================================================================== BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:645 [inline] BUG: KASAN: slab-use-after-free in string+0x204/0x290 lib/vsprintf.c:727 Read of size 1 at addr ffff88801f3d0870 by task syz.3.5724/26332 CPU: 1 PID: 26332 Comm: syz.3.5724 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xa8/0x210 mm/kasan/report.c:468 kasan_report+0x117/0x150 mm/kasan/report.c:581 string_nocheck lib/vsprintf.c:645 [inline] string+0x204/0x290 lib/vsprintf.c:727 vsnprintf+0xf72/0x1ba0 lib/vsprintf.c:2823 vprintk_store+0x3d9/0xd50 kernel/printk/printk.c:2226 vprintk_emit+0x117/0x610 kernel/printk/printk.c:2322 _printk+0xde/0x130 kernel/printk/printk.c:2366 __setup_irq+0xf92/0x1f30 kernel/irq/manage.c:1837 request_threaded_irq+0x2c1/0x3a0 kernel/irq/manage.c:2205 request_irq include/linux/interrupt.h:168 [inline] das16m1_attach+0x1cf/0xae0 drivers/comedi/drivers/das16m1.c:527 comedi_device_attach+0x526/0x710 drivers/comedi/drivers.c:1014 do_devconfig_ioctl drivers/comedi/comedi_fops.c:872 [inline] comedi_unlocked_ioctl+0x6c4/0x1170 drivers/comedi/comedi_fops.c:2178 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f312959e159 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:00007f312a403028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f3129825fa0 RCX: 00007f312959e159 RDX: 00002000000003c0 RSI: 0000000040946400 RDI: 0000000000000003 RBP: 00007f312963506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3129826038 R14: 00007f3129825fa0 R15: 00007ffc08491e58 Allocated by task 21534: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:198 [inline] __do_kmalloc_node mm/slab_common.c:1007 [inline] __kmalloc_node+0xb6/0x240 mm/slab_common.c:1014 kmalloc_node include/linux/slab.h:620 [inline] __vmalloc_area_node mm/vmalloc.c:3175 [inline] __vmalloc_node_range+0x598/0x1320 mm/vmalloc.c:3370 __vmalloc_node mm/vmalloc.c:3435 [inline] vzalloc+0x79/0x90 mm/vmalloc.c:3508 __do_replace+0xb4/0x9b0 net/ipv6/netfilter/ip6_tables.c:1061 do_replace net/ipv6/netfilter/ip6_tables.c:1156 [inline] do_ip6t_set_ctl+0xb41/0xe10 net/ipv6/netfilter/ip6_tables.c:1641 nf_setsockopt+0x263/0x280 net/netfilter/nf_sockopt.c:101 do_sock_setsockopt+0x175/0x1a0 net/socket.c:2322 __sys_setsockopt net/socket.c:2345 [inline] __do_sys_setsockopt net/socket.c:2354 [inline] __se_sys_setsockopt net/socket.c:2351 [inline] __x64_sys_setsockopt+0x182/0x200 net/socket.c:2351 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 21534: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843 vfree+0x2b0/0x340 mm/vmalloc.c:2904 __do_replace+0x878/0x9b0 net/ipv6/netfilter/ip6_tables.c:1105 do_replace net/ipv6/netfilter/ip6_tables.c:1156 [inline] do_ip6t_set_ctl+0xb41/0xe10 net/ipv6/netfilter/ip6_tables.c:1641 nf_setsockopt+0x263/0x280 net/netfilter/nf_sockopt.c:101 do_sock_setsockopt+0x175/0x1a0 net/socket.c:2322 __sys_setsockopt net/socket.c:2345 [inline] __do_sys_setsockopt net/socket.c:2354 [inline] __se_sys_setsockopt net/socket.c:2351 [inline] __x64_sys_setsockopt+0x182/0x200 net/socket.c:2351 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff88801f3d0870 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes inside of freed 8-byte region [ffff88801f3d0870, ffff88801f3d0878) The buggy address belongs to the physical page: page:ffffea00007cf400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1f3d0 flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000800 ffff888017c41280 dead000000000100 dead000000000122 raw: 0000000000000000 0000000080660066 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, tgid 1 (swapper/0), ts 7040963954, free_ts 7040428448 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1582 prep_new_page mm/page_alloc.c:1589 [inline] get_page_from_freelist+0x2181/0x22a0 mm/page_alloc.c:3221 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2118 alloc_slab_page+0x5d/0x180 mm/slub.c:1881 allocate_slab mm/slub.c:2028 [inline] new_slab+0x87/0x2d0 mm/slub.c:2081 ___slab_alloc+0xc5c/0x12f0 mm/slub.c:3253 __slab_alloc mm/slub.c:3339 [inline] __slab_alloc_node mm/slub.c:3392 [inline] slab_alloc_node mm/slub.c:3485 [inline] __kmem_cache_alloc_node+0x11f/0x250 mm/slub.c:3534 __do_kmalloc_node mm/slab_common.c:1006 [inline] __kmalloc_node_track_caller+0xa4/0x230 mm/slab_common.c:1027 kstrdup+0x3b/0x80 mm/util.c:62 __kernfs_new_node+0xaa/0x7f0 fs/kernfs/dir.c:620 kernfs_new_node+0x14c/0x260 fs/kernfs/dir.c:700 kernfs_create_link+0xa7/0x200 fs/kernfs/symlink.c:39 sysfs_do_create_link_sd+0x83/0x110 fs/sysfs/symlink.c:44 device_add_class_symlinks+0x1cf/0x240 drivers/base/core.c:3444 device_add+0x4f9/0xc40 drivers/base/core.c:3636 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1182 [inline] free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459 mm_free_pgd kernel/fork.c:811 [inline] __mmdrop+0xb4/0x3d0 kernel/fork.c:927 free_bprm+0x144/0x390 fs/exec.c:1514 kernel_execve+0x3e9/0x980 fs/exec.c:2060 call_usermodehelper_exec_async+0x20b/0x350 kernel/umh.c:110 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Memory state around the buggy address: ffff88801f3d0700: fc 06 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc ffff88801f3d0780: 04 fc fc fc fc fa fc fc fc fc 00 fc fc fc fc 00 >ffff88801f3d0800: fc fc fc fc 00 fc fc fc fc fa fc fc fc fc fa fc ^ ffff88801f3d0880: fc fc fc 05 fc fc fc fc 05 fc fc fc fc fa fc fc ffff88801f3d0900: fc fc 05 fc fc fc fc 07 fc fc fc fc 05 fc fc fc ==================================================================