================================================================== BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:641 [inline] BUG: KASAN: use-after-free in string+0x20f/0x2a0 lib/vsprintf.c:723 Read of size 1 at addr ffff8881045d5398 by task syz.9.5116/19867 CPU: 0 PID: 19867 Comm: syz.9.5116 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0x100/0x140 mm/kasan/report.c:452 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306 string_nocheck lib/vsprintf.c:641 [inline] string+0x20f/0x2a0 lib/vsprintf.c:723 vsnprintf+0xec5/0x1990 lib/vsprintf.c:2689 seq_vprintf fs/seq_file.c:398 [inline] seq_printf+0x185/0x280 fs/seq_file.c:413 show_interrupts+0x921/0xa90 kernel/irq/proc.c:526 traverse+0x1f2/0x590 fs/seq_file.c:111 seq_lseek+0x13b/0x260 fs/seq_file.c:323 pde_lseek fs/proc/inode.c:283 [inline] proc_reg_llseek+0x1d6/0x2b0 fs/proc/inode.c:294 vfs_llseek fs/read_write.c:300 [inline] ksys_lseek fs/read_write.c:313 [inline] __do_sys_lseek fs/read_write.c:324 [inline] __se_sys_lseek fs/read_write.c:322 [inline] __x64_sys_lseek+0x181/0x200 fs/read_write.c:322 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f9392afd1d9 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:00007f9391556028 EFLAGS: 00000246 ORIG_RAX: 0000000000000008 RAX: ffffffffffffffda RBX: 00007f9392d84fa0 RCX: 00007f9392afd1d9 RDX: 0000000000000000 RSI: 0000002000000008 RDI: 0000000000000005 RBP: 00007f9392b94888 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9392d85038 R14: 00007f9392d84fa0 R15: 00007ffc440adf28 Allocated by task 18594: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] ____kasan_kmalloc mm/kasan/common.c:509 [inline] __kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] __kmalloc+0x19f/0x330 mm/slub.c:4038 __kmalloc_node include/linux/slab.h:421 [inline] kmalloc_node include/linux/slab.h:578 [inline] __vmalloc_area_node mm/vmalloc.c:2520 [inline] __vmalloc_node_range+0x294/0x7a0 mm/vmalloc.c:2629 __vmalloc_node mm/vmalloc.c:2689 [inline] vzalloc+0x78/0x90 mm/vmalloc.c:2742 xt_counters_alloc+0x44/0x50 net/netfilter/x_tables.c:1367 __do_replace+0xa8/0x9f0 net/ipv6/netfilter/ip6_tables.c:1063 do_replace net/ipv6/netfilter/ip6_tables.c:1158 [inline] do_ip6t_set_ctl+0xa98/0xd80 net/ipv6/netfilter/ip6_tables.c:1643 nf_setsockopt+0x272/0x2a0 net/netfilter/nf_sockopt.c:101 ipv6_setsockopt+0x2568/0x36f0 net/ipv6/ipv6_sockglue.c:1014 tcp_setsockopt+0x22b/0x1d80 net/ipv4/tcp.c:3500 sock_common_setsockopt+0xa0/0xb0 net/core/sock.c:3326 __sys_setsockopt+0x2fa/0x480 net/socket.c:2147 __do_sys_setsockopt net/socket.c:2158 [inline] __se_sys_setsockopt net/socket.c:2155 [inline] __x64_sys_setsockopt+0xbf/0xd0 net/socket.c:2155 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 19604: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370 kasan_slab_free include/linux/kasan.h:220 [inline] slab_free_hook mm/slub.c:1600 [inline] slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626 slab_free mm/slub.c:3208 [inline] kfree+0xc0/0x270 mm/slub.c:4196 ovl_free_fs+0x560/0x6e0 fs/overlayfs/super.c:255 ovl_fill_super+0x3357/0x3f50 fs/overlayfs/super.c:2074 mount_nodev+0x5c/0xf0 fs/super.c:1499 ovl_mount+0x2c/0x40 fs/overlayfs/super.c:2082 legacy_get_tree+0xed/0x190 fs/fs_context.c:593 vfs_get_tree+0x89/0x260 fs/super.c:1583 do_new_mount+0x25a/0xa30 fs/namespace.c:3006 path_mount+0x581/0xca0 fs/namespace.c:3336 do_mount fs/namespace.c:3349 [inline] __do_sys_mount fs/namespace.c:3557 [inline] __se_sys_mount+0x320/0x390 fs/namespace.c:3534 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3534 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff8881045d5398 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes inside of 8-byte region [ffff8881045d5398, ffff8881045d53a0) The buggy address belongs to the page: page:ffffea0004117540 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1045d5 flags: 0x4000000000000200(slab) raw: 4000000000000200 ffffea00047b1d40 0000001200000012 ffff888100043c80 raw: 0000000000000000 0000000000660066 00000001ffffffff 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, ts 2553221097, free_ts 0 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x176/0x190 mm/page_alloc.c:2462 get_page_from_freelist+0x225f/0x23f0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x29a/0x640 mm/page_alloc.c:5384 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1813 [inline] new_slab+0x84/0x3f0 mm/slub.c:1874 new_slab_objects mm/slub.c:2632 [inline] ___slab_alloc+0x2f8/0x4c0 mm/slub.c:2796 __slab_alloc+0x63/0xa0 mm/slub.c:2836 slab_alloc_node mm/slub.c:2918 [inline] slab_alloc mm/slub.c:2960 [inline] __kmalloc_track_caller+0x1e4/0x310 mm/slub.c:4541 kstrdup mm/util.c:63 [inline] kstrdup_const+0x55/0x90 mm/util.c:86 kvasprintf_const+0xd7/0x240 lib/kasprintf.c:-1 kobject_set_name_vargs+0x61/0x110 lib/kobject.c:297 kobject_add_varg lib/kobject.c:392 [inline] kobject_init_and_add+0xeb/0x190 lib/kobject.c:481 sysfs_slab_add+0x89/0x2a0 mm/slub.c:5610 slab_sysfs_init+0x61/0x15e mm/slub.c:5695 do_one_initcall+0x205/0x5e0 init/main.c:1172 do_initcall_level+0x174/0x2dc init/main.c:1245 do_initcalls+0x50/0x92 init/main.c:1261 page_owner free stack trace missing Memory state around the buggy address: ffff8881045d5280: 00 fc fc fc fc fa fc fc fc fc 00 fc fc fc fc fa ffff8881045d5300: fc fc fc fc 00 fc fc fc fc fa fc fc fc fc fa fc >ffff8881045d5380: fc fc fc fa fc fc fc fc fa fc fc fc fc 00 fc fc ^ ffff8881045d5400: fc fc fa fc fc fc fc 00 fc fc fc fc fa fc fc fc ffff8881045d5480: fc fa fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc ==================================================================