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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 ffff888109d82258 by task syz.7.1475/6678

CPU: 0 PID: 6678 Comm: syz.7.1475 Tainted: G        W          syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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
 seq_read_iter+0x992/0xd80 fs/seq_file.c:272
 proc_reg_read_iter+0x1e0/0x2b0 fs/proc/inode.c:305
 call_read_iter include/linux/fs.h:2276 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x46e/0x930 fs/read_write.c:470
 ksys_read+0x14a/0x260 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x7b/0x90 fs/read_write.c:621
 x64_sys_call+0x2f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:1
 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: 0033:0x7efc0fd9e159
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:00007efc10bdc028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007efc10026180 RCX: 00007efc0fd9e159
RDX: 0000000000002020 RSI: 0000200000000340 RDI: 0000000000000003
RBP: 00007efc0fe3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efc10026218 R14: 00007efc10026180 R15: 00007ffc2c4e5af8
 </TASK>

Allocated by task 6507:
 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_track_caller+0xb1/0x1e0 mm/slab_common.c:958
 __do_krealloc mm/slab_common.c:1341 [inline]
 krealloc+0x6f/0x110 mm/slab_common.c:1374
 push_jmp_history kernel/bpf/verifier.c:2462 [inline]
 is_state_visited kernel/bpf/verifier.c:12321 [inline]
 do_check+0x2dcd/0xf140 kernel/bpf/verifier.c:12461
 do_check_common+0x11c3/0x1970 kernel/bpf/verifier.c:14940
 do_check_main kernel/bpf/verifier.c:15003 [inline]
 bpf_check+0xa04e/0x10e90 kernel/bpf/verifier.c:15580
 bpf_prog_load+0x10f4/0x1670 kernel/bpf/syscall.c:2624
 __sys_bpf+0x57b/0x850 kernel/bpf/syscall.c:5006
 __do_sys_bpf kernel/bpf/syscall.c:5110 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5108 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5108
 x64_sys_call+0x488/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:322
 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 6507:
 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
 krealloc+0xdc/0x110 mm/slab_common.c:-1
 push_jmp_history kernel/bpf/verifier.c:2462 [inline]
 is_state_visited kernel/bpf/verifier.c:12321 [inline]
 do_check+0x2dcd/0xf140 kernel/bpf/verifier.c:12461
 do_check_common+0x11c3/0x1970 kernel/bpf/verifier.c:14940
 do_check_main kernel/bpf/verifier.c:15003 [inline]
 bpf_check+0xa04e/0x10e90 kernel/bpf/verifier.c:15580
 bpf_prog_load+0x10f4/0x1670 kernel/bpf/syscall.c:2624
 __sys_bpf+0x57b/0x850 kernel/bpf/syscall.c:5006
 __do_sys_bpf kernel/bpf/syscall.c:5110 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5108 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5108
 x64_sys_call+0x488/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:322
 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 ffff888109d82258
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes inside of
 8-byte region [ffff888109d82258, ffff888109d82260)

The buggy address belongs to the physical page:
page:ffffea0004276080 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888109d82528 pfn:0x109d82
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 ffffea000456a708 ffffea000492e088 ffff888100042300
raw: ffff888109d82528 0000000000660064 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 20, tgid 20 (cpuhp/0), ts 2068013066, 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_node_track_caller+0xa1/0x1e0 mm/slab_common.c:958
 kstrdup mm/util.c:66 [inline]
 kstrdup_const+0x5a/0xa0 mm/util.c:89
 __kernfs_new_node+0xa6/0x670 fs/kernfs/dir.c:610
 kernfs_new_node+0x150/0x260 fs/kernfs/dir.c:690
 kernfs_create_link+0xa4/0x200 fs/kernfs/symlink.c:39
 sysfs_do_create_link_sd+0x8a/0x110 fs/sysfs/symlink.c:44
 sysfs_do_create_link fs/sysfs/symlink.c:80 [inline]
 sysfs_create_link+0x68/0x80 fs/sysfs/symlink.c:92
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888109d82100: fc fc fc 05 fc fc fc fc fa fc fc fc fc fa fc fc
 ffff888109d82180: fc fc 05 fc fc fc fc fa fc fc fc fc 00 fc fc fc
>ffff888109d82200: fc fa fc fc fc fc 05 fc fc fc fc fa fc fc fc fc
                                                    ^
 ffff888109d82280: 04 fc fc fc fc 00 fc fc fc fc fa fc fc fc fc 06
 ffff888109d82300: fc fc fc fc 00 fc fc fc fc fa fc fc fc fc 06 fc
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