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BUG: KASAN: use-after-free in kernfs_type include/linux/kernfs.h:335 [inline]
BUG: KASAN: use-after-free in kernfs_leftmost_descendant fs/kernfs/dir.c:1261 [inline]
BUG: KASAN: use-after-free in __kernfs_remove+0xf2d/0x1180 fs/kernfs/dir.c:1369
Read of size 2 at addr ffff888079d53f18 by task syz-executor.4/4006

CPU: 0 PID: 4006 Comm: syz-executor.4 Not tainted 6.0.0-syzkaller-06475-g4c86114194e6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description+0x65/0x4b0 mm/kasan/report.c:317
 print_report+0x108/0x220 mm/kasan/report.c:433
 kasan_report+0xfb/0x130 mm/kasan/report.c:495
 kernfs_type include/linux/kernfs.h:335 [inline]
 kernfs_leftmost_descendant fs/kernfs/dir.c:1261 [inline]
 __kernfs_remove+0xf2d/0x1180 fs/kernfs/dir.c:1369
 kernfs_remove_by_name_ns+0x96/0xe0 fs/kernfs/dir.c:1589
 sysfs_slab_add+0x54/0x2a0 mm/slub.c:5955
 __kmem_cache_create+0x34/0x170 mm/slub.c:4906
 create_cache mm/slab_common.c:229 [inline]
 kmem_cache_create_usercopy+0x1a6/0x340 mm/slab_common.c:335
 p9_client_create+0xbbe/0x1030 net/9p/client.c:993
 v9fs_session_init+0x1e3/0x1990 fs/9p/v9fs.c:408
 v9fs_mount+0xd2/0xcb0 fs/9p/vfs_super.c:126
 legacy_get_tree+0xea/0x180 fs/fs_context.c:610
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x289/0xad0 fs/namespace.c:3040
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fac37e8a5a9
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fac38f38168 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fac37fabf80 RCX: 00007fac37e8a5a9
RDX: 0000000020000140 RSI: 0000000020000200 RDI: 0000000000000000
RBP: 00007fac37ee5580 R08: 0000000020000580 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffee12433af R14: 00007fac38f38300 R15: 0000000000022000
 </TASK>

Allocated by task 3970:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:437 [inline]
 __kasan_slab_alloc+0xb2/0xe0 mm/kasan/common.c:470
 kasan_slab_alloc include/linux/kasan.h:224 [inline]
 slab_post_alloc_hook mm/slab.h:727 [inline]
 slab_alloc_node mm/slub.c:3248 [inline]
 slab_alloc mm/slub.c:3256 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3263 [inline]
 kmem_cache_alloc+0x1a6/0x310 mm/slub.c:3273
 kmem_cache_zalloc include/linux/slab.h:723 [inline]
 __kernfs_new_node+0xdb/0x730 fs/kernfs/dir.c:593
 kernfs_new_node fs/kernfs/dir.c:655 [inline]
 kernfs_create_dir_ns+0x90/0x220 fs/kernfs/dir.c:1010
 sysfs_create_dir_ns+0x181/0x390 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:63 [inline]
 kobject_add_internal+0x6dd/0xd10 lib/kobject.c:223
 kobject_add_varg lib/kobject.c:358 [inline]
 kobject_init_and_add+0x123/0x190 lib/kobject.c:441
 sysfs_slab_add+0x80/0x2a0 mm/slub.c:5968
 __kmem_cache_create+0x34/0x170 mm/slub.c:4906
 create_cache mm/slab_common.c:229 [inline]
 kmem_cache_create_usercopy+0x1a6/0x340 mm/slab_common.c:335
 p9_client_create+0xbbe/0x1030 net/9p/client.c:993
 v9fs_session_init+0x1e3/0x1990 fs/9p/v9fs.c:408
 v9fs_mount+0xd2/0xcb0 fs/9p/vfs_super.c:126
 legacy_get_tree+0xea/0x180 fs/fs_context.c:610
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x289/0xad0 fs/namespace.c:3040
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 4006:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4c/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:367
 kasan_slab_free include/linux/kasan.h:200 [inline]
 slab_free_hook mm/slub.c:1759 [inline]
 slab_free_freelist_hook+0x12e/0x1a0 mm/slub.c:1785
 slab_free mm/slub.c:3539 [inline]
 kmem_cache_free+0x95/0x1d0 mm/slub.c:3556
 kernfs_put+0x340/0x490 fs/kernfs/dir.c:547
 __kernfs_remove+0xec0/0x1180 fs/kernfs/dir.c:1407
 kernfs_remove_by_name_ns+0x96/0xe0 fs/kernfs/dir.c:1589
 sysfs_slab_add+0x54/0x2a0 mm/slub.c:5955
 __kmem_cache_create+0x34/0x170 mm/slub.c:4906
 create_cache mm/slab_common.c:229 [inline]
 kmem_cache_create_usercopy+0x1a6/0x340 mm/slab_common.c:335
 p9_client_create+0xbbe/0x1030 net/9p/client.c:993
 v9fs_session_init+0x1e3/0x1990 fs/9p/v9fs.c:408
 v9fs_mount+0xd2/0xcb0 fs/9p/vfs_super.c:126
 legacy_get_tree+0xea/0x180 fs/fs_context.c:610
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x289/0xad0 fs/namespace.c:3040
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888079d53e80
 which belongs to the cache kernfs_node_cache of size 168
The buggy address is located 152 bytes inside of
 168-byte region [ffff888079d53e80, ffff888079d53f28)

