loop1: rw=524288, sector=1056, nr_sectors = 16 limit=16 syz.1.308: attempt to access beyond end of device loop1: rw=524288, 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 ffff0000f2f93000 by task syz.1.308/5693 CPU: 1 PID: 5693 Comm: syz.1.308 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026 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+0x14d4/0x1694 fs/erofs/zdata.c:1597 z_erofs_read_folio+0x2d8/0x5c8 fs/erofs/zdata.c:1687 filemap_read_folio+0x134/0x384 mm/filemap.c:2490 filemap_update_page mm/filemap.c:2575 [inline] filemap_get_pages mm/filemap.c:2689 [inline] filemap_read+0x12cc/0x2104 mm/filemap.c:2759 generic_file_read_iter+0xf8/0x5c4 mm/filemap.c:2941 call_read_iter include/linux/fs.h:2259 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x3d4/0x7f0 fs/read_write.c:470 ksys_read+0x12c/0x224 fs/read_write.c:613 __do_sys_read fs/read_write.c:623 [inline] __se_sys_read fs/read_write.c:621 [inline] __arm64_sys_read+0x7c/0x90 fs/read_write.c:621 __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 4326: 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+0x22c/0x308 mm/slub.c:3383 kmem_cache_zalloc include/linux/slab.h:689 [inline] __proc_create+0x30c/0x700 fs/proc/generic.c:448 proc_create_reg+0x88/0x10c fs/proc/generic.c:575 proc_create_net_single+0xa0/0x164 fs/proc/proc_net.c:213 kcm_proc_init_net+0x5c/0xe8 net/kcm/kcmproc.c:350 ops_init+0x2b0/0x53c net/core/net_namespace.c:138 setup_net+0x474/0xb34 net/core/net_namespace.c:336 copy_net_ns+0x2b8/0x578 net/core/net_namespace.c:508 create_new_namespaces+0x318/0x5ec kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x108/0x158 kernel/nsproxy.c:226 ksys_unshare+0x3e0/0x6dc kernel/fork.c:3282 __do_sys_unshare kernel/fork.c:3353 [inline] __se_sys_unshare kernel/fork.c:3351 [inline] __arm64_sys_unshare+0x3c/0x50 kernel/fork.c:3351 __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 The buggy address belongs to the object at ffff0000f2f93000 which belongs to the cache proc_dir_entry of size 256 The buggy address is located 0 bytes inside of 256-byte region [ffff0000f2f93000, ffff0000f2f93100) The buggy address belongs to the physical page: page:000000005377ed73 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000f2f93000 pfn:0x132f93 flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000200 fffffc0003cc0fc8 fffffc00034e3f88 ffff0000c03dd680 raw: ffff0000f2f93000 00000000000c0002 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000f2f92f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff0000f2f92f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff0000f2f93000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000f2f93080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000f2f93100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ================================================================== syz.1.308: attempt to access beyond end of device loop1: rw=0, sector=1056, nr_sectors = 8 limit=16