loop0: detected capacity change from 0 to 16 erofs: (device loop0): mounted with root inode @ nid 36. erofs: (device loop0): z_erofs_readahead: readahead error at page 4 @ nid 89 syz.0.1: attempt to access beyond end of device loop0: rw=524288, sector=34359736328, nr_sectors = 16 limit=16 syz.0.1: attempt to access beyond end of device loop0: rw=524288, sector=8, nr_sectors = 16 limit=16 ================================================================== BUG: KASAN: slab-out-of-bounds in memcpy_to_page include/linux/highmem.h:403 [inline] BUG: KASAN: slab-out-of-bounds in z_erofs_transform_plain+0x3a4/0x490 fs/erofs/decompressor.c:346 Read of size 4096 at addr ffff0000d4bc1000 by task syz.0.1/4414 CPU: 0 PID: 4414 Comm: syz.0.1 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_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 4377: 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] kzalloc include/linux/slab.h:699 [inline] ref_tracker_alloc+0x138/0x3f0 lib/ref_tracker.c:85 __netdev_tracker_alloc include/linux/netdevice.h:4049 [inline] netdev_hold include/linux/netdevice.h:4078 [inline] ___neigh_create+0xc50/0x2400 net/core/neighbour.c:658 __neigh_create+0x44/0x58 net/core/neighbour.c:738 ip6_finish_output2+0x1678/0x1840 net/ipv6/ip6_output.c:129 __ip6_finish_output net/ipv6/ip6_output.c:205 [inline] ip6_finish_output+0x594/0x92c net/ipv6/ip6_output.c:216 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x274/0x500 net/ipv6/ip6_output.c:237 dst_output include/net/dst.h:453 [inline] NF_HOOK+0x15c/0x444 include/linux/netfilter.h:302 mld_sendpack+0x88c/0x10ec net/ipv6/mcast.c:1825 mld_send_cr net/ipv6/mcast.c:2126 [inline] mld_ifc_work+0x768/0xa88 net/ipv6/mcast.c:2658 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 ffff0000d4bc1000 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 0 bytes inside of 128-byte region [ffff0000d4bc1000, ffff0000d4bc1080) The buggy address belongs to the physical page: page:000000001c4768f9 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x114bc1 flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000200 0000000000000000 dead000000000122 ffff0000c0002300 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000d4bc0f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff0000d4bc0f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff0000d4bc1000: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff0000d4bc1080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000d4bc1100: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== syz.0.1: attempt to access beyond end of device loop0: rw=0, sector=34359736328, nr_sectors = 8 limit=16 syz.0.1: attempt to access beyond end of device loop0: rw=0, sector=34359736328, nr_sectors = 8 limit=16