_namespace.c:640 process_one_work+0x7f8/0x13a4 kernel/workqueue.c:2292 worker_thread+0x8c4/0xfec kernel/workqueue.c:2439 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Last potentially related work creation: kasan_save_stack+0x40/0x70 mm/kasan/common.c:46 __kasan_record_aux_stack+0xc0/0xdc mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496 call_rcu+0x100/0x94c kernel/rcu/tree.c:2849 gro_cells_destroy+0x318/0x384 net/core/gro_cells.c:128 ip_tunnel_dev_free+0x20/0x60 net/ipv4/ip_tunnel.c:1044 netdev_run_todo+0xb50/0xd2c net/core/dev.c:10552 rtnl_unlock+0x14/0x20 net/core/rtnetlink.c:147 ip_tunnel_delete_nets+0x2d4/0x32c net/ipv4/ip_tunnel.c:1158 vti_exit_batch_net+0x30/0x54 net/ipv4/ip_vti.c:515 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x650/0xa84 net/core/net_namespace.c:640 process_one_work+0x7f8/0x13a4 kernel/workqueue.c:2292 worker_thread+0x8c4/0xfec kernel/workqueue.c:2439 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 The buggy address belongs to the object at ffff0000c3f5f000 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 0 bytes inside of 128-byte region [ffff0000c3f5f000, ffff0000c3f5f080) The buggy address belongs to the physical page: page:00000000c2a770b0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000c3f5f100 pfn:0x103f5f flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000200 fffffc00036f34c8 fffffc0003438188 ffff0000c0002300 raw: ffff0000c3f5f100 000000000010000b 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000c3f5ef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff0000c3f5ef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff0000c3f5f000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000c3f5f080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000c3f5f100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Zero length message leads to an empty skb