==================================================================
BUG: KASAN: double-free or invalid-free in security_tun_dev_free_security+0x3e/0x70 security/security.c:2341

CPU: 0 PID: 17287 Comm: syz-executor.2 Not tainted 5.14.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
 print_address_description.constprop.0.cold+0x6c/0x2d6 mm/kasan/report.c:233
 kasan_report_invalid_free+0x51/0x80 mm/kasan/report.c:358
 ____kasan_slab_free mm/kasan/common.c:346 [inline]
 __kasan_slab_free+0xf6/0x110 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 __cache_free mm/slab.c:3445 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3803
 security_tun_dev_free_security+0x3e/0x70 security/security.c:2341
 tun_free_netdev+0xdc/0x140 drivers/net/tun.c:2210
 netdev_run_todo+0x6b4/0xa80 net/core/dev.c:10643
 __tun_chr_ioctl.isra.0+0x9c4/0x4270 drivers/net/tun.c:3297
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl fs/ioctl.c:1055 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665e9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb17442d188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665e9
RDX: 0000000000400030 RSI: 00000000400454ca RDI: 0000000000000003
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 00007ffe0526128f R14: 00007fb17442d300 R15: 0000000000022000

Allocated by task 17287:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 ____kasan_kmalloc mm/kasan/common.c:472 [inline]
 __kasan_kmalloc+0xa1/0xd0 mm/kasan/common.c:522
 kasan_kmalloc include/linux/kasan.h:264 [inline]
 kmem_cache_alloc_trace+0x1e4/0x480 mm/slab.c:3575
 kmalloc include/linux/slab.h:591 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 selinux_tun_dev_alloc_security+0x43/0x180 security/selinux/hooks.c:5607
 security_tun_dev_alloc_security+0x40/0x90 security/security.c:2335
 __tun_chr_ioctl.isra.0+0x2820/0x4270 drivers/net/tun.c:2722
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl fs/ioctl.c:1055 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 17287:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free mm/kasan/common.c:328 [inline]
 __kasan_slab_free+0xd1/0x110 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 __cache_free mm/slab.c:3445 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3803
 security_tun_dev_free_security+0x3e/0x70 security/security.c:2341
 __tun_chr_ioctl.isra.0+0x2d27/0x4270 drivers/net/tun.c:2777
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl fs/ioctl.c:1055 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff888018896940
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff888018896940, ffff888018896960)
The buggy address belongs to the page:
page:ffffea0000622580 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888018896fc1 pfn:0x18896
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea00007e0008 ffffea0000cbcf88 ffff888010840100
raw: ffff888018896fc1 ffff888018896000 0000000100000039 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 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 11028, ts 220648895143, free_ts 220647694716
 prep_new_page mm/page_alloc.c:2436 [inline]
 get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4168
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5390
 __alloc_pages_node include/linux/gfp.h:570 [inline]
 kmem_getpages mm/slab.c:1377 [inline]
 cache_grow_begin+0x75/0x460 mm/slab.c:2593
 cache_alloc_refill+0x27f/0x380 mm/slab.c:2965
 ____cache_alloc mm/slab.c:3048 [inline]
 ____cache_alloc mm/slab.c:3031 [inline]
 __do_cache_alloc mm/slab.c:3275 [inline]
 slab_alloc mm/slab.c:3316 [inline]
 __do_kmalloc mm/slab.c:3700 [inline]
 __kmalloc_track_caller+0x3d3/0x4d0 mm/slab.c:3717
 kstrdup+0x36/0x70 mm/util.c:60
 kstrdup_const+0x53/0x80 mm/util.c:83
 __kernfs_new_node+0x9d/0x8b0 fs/kernfs/dir.c:579
 kernfs_new_node+0x93/0x120 fs/kernfs/dir.c:645
 kernfs_create_link+0xcb/0x230 fs/kernfs/symlink.c:39
 sysfs_do_create_link_sd+0x90/0x140 fs/sysfs/symlink.c:44
 sysfs_do_create_link fs/sysfs/symlink.c:80 [inline]
 sysfs_create_link+0x5f/0xc0 fs/sysfs/symlink.c:92
 device_add_class_symlinks drivers/base/core.c:3095 [inline]
 device_add+0x789/0x2180 drivers/base/core.c:3303
 netdev_register_kobject+0x181/0x430 net/core/net-sysfs.c:1955
 register_netdevice+0xd33/0x1500 net/core/dev.c:10349
 __tun_chr_ioctl.isra.0+0x2c2a/0x4270 drivers/net/tun.c:2746
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1346 [inline]
 free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1397
 free_unref_page_prepare mm/page_alloc.c:3332 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3411
 mm_free_pgd kernel/fork.c:636 [inline]
 __mmdrop+0xcb/0x3f0 kernel/fork.c:687
 mmdrop include/linux/sched/mm.h:49 [inline]
 __mmput+0x3b4/0x470 kernel/fork.c:1111
 mmput+0x58/0x60 kernel/fork.c:1122
 free_bprm+0x65/0x2e0 fs/exec.c:1479
 kernel_execve+0x380/0x460 fs/exec.c:1976
 call_usermodehelper_exec_async+0x2e3/0x580 kernel/umh.c:112
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
 ffff888018896800: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
 ffff888018896880: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff888018896900: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                                           ^
 ffff888018896980: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
 ffff888018896a00: fb fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================