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BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:643 [inline]
BUG: KASAN: use-after-free in string+0x20f/0x2a0 lib/vsprintf.c:725
Read of size 1 at addr ffff888109ab4780 by task syz.3.1298/5423

CPU: 1 PID: 5423 Comm: syz.3.1298 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:348
 string_nocheck lib/vsprintf.c:643 [inline]
 string+0x20f/0x2a0 lib/vsprintf.c:725
 vsnprintf+0xec5/0x1990 lib/vsprintf.c:2805
 seq_vprintf fs/seq_file.c:391 [inline]
 seq_printf+0x185/0x280 fs/seq_file.c:406
 show_interrupts+0x8f9/0xa00 kernel/irq/proc.c:527
 traverse+0x215/0x5e0 fs/seq_file.c:111
 seq_lseek+0x13b/0x260 fs/seq_file.c:323
 proc_reg_llseek+0x1c1/0x2a0 fs/proc/inode.c:289
 vfs_llseek fs/read_write.c:289 [inline]
 ksys_lseek fs/read_write.c:302 [inline]
 __do_sys_lseek fs/read_write.c:313 [inline]
 __se_sys_lseek fs/read_write.c:311 [inline]
 __x64_sys_lseek+0x182/0x200 fs/read_write.c:311
 x64_sys_call+0x297/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:9
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f63e939e159
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:00007f63e7df7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000008
RAX: ffffffffffffffda RBX: 00007f63e9626090 RCX: 00007f63e939e159
RDX: 0000000000000000 RSI: 0000002000000008 RDI: 0000000000000007
RBP: 00007f63e943506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f63e9626128 R14: 00007f63e9626090 R15: 00007ffdd96fe4e8
 </TASK>

Allocated by task 3672:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:380 [inline]
 __kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
 kasan_kmalloc include/linux/kasan.h:212 [inline]
 __do_kmalloc_node mm/slab_common.c:938 [inline]
 __kmalloc_node+0xb2/0x1e0 mm/slab_common.c:945
 kmalloc_node include/linux/slab.h:589 [inline]
 __vmalloc_area_node mm/vmalloc.c:3070 [inline]
 __vmalloc_node_range+0x564/0x1440 mm/vmalloc.c:3256
 __vmalloc_node mm/vmalloc.c:3321 [inline]
 vzalloc+0x78/0x90 mm/vmalloc.c:3394
 xt_counters_alloc+0x44/0x50 net/netfilter/x_tables.c:1402
 __do_replace+0xb1/0x950 net/ipv4/netfilter/ip_tables.c:1046
 do_replace net/ipv4/netfilter/ip_tables.c:1141 [inline]
 do_ipt_set_ctl+0xb23/0xdf0 net/ipv4/netfilter/ip_tables.c:1634
 nf_setsockopt+0x284/0x2b0 net/netfilter/nf_sockopt.c:101
 ip_setsockopt+0xed/0x100 net/ipv4/ip_sockglue.c:1468
 tcp_setsockopt+0xeb/0x100 net/ipv4/tcp.c:3860
 sock_common_setsockopt+0xb1/0xc0 net/core/sock.c:3716
 __sys_setsockopt+0x2ff/0x4e0 net/socket.c:2278
 __do_sys_setsockopt net/socket.c:2289 [inline]
 __se_sys_setsockopt net/socket.c:2286 [inline]
 __x64_sys_setsockopt+0xbf/0xd0 net/socket.c:2286
 x64_sys_call+0x124/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:55
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 3672:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
 kasan_slab_free include/linux/kasan.h:178 [inline]
 slab_free_hook mm/slub.c:1750 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
 slab_free mm/slub.c:3712 [inline]
 __kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728
 kfree+0x6f/0xf0 mm/slab_common.c:990
 kvfree+0x35/0x40 mm/util.c:639
 __vunmap+0xb32/0xc00 mm/vmalloc.c:2745
 __vfree mm/vmalloc.c:2788 [inline]
 vfree+0x61/0x90 mm/vmalloc.c:2819
 __do_replace+0x839/0x950 net/ipv4/netfilter/ip_tables.c:1090
 do_replace net/ipv4/netfilter/ip_tables.c:1141 [inline]
 do_ipt_set_ctl+0xb23/0xdf0 net/ipv4/netfilter/ip_tables.c:1634
 nf_setsockopt+0x284/0x2b0 net/netfilter/nf_sockopt.c:101
 ip_setsockopt+0xed/0x100 net/ipv4/ip_sockglue.c:1468
 tcp_setsockopt+0xeb/0x100 net/ipv4/tcp.c:3860
 sock_common_setsockopt+0xb1/0xc0 net/core/sock.c:3716
 __sys_setsockopt+0x2ff/0x4e0 net/socket.c:2278
 __do_sys_setsockopt net/socket.c:2289 [inline]
 __se_sys_setsockopt net/socket.c:2286 [inline]
 __x64_sys_setsockopt+0xbf/0xd0 net/socket.c:2286
 x64_sys_call+0x124/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:55
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff888109ab4780
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes inside of
 8-byte region [ffff888109ab4780, ffff888109ab4788)

The buggy address belongs to the physical page:
page:ffffea000426ad00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109ab4
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 0000000000000000 dead000000000001 ffff888100042300
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, tgid 1 (swapper/0), ts 3589073273, free_ts 0
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2673
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2680
 get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4587
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5931
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3e0 mm/slub.c:2020
 ___slab_alloc+0x70f/0xb70 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 __kmem_cache_alloc_node+0x204/0x2d0 mm/slub.c:3423
 __do_kmalloc_node mm/slab_common.c:937 [inline]
 __kmalloc+0xa4/0x1e0 mm/slab_common.c:951
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 acpi_os_allocate_zeroed include/acpi/platform/aclinuxex.h:57 [inline]
 acpi_ns_internalize_name+0x2cd/0x3b0 drivers/acpi/acpica/nsutils.c:331
 acpi_ns_get_node_unlocked drivers/acpi/acpica/nsutils.c:666 [inline]
 acpi_ns_get_node+0x1a7/0x360 drivers/acpi/acpica/nsutils.c:726
 acpi_get_handle+0x184/0x290 drivers/acpi/acpica/nsxfname.c:98
 acpi_has_method+0x89/0xe0 drivers/acpi/utils.c:591
 acpi_is_ioapic drivers/acpi/ioapic.c:74 [inline]
 handle_ioapic_add+0xaf/0x970 drivers/acpi/ioapic.c:106
 acpi_ns_walk_namespace+0x251/0x680 drivers/acpi/acpica/nswalk.c:-1
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888109ab4680: fc fc fa fc fc fc fc 07 fc fc fc fc fa fc fc fc
 ffff888109ab4700: fc 00 fc fc fc fc 05 fc fc fc fc fa fc fc fc fc
>ffff888109ab4780: fa fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 05
                   ^
 ffff888109ab4800: fc fc fc fc fa fc fc fc fc fa fc fc fc fc fa fc
 ffff888109ab4880: fc fc fc 00 fc fc fc fc 00 fc fc fc fc fa fc fc
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