================================================================== 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 ffff888027f00ac0 by task syz.6.4897/24087 CPU: 0 UID: 0 PID: 24087 Comm: syz.6.4897 Tainted: G L N syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP, [N]=TEST Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 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:2945 vprintk_store+0x3b0/0xbe0 kernel/printk/printk.c:2307 vprintk_emit+0x139/0x6b0 kernel/printk/printk.c:2455 _printk+0xcf/0x110 kernel/printk/printk.c:2504 __setup_irq.cold+0x3be/0x3f1 kernel/irq/manage.c:1820 request_threaded_irq+0x261/0x3e0 kernel/irq/manage.c:2183 request_irq include/linux/interrupt.h:176 [inline] pcl812_attach+0x1b62/0x2300 drivers/comedi/drivers/pcl812.c:1174 comedi_device_attach+0x40e/0x6b0 drivers/comedi/drivers.c:1101 do_devconfig_ioctl+0x1b3/0x6d0 drivers/comedi/comedi_fops.c:930 comedi_unlocked_ioctl+0x860/0x3310 drivers/comedi/comedi_fops.c:2302 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f53b639e0d9 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:00007f53b71b5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f53b6625fa0 RCX: 00007f53b639e0d9 RDX: 0000200000000240 RSI: 0000000040946400 RDI: 0000000000000004 RBP: 00007f53b6435024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f53b6626038 R14: 00007f53b6625fa0 R15: 00007ffc422ad768 Allocated by task 17801: 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] __do_kmalloc_node mm/slub.c:5334 [inline] __kmalloc_node_noprof+0x339/0x830 mm/slub.c:5346 _kmalloc_node_noprof include/linux/slab.h:1197 [inline] __vmalloc_area_node mm/vmalloc.c:3893 [inline] __vmalloc_node_range_noprof+0x409/0x1630 mm/vmalloc.c:4104 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4165 alloc_counters net/ipv4/netfilter/ip_tables.c:799 [inline] copy_entries_to_user net/ipv4/netfilter/ip_tables.c:821 [inline] get_entries net/ipv4/netfilter/ip_tables.c:1020 [inline] do_ipt_get_ctl+0x7e0/0xbf0 net/ipv4/netfilter/ip_tables.c:1669 nf_getsockopt+0x7c/0xe0 net/netfilter/nf_sockopt.c:116 ip_getsockopt+0x192/0x1e0 net/ipv4/ip_sockglue.c:1777 tcp_getsockopt+0xa1/0x110 net/ipv4/tcp.c:4864 do_sock_getsockopt+0x50a/0x6e0 net/socket.c:2474 __sys_getsockopt+0x148/0x260 net/socket.c:2505 __do_sys_getsockopt net/socket.c:2512 [inline] __se_sys_getsockopt net/socket.c:2509 [inline] __x64_sys_getsockopt+0xbd/0x160 net/socket.c:2509 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 17801: 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:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x22b/0x6c0 mm/slub.c:6692 vfree mm/vmalloc.c:3511 [inline] vfree+0x12e/0x750 mm/vmalloc.c:3484 copy_entries_to_user net/ipv4/netfilter/ip_tables.c:864 [inline] get_entries net/ipv4/netfilter/ip_tables.c:1020 [inline] do_ipt_get_ctl+0x9d7/0xbf0 net/ipv4/netfilter/ip_tables.c:1669 nf_getsockopt+0x7c/0xe0 net/netfilter/nf_sockopt.c:116 ip_getsockopt+0x192/0x1e0 net/ipv4/ip_sockglue.c:1777 tcp_getsockopt+0xa1/0x110 net/ipv4/tcp.c:4864 do_sock_getsockopt+0x50a/0x6e0 net/socket.c:2474 __sys_getsockopt+0x148/0x260 net/socket.c:2505 __do_sys_getsockopt net/socket.c:2512 [inline] __se_sys_getsockopt net/socket.c:2509 [inline] __x64_sys_getsockopt+0xbd/0x160 net/socket.c:2509 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888027f00ac0 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes inside of freed 8-byte region [ffff888027f00ac0, ffff888027f00ac8) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888027f00700 pfn:0x27f00 flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000200 ffff88801bc42500 ffffea0000a9be50 ffffea0000aa3a90 raw: ffff888027f00700 0000000800800063 00000000f5000000 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 6548406337, free_ts 6548109285 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3266 [inline] allocate_slab mm/slub.c:3380 [inline] new_slab+0xa2/0x640 mm/slub.c:3426 refill_objects+0xe3/0x410 mm/slub.c:7310 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675 alloc_from_pcs mm/slub.c:4773 [inline] slab_alloc_node mm/slub.c:4905 [inline] __do_kmalloc_node mm/slub.c:5333 [inline] __kmalloc_node_track_caller_noprof+0x679/0x830 mm/slub.c:5471 __kmemdup_nul mm/util.c:64 [inline] kstrdup+0x51/0xe0 mm/util.c:84 kstrdup_const+0x63/0x80 mm/util.c:104 kvasprintf_const+0x10f/0x1a0 lib/kasprintf.c:48 kobject_set_name_vargs+0x5a/0x140 lib/kobject.c:274 dev_set_name+0xc7/0x100 drivers/base/core.c:3560 tty_register_device_attr+0x2fb/0x7f0 drivers/tty/tty_io.c:3255 tty_register_device drivers/tty/tty_io.c:3196 [inline] tty_register_driver+0x769/0xb50 drivers/tty/tty_io.c:3474 legacy_pty_init drivers/tty/pty.c:579 [inline] pty_init+0x65d/0xdc0 drivers/tty/pty.c:919 do_one_initcall+0x11d/0x700 init/main.c:1347 page last free pid 120 tgid 120 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline] __kasan_populate_vmalloc+0x1ea/0x210 mm/kasan/shadow.c:424 kasan_populate_vmalloc include/linux/kasan.h:580 [inline] alloc_vmap_area+0x95d/0x2bb0 mm/vmalloc.c:2145 __get_vm_area_node+0x1ca/0x330 mm/vmalloc.c:3248 __vmalloc_node_range_noprof+0x228/0x1630 mm/vmalloc.c:4064 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4165 alloc_thread_stack_node kernel/fork.c:359 [inline] dup_task_struct kernel/fork.c:929 [inline] copy_process+0x7fb/0x8030 kernel/fork.c:2115 kernel_clone+0x176/0x9d0 kernel/fork.c:2748 user_mode_thread+0xcc/0x110 kernel/fork.c:2824 call_usermodehelper_exec_work kernel/umh.c:171 [inline] call_usermodehelper_exec_work+0xcb/0x180 kernel/umh.c:157 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888027f00980: 00 fc fc fc 02 fc fc fc 05 fc fc fc 02 fc fc fc ffff888027f00a00: 06 fc fc fc 02 fc fc fc 05 fc fc fc 06 fc fc fc >ffff888027f00a80: 05 fc fc fc 02 fc fc fc fa fc fc fc 02 fc fc fc ^ ffff888027f00b00: fa fc fc fc fa fc fc fc 06 fc fc fc fa fc fc fc ffff888027f00b80: fa fc fc fc fa fc fc fc 04 fc fc fc 00 fc fc fc ==================================================================