================================================================== BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline] BUG: KASAN: slab-use-after-free in string+0x216/0x2d0 lib/vsprintf.c:730 Read of size 1 at addr ffff888028836620 by task syz.6.4688/16640 CPU: 0 UID: 0 PID: 16640 Comm: syz.6.4688 Tainted: G L Y syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP, [Y]=FORCED_BIND Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 string_nocheck lib/vsprintf.c:648 [inline] string+0x216/0x2d0 lib/vsprintf.c:730 vsnprintf+0x74a/0xef0 lib/vsprintf.c:2946 seq_vprintf fs/seq_file.c:392 [inline] seq_printf+0x188/0x290 fs/seq_file.c:407 irq_seq_show+0x5f3/0x860 kernel/irq/proc.c:601 seq_read_iter+0x463/0xca0 fs/seq_file.c:231 proc_reg_read_iter+0x1b7/0x280 fs/proc/inode.c:299 do_iter_readv_writev+0x612/0x8c0 fs/read_write.c:-1 vfs_readv+0x28d/0x850 fs/read_write.c:1729 do_preadv fs/read_write.c:1843 [inline] __do_sys_preadv fs/read_write.c:1890 [inline] __se_sys_preadv fs/read_write.c:1885 [inline] __x64_sys_preadv+0x19c/0x2b0 fs/read_write.c:1885 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4100f9e1d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4101df8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007f4101225fa0 RCX: 00007f4100f9e1d9 RDX: 0000000000000001 RSI: 0000200000004d00 RDI: 0000000000000003 RBP: 00007f4101035888 R08: 0000000080000002 R09: 0000000000000000 R10: 0000000000000074 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4101226038 R14: 00007f4101225fa0 R15: 00007fff00939ab8 Allocated by task 14553: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:409 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5531 [inline] __kmalloc_node_noprof+0x4b4/0x720 mm/slub.c:5543 _kmalloc_node_noprof include/linux/slab.h:1200 [inline] __vmalloc_area_node mm/vmalloc.c:3943 [inline] __vmalloc_node_range_noprof+0x5d1/0x16f0 mm/vmalloc.c:4165 __vmalloc_node_noprof mm/vmalloc.c:4226 [inline] vzalloc_noprof+0xb2/0xe0 mm/vmalloc.c:4304 alloc_counters net/ipv4/netfilter/arp_tables.c:671 [inline] copy_entries_to_user net/ipv4/netfilter/arp_tables.c:692 [inline] get_entries net/ipv4/netfilter/arp_tables.c:787 [inline] do_arpt_get_ctl+0x915/0x1270 net/ipv4/netfilter/arp_tables.c:1013 nf_getsockopt+0x26e/0x290 net/netfilter/nf_sockopt.c:116 ip_getsockopt+0x19e/0x230 net/ipv4/ip_sockglue.c:1785 do_sock_getsockopt+0x4aa/0x640 net/socket.c:2505 __sys_getsockopt net/socket.c:2536 [inline] __do_sys_getsockopt net/socket.c:2543 [inline] __se_sys_getsockopt net/socket.c:2540 [inline] __x64_sys_getsockopt+0x1a4/0x240 net/socket.c:2540 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 14553: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:264 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2780 [inline] slab_free mm/slub.c:6630 [inline] kfree+0x1c5/0x650 mm/slub.c:6923 vfree+0x426/0x490 mm/vmalloc.c:3561 copy_entries_to_user net/ipv4/netfilter/arp_tables.c:722 [inline] get_entries net/ipv4/netfilter/arp_tables.c:787 [inline] do_arpt_get_ctl+0x104e/0x1270 net/ipv4/netfilter/arp_tables.c:1013 nf_getsockopt+0x26e/0x290 net/netfilter/nf_sockopt.c:116 ip_getsockopt+0x19e/0x230 net/ipv4/ip_sockglue.c:1785 do_sock_getsockopt+0x4aa/0x640 net/socket.c:2505 __sys_getsockopt net/socket.c:2536 [inline] __do_sys_getsockopt net/socket.c:2543 [inline] __se_sys_getsockopt net/socket.c:2540 [inline] __x64_sys_getsockopt+0x1a4/0x240 net/socket.c:2540 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888028836620 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes inside of freed 8-byte region [ffff888028836620, ffff888028836628) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28836 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88813ff22500 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000800080 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 6697005024 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1854 prep_new_page mm/page_alloc.c:1862 [inline] get_page_from_freelist+0x220f/0x2280 mm/page_alloc.c:3933 __alloc_frozen_pages_noprof+0x1fc/0x400 mm/page_alloc.c:5477 alloc_slab_page mm/slub.c:3384 [inline] allocate_slab+0x7d/0x5e0 mm/slub.c:3499 new_slab mm/slub.c:3550 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7539 refill_sheaf mm/slub.c:2917 [inline] __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4811 alloc_from_pcs mm/slub.c:4887 [inline] slab_alloc_node mm/slub.c:5021 [inline] __do_kmalloc_node mm/slub.c:5530 [inline] __kmalloc_node_track_caller_noprof+0x543/0x720 mm/slub.c:5662 __kmemdup_nul mm/util.c:64 [inline] kstrdup+0x42/0x100 mm/util.c:84 kobject_set_name_vargs+0x61/0x110 lib/kobject.c:274 dev_set_name+0xe2/0x140 drivers/base/core.c:3564 tty_register_device_attr+0x3b6/0x9b0 drivers/tty/tty_io.c:3248 tty_register_device drivers/tty/tty_io.c:3189 [inline] tty_register_driver+0x868/0xe50 drivers/tty/tty_io.c:3469 legacy_pty_init+0x3b2/0x5d0 drivers/tty/pty.c:576 pty_init+0x9/0x20 drivers/tty/pty.c:916 do_one_initcall+0x250/0x870 init/main.c:1360 do_initcall_level+0x10a/0x1a0 init/main.c:1422 page_owner free stack trace missing Memory state around the buggy address: ffff888028836500: 05 fc fc fc 05 fc fc fc 05 fc fc fc 05 fc fc fc ffff888028836580: 05 fc fc fc 05 fc fc fc 05 fc fc fc 05 fc fc fc >ffff888028836600: 05 fc fc fc fa fc fc fc 05 fc fc fc fa fc fc fc ^ ffff888028836680: 00 fc fc fc 05 fc fc fc 00 fc fc fc fa fc fc fc ffff888028836700: fa fc fc fc 04 fc fc fc 00 fc fc fc 00 fc fc fc ==================================================================