The buggy address belongs to the physical page:
page:ffffea0001e754c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x79d53
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888140004c80
raw: 0000000000000000 0000000000110011 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 3916, tgid 3901 (syz-executor.5), ts 199738648345, free_ts 199696754222
 prep_new_page mm/page_alloc.c:2532 [inline]
 get_page_from_freelist+0x72b/0x7a0 mm/page_alloc.c:4283
 __alloc_pages+0x259/0x560 mm/page_alloc.c:5549
 alloc_slab_page+0x70/0xf0 mm/slub.c:1829
 allocate_slab+0x5e/0x520 mm/slub.c:1974
 new_slab mm/slub.c:2034 [inline]
 ___slab_alloc+0x42e/0xce0 mm/slub.c:3036
 __slab_alloc mm/slub.c:3123 [inline]
 slab_alloc_node mm/slub.c:3214 [inline]
 slab_alloc mm/slub.c:3256 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3263 [inline]
 kmem_cache_alloc+0x25d/0x310 mm/slub.c:3273
 kmem_cache_zalloc include/linux/slab.h:723 [inline]
 __kernfs_new_node+0xdb/0x730 fs/kernfs/dir.c:593
 kernfs_new_node fs/kernfs/dir.c:655 [inline]
 kernfs_create_dir_ns+0x90/0x220 fs/kernfs/dir.c:1010
 sysfs_create_dir_ns+0x181/0x390 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:63 [inline]
 kobject_add_internal+0x6dd/0xd10 lib/kobject.c:223
 kset_register lib/kobject.c:846 [inline]
 kset_create_and_add+0x201/0x280 lib/kobject.c:983
 register_queue_kobjects net/core/net-sysfs.c:1766 [inline]
 netdev_register_kobject+0x1a2/0x310 net/core/net-sysfs.c:2019
 register_netdevice+0x136c/0x1a20 net/core/dev.c:10053
 register_netdev+0x37/0x50 net/core/dev.c:10179
 ip6gre_init_net+0x20f/0x2e0 net/ipv6/ip6_gre.c:1638
 ops_init+0x313/0x430 net/core/net_namespace.c:134
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1449 [inline]
 free_pcp_prepare+0x812/0x900 mm/page_alloc.c:1499
 free_unref_page_prepare mm/page_alloc.c:3380 [inline]
 free_unref_page+0x7d/0x630 mm/page_alloc.c:3476
 qlist_free_all+0x2b/0x70 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x169/0x180 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:447
 kasan_slab_alloc include/linux/kasan.h:224 [inline]
 slab_post_alloc_hook mm/slab.h:727 [inline]
 slab_alloc_node mm/slub.c:3248 [inline]
 slab_alloc mm/slub.c:3256 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3263 [inline]
 kmem_cache_alloc+0x1a6/0x310 mm/slub.c:3273
 getname_flags+0xb8/0x4e0 fs/namei.c:139
 user_path_at_empty+0x2a/0x1a0 fs/namei.c:2875
 do_readlinkat+0x11b/0x3b0 fs/stat.c:468
 __do_sys_readlink fs/stat.c:501 [inline]
 __se_sys_readlink fs/stat.c:498 [inline]
 __x64_sys_readlink+0x7b/0x90 fs/stat.c:498
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff888079d53e00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff888079d53e80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888079d53f00: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
                            ^
 ffff888079d53f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888079d54000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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