================================================================== BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline] BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730 Read of size 1 at addr ffff8880226ac758 by task syz.0.3275/12816 CPU: 0 UID: 0 PID: 12816 Comm: syz.0.3275 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 string_nocheck lib/vsprintf.c:648 [inline] string+0x471/0x4d0 lib/vsprintf.c:730 vsnprintf+0x422/0x1300 lib/vsprintf.c:2949 seq_vprintf fs/seq_file.c:392 [inline] seq_printf+0x1a4/0x250 fs/seq_file.c:407 input_devices_seq_show+0x1bf/0x1130 drivers/input/input.c:1178 seq_read_iter+0xbce/0x1270 fs/seq_file.c:273 seq_read+0x344/0x4d0 fs/seq_file.c:163 pde_read fs/proc/inode.c:308 [inline] proc_reg_read+0x240/0x330 fs/proc/inode.c:320 vfs_read+0x1e4/0xb40 fs/read_write.c:572 ksys_read+0x12a/0x250 fs/read_write.c:716 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe1ac59e159 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:00007fe1ad457028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fe1ac825fa0 RCX: 00007fe1ac59e159 RDX: 0000000000002020 RSI: 00002000000028c0 RDI: 0000000000000003 RBP: 00007fe1ac63506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe1ac826038 R14: 00007fe1ac825fa0 R15: 00007ffe892a2518 Allocated by task 4958: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x2f8/0x6d0 mm/slub.c:5563 _kmalloc_noprof include/linux/slab.h:991 [inline] syslog_print+0xf8/0x620 kernel/printk/printk.c:1585 do_syslog+0x5bd/0x6d0 kernel/printk/printk.c:1763 __do_sys_syslog kernel/printk/printk.c:1855 [inline] __se_sys_syslog kernel/printk/printk.c:1853 [inline] __x64_sys_syslog+0x74/0xb0 kernel/printk/printk.c:1853 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 4958: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6508 [inline] kfree+0x22b/0x6d0 mm/slub.c:6801 syslog_print+0x548/0x620 kernel/printk/printk.c:1677 do_syslog+0x5bd/0x6d0 kernel/printk/printk.c:1763 __do_sys_syslog kernel/printk/printk.c:1855 [inline] __se_sys_syslog kernel/printk/printk.c:1853 [inline] __x64_sys_syslog+0x74/0xb0 kernel/printk/printk.c:1853 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880226ac000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1880 bytes inside of freed 2048-byte region [ffff8880226ac000, ffff8880226ac800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880226ad000 pfn:0x226a8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801c034000 ffffea0001f7ea10 ffffea0000c46410 raw: ffff8880226ad000 0000000000080006 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801c034000 ffffea0001f7ea10 ffffea0000c46410 head: ffff8880226ad000 0000000000080006 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5651, tgid 5651 (syz-executor), ts 61705060368 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab mm/slub.c:3462 [inline] new_slab+0xa9/0x6e0 mm/slub.c:3513 refill_objects+0xe3/0x410 mm/slub.c:7417 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x67c/0x840 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] sk_prot_alloc+0x10b/0x2a0 net/core/sock.c:2252 sk_alloc+0x36/0xe80 net/core/sock.c:2308 __netlink_create+0x5e/0x2c0 net/netlink/af_netlink.c:627 netlink_create+0x29b/0x610 net/netlink/af_netlink.c:685 __sock_create+0x339/0x860 net/socket.c:1676 sock_create net/socket.c:1734 [inline] __sys_socket_create net/socket.c:1771 [inline] __sys_socket+0x14d/0x260 net/socket.c:1818 __do_sys_socket net/socket.c:1832 [inline] __se_sys_socket net/socket.c:1830 [inline] __x64_sys_socket+0x72/0xb0 net/socket.c:1830 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 5651 tgid 5651 ts 61536627629 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_lru_noprof+0x265/0x6a0 mm/slub.c:5029 __d_alloc+0x35/0xa50 fs/dcache.c:1907 d_alloc+0x4a/0x1e0 fs/dcache.c:1986 lookup_one_qstr_excl+0x171/0x250 fs/namei.c:1806 __start_dirop fs/namei.c:2920 [inline] start_dirop+0x59/0xb0 fs/namei.c:2942 simple_start_creating+0xf9/0x110 fs/libfs.c:2308 debugfs_start_creating.part.0+0x9f/0x180 fs/debugfs/inode.c:397 debugfs_start_creating fs/debugfs/inode.c:368 [inline] __debugfs_create_file+0x86/0x4d0 fs/debugfs/inode.c:431 debugfs_create_file_unsafe+0x3c/0x50 fs/debugfs/inode.c:512 debugfs_create_mode_unsafe fs/debugfs/file.c:576 [inline] debugfs_create_bool+0x70/0xa0 fs/debugfs/file.c:1012 nsim_fib_debugfs_init drivers/net/netdevsim/fib.c:1535 [inline] nsim_fib_create+0x852/0xc20 drivers/net/netdevsim/fib.c:1600 nsim_drv_probe+0xc15/0x1350 drivers/net/netdevsim/dev.c:1634 Memory state around the buggy address: ffff8880226ac600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880226ac680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880226ac700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880226ac780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880226ac800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================