================================================================== 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 ffff888109a7ae60 by task syz.3.3996/13818 CPU: 0 PID: 13818 Comm: syz.3.3996 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: __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_read_iter+0xc68/0xd80 fs/seq_file.c:195 proc_reg_read_iter+0x1e0/0x2b0 fs/proc/inode.c:305 do_iter_readv_writev fs/read_write.c:-1 [inline] do_iter_read+0x64b/0xb30 fs/read_write.c:796 vfs_readv fs/read_write.c:916 [inline] do_preadv+0x233/0x390 fs/read_write.c:1008 __do_sys_preadv fs/read_write.c:1058 [inline] __se_sys_preadv fs/read_write.c:1053 [inline] __x64_sys_preadv+0x9e/0xb0 fs/read_write.c:1053 x64_sys_call+0x370/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:296 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: 0033:0x7f8f7d19f559 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:00007f8f7e08f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007f8f7d425fa0 RCX: 00007f8f7d19f559 RDX: 0000000000000001 RSI: 00002000000001c0 RDI: 0000000000000008 RBP: 00007f8f7d236b20 R08: 0000000000000004 R09: 0000000000000000 R10: 000000000000ffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8f7d426038 R14: 00007f8f7d425fa0 R15: 00007ffdf7b73ed8 Allocated by task 13086: 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 alloc_counters+0x66/0x520 net/ipv4/netfilter/ip_tables.c:801 copy_entries_to_user net/ipv4/netfilter/ip_tables.c:823 [inline] get_entries net/ipv4/netfilter/ip_tables.c:1022 [inline] do_ipt_get_ctl+0xa7d/0x1190 net/ipv4/netfilter/ip_tables.c:1667 nf_getsockopt+0x27f/0x2a0 net/netfilter/nf_sockopt.c:116 ip_getsockopt+0x157/0x1e0 net/ipv4/ip_sockglue.c:1826 tcp_getsockopt+0xff/0x130 net/ipv4/tcp.c:4464 sock_common_getsockopt+0xaa/0xc0 net/core/sock.c:3696 __sys_getsockopt+0x215/0x490 net/socket.c:2322 __do_sys_getsockopt net/socket.c:2337 [inline] __se_sys_getsockopt net/socket.c:2334 [inline] __x64_sys_getsockopt+0xbf/0xd0 net/socket.c:2334 x64_sys_call+0x3d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:56 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 13086: 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 copy_entries_to_user net/ipv4/netfilter/ip_tables.c:866 [inline] get_entries net/ipv4/netfilter/ip_tables.c:1022 [inline] do_ipt_get_ctl+0xe78/0x1190 net/ipv4/netfilter/ip_tables.c:1667 nf_getsockopt+0x27f/0x2a0 net/netfilter/nf_sockopt.c:116 ip_getsockopt+0x157/0x1e0 net/ipv4/ip_sockglue.c:1826 tcp_getsockopt+0xff/0x130 net/ipv4/tcp.c:4464 sock_common_getsockopt+0xaa/0xc0 net/core/sock.c:3696 __sys_getsockopt+0x215/0x490 net/socket.c:2322 __do_sys_getsockopt net/socket.c:2337 [inline] __se_sys_getsockopt net/socket.c:2334 [inline] __x64_sys_getsockopt+0xbf/0xd0 net/socket.c:2334 x64_sys_call+0x3d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:56 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 ffff888109a7ae60 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes inside of 8-byte region [ffff888109a7ae60, ffff888109a7ae68) The buggy address belongs to the physical page: page:ffffea0004269e80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109a7a flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 dead000000000100 dead000000000122 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 1968696339, 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: ffff888109a7ad00: fc fc fc fc 03 fc fc fc fc fa fc fc fc fc 00 fc ffff888109a7ad80: fc fc fc 00 fc fc fc fc 06 fc fc fc fc 00 fc fc >ffff888109a7ae00: fc fc 00 fc fc fc fc 06 fc fc fc fc fa fc fc fc ^ ffff888109a7ae80: fc 06 fc fc fc fc fa fc fc fc fc fa fc fc fc fc ffff888109a7af00: 06 fc fc fc fc 03 fc fc fc fc 06 fc fc fc fc fa ==================================================================