================================================================== BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline] BUG: KASAN: slab-use-after-free in string+0x216/0x2d0 lib/vsprintf.c:730 Read of size 1 at addr ffff88802a362758 by task syz.3.4205/20757 CPU: 0 UID: 0 PID: 20757 Comm: syz.3.4205 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 string_nocheck lib/vsprintf.c:648 [inline] string+0x216/0x2d0 lib/vsprintf.c:730 vsnprintf+0x74a/0xef0 lib/vsprintf.c:2949 seq_vprintf fs/seq_file.c:392 [inline] seq_printf+0x188/0x290 fs/seq_file.c:407 input_devices_seq_show+0x10f/0x640 drivers/input/input.c:1178 seq_read_iter+0x8d5/0xca0 fs/seq_file.c:273 seq_read+0x367/0x480 fs/seq_file.c:163 pde_read fs/proc/inode.c:308 [inline] proc_reg_read+0x1e9/0x2e0 fs/proc/inode.c:320 vfs_read+0x213/0xa80 fs/read_write.c:572 ksys_read+0x150/0x270 fs/read_write.c:716 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f241839e0d9 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:00007f241924c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f2418626090 RCX: 00007f241839e0d9 RDX: 0000000000002020 RSI: 0000200000000300 RDI: 0000000000000009 RBP: 00007f2418435024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2418626128 R14: 00007f2418626090 R15: 00007ffe3bd2b458 Allocated by task 20404: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5414 [inline] __kmalloc_node_noprof+0x4b9/0x720 mm/slub.c:5426 _kmalloc_node_noprof include/linux/slab.h:1200 [inline] qdisc_alloc+0x92/0x9d0 net/sched/sch_generic.c:998 qdisc_create_dflt+0x8e/0x4e0 net/sched/sch_generic.c:1053 attach_one_default_qdisc net/sched/sch_generic.c:1219 [inline] netdev_for_each_tx_queue include/linux/netdevice.h:2749 [inline] attach_default_qdiscs net/sched/sch_generic.c:1237 [inline] dev_activate+0x37a/0x1150 net/sched/sch_generic.c:1296 __dev_open+0x699/0x850 net/core/dev.c:1733 __dev_change_flags+0x329/0x820 net/core/dev.c:9812 netif_change_flags+0x7c/0x1b0 net/core/dev.c:9877 dev_change_flags+0x128/0x260 net/core/dev_api.c:68 devinet_ioctl+0x966/0x1c50 net/ipv4/devinet.c:1199 inet_ioctl+0x42a/0x560 net/ipv4/af_inet.c:1009 sock_do_ioctl+0x101/0x320 net/socket.c:1325 sock_ioctl+0x57a/0x7e0 net/socket.c:1446 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 16: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/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:6499 [inline] kfree+0x1c5/0x650 mm/slub.c:6792 rcu_do_batch kernel/rcu/tree.c:2650 [inline] rcu_core+0x926/0x1260 kernel/rcu/tree.c:2919 handle_softirqs+0x226/0x860 kernel/softirq.c:645 __do_softirq kernel/softirq.c:679 [inline] invoke_softirq kernel/softirq.c:519 [inline] __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767 irq_exit_rcu+0x9/0x30 kernel/softirq.c:784 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3181 [inline] call_rcu+0xee/0x8b0 kernel/rcu/tree.c:3301 qdisc_put net/sched/sch_generic.c:1150 [inline] dev_shutdown+0x352/0x450 net/sched/sch_generic.c:1515 unregister_netdevice_many_notify+0x11f4/0x2140 net/core/dev.c:12504 unregister_netdevice_many net/core/dev.c:12588 [inline] unregister_netdevice_queue+0x2f5/0x340 net/core/dev.c:12389 unregister_netdevice include/linux/netdevice.h:3487 [inline] __tun_detach+0x1074/0x1900 drivers/net/tun.c:637 tun_detach drivers/net/tun.c:653 [inline] tun_chr_close+0x10a/0x1c0 drivers/net/tun.c:3587 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x73a/0x2360 kernel/exit.c:1008 do_group_exit+0x22d/0x2f0 kernel/exit.c:1151 get_signal+0x121b/0x12c0 kernel/signal.c:3039 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802a362000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1880 bytes inside of freed 2048-byte region [ffff88802a362000, ffff88802a362800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802a362000 pfn:0x2a360 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 ffff88813ff16000 ffffea0000c9e610 ffffea0001dd5810 raw: ffff88802a362000 0000000000080005 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88813ff16000 ffffea0000c9e610 ffffea0001dd5810 head: ffff88802a362000 0000000000080005 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 1, tgid 1 (swapper/0), ts 13388551888 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab+0x7d/0x620 mm/slub.c:3462 new_slab mm/slub.c:3513 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7410 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __kmalloc_cache_noprof+0x39b/0x600 mm/slub.c:5559 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] usb_add_gadget+0x57/0x700 drivers/usb/gadget/udc/core.c:1415 usb_add_gadget_udc_release+0x19c/0x1f0 drivers/usb/gadget/udc/core.c:1517 dummy_udc_probe+0x6b1/0x7b0 drivers/usb/gadget/udc/dummy_hcd.c:1121 platform_probe+0xf9/0x190 drivers/base/platform.c:1507 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x254/0xae0 drivers/base/dd.c:706 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898 __device_attach_driver+0x270/0x410 drivers/base/dd.c:1026 bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500 page_owner free stack trace missing Memory state around the buggy address: ffff88802a362600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802a362680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802a362700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802a362780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802a362800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================