================================================================== 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+0xa09/0xb50 fs/kernfs/dir.c:1369 Read of size 2 at addr ffff88802296ce30 by task syz-executor215/3830 CPU: 1 PID: 3830 Comm: syz-executor215 Not tainted 6.0.0-rc3-next-20220901-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 kernfs_type include/linux/kernfs.h:335 [inline] kernfs_leftmost_descendant fs/kernfs/dir.c:1261 [inline] __kernfs_remove+0xa09/0xb50 fs/kernfs/dir.c:1369 kernfs_remove_by_name_ns+0xa8/0x110 fs/kernfs/dir.c:1589 sysfs_slab_add+0x13e/0x1e0 mm/slub.c:5833 __kmem_cache_create+0x542/0x6d0 mm/slub.c:4827 create_cache mm/slab_common.c:229 [inline] kmem_cache_create_usercopy+0x1f9/0x300 mm/slab_common.c:335 p9_client_create+0xca5/0x1070 net/9p/client.c:993 v9fs_session_init+0x1e2/0x1810 fs/9p/v9fs.c:408 v9fs_mount+0xba/0xc90 fs/9p/vfs_super.c:126 legacy_get_tree+0x105/0x220 fs/fs_context.c:610 vfs_get_tree+0x89/0x2f0 fs/super.c:1530 do_new_mount fs/namespace.c:3040 [inline] path_mount+0x1326/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 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+0x63/0xcd RIP: 0033:0x7fcb4f826f59 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 00 00 90 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe9e3053c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007ffe9e305400 RCX: 00007fcb4f826f59 RDX: 00000000200001c0 RSI: 0000000020000040 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000020000300 R09: 000000000000b8c4 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000f4240 R13: 000000000000b8c4 R14: 00007ffe9e3053ec R15: 00007ffe9e3053f0 Allocated by task 3829: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:437 [inline] __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:470 kasan_slab_alloc include/linux/kasan.h:224 [inline] slab_post_alloc_hook mm/slab.h:737 [inline] slab_alloc_node mm/slub.c:3317 [inline] slab_alloc mm/slub.c:3325 [inline] __kmem_cache_alloc_lru mm/slub.c:3332 [inline] kmem_cache_alloc+0x2b7/0x3d0 mm/slub.c:3341 kmem_cache_zalloc include/linux/slab.h:685 [inline] __kernfs_new_node+0xd4/0x8b0 fs/kernfs/dir.c:593 kernfs_new_node fs/kernfs/dir.c:655 [inline] kernfs_create_dir_ns+0x9c/0x220 fs/kernfs/dir.c:1010 sysfs_create_dir_ns+0x127/0x290 fs/sysfs/dir.c:59 create_dir lib/kobject.c:63 [inline] kobject_add_internal+0x2c9/0x8f0 lib/kobject.c:223 kobject_add_varg lib/kobject.c:358 [inline] kobject_init_and_add+0x101/0x160 lib/kobject.c:441 sysfs_slab_add+0x161/0x1e0 mm/slub.c:5844 __kmem_cache_create+0x542/0x6d0 mm/slub.c:4827 create_cache mm/slab_common.c:229 [inline] kmem_cache_create_usercopy+0x1f9/0x300 mm/slab_common.c:335 p9_client_create+0xca5/0x1070 net/9p/client.c:993 v9fs_session_init+0x1e2/0x1810 fs/9p/v9fs.c:408 v9fs_mount+0xba/0xc90 fs/9p/vfs_super.c:126 legacy_get_tree+0x105/0x220 fs/fs_context.c:610 vfs_get_tree+0x89/0x2f0 fs/super.c:1530 do_new_mount fs/namespace.c:3040 [inline] path_mount+0x1326/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 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+0x63/0xcd Freed by task 3830: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:367 [inline] ____kasan_slab_free+0x166/0x1c0 mm/kasan/common.c:329 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1651 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1677 slab_free mm/slub.c:3580 [inline] kmem_cache_free+0xe7/0x5b0 mm/slub.c:3602 kernfs_put.part.0+0x2c4/0x540 fs/kernfs/dir.c:547 kernfs_put+0x42/0x50 fs/kernfs/dir.c:521 __kernfs_remove+0x7a6/0xb50 fs/kernfs/dir.c:1407 kernfs_remove_by_name_ns+0xa8/0x110 fs/kernfs/dir.c:1589 sysfs_slab_add+0x13e/0x1e0 mm/slub.c:5833 __kmem_cache_create+0x542/0x6d0 mm/slub.c:4827 create_cache mm/slab_common.c:229 [inline] kmem_cache_create_usercopy+0x1f9/0x300 mm/slab_common.c:335 p9_client_create+0xca5/0x1070 net/9p/client.c:993 v9fs_session_init+0x1e2/0x1810 fs/9p/v9fs.c:408 v9fs_mount+0xba/0xc90 fs/9p/vfs_super.c:126 legacy_get_tree+0x105/0x220 fs/fs_context.c:610 vfs_get_tree+0x89/0x2f0 fs/super.c:1530 do_new_mount fs/namespace.c:3040 [inline] path_mount+0x1326/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 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+0x63/0xcd The buggy address belongs to the object at ffff88802296cd98 which belongs to the cache kernfs_node_cache of size 168 The buggy address is located 152 bytes inside of 168-byte region [ffff88802296cd98, ffff88802296ce40) The buggy address belongs to the physical page: page:ffffea00008a5b00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2296c flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea00005c36c0 dead000000000003 ffff8880119d4c80 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 3698, tgid 3698 (syz-executor215), ts 44262431932, free_ts 44258443593 prep_new_page mm/page_alloc.c:2534 [inline] get_page_from_freelist+0x109b/0x2ce0 mm/page_alloc.c:4284 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5542 alloc_pages+0x1a6/0x270 mm/mempolicy.c:2280 alloc_slab_page mm/slub.c:1721 [inline] allocate_slab+0x228/0x370 mm/slub.c:1866 new_slab mm/slub.c:1919 [inline] ___slab_alloc+0xad0/0x1440 mm/slub.c:3100 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3198 slab_alloc_node mm/slub.c:3283 [inline] slab_alloc mm/slub.c:3325 [inline] __kmem_cache_alloc_lru mm/slub.c:3332 [inline] kmem_cache_alloc+0x31c/0x3d0 mm/slub.c:3341 kmem_cache_zalloc include/linux/slab.h:685 [inline] __kernfs_new_node+0xd4/0x8b0 fs/kernfs/dir.c:593 kernfs_new_node+0x93/0x120 fs/kernfs/dir.c:655 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:3259 [inline] device_add+0x700/0x1e90 drivers/base/core.c:3465 device_create_groups_vargs+0x203/0x280 drivers/base/core.c:4194 device_create+0xdf/0x120 drivers/base/core.c:4236 bdi_register_va.part.0+0x9c/0x800 mm/backing-dev.c:869 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1451 [inline] free_pcp_prepare+0x5e4/0xd20 mm/page_alloc.c:1501 free_unref_page_prepare mm/page_alloc.c:3382 [inline] free_unref_page+0x19/0x4d0 mm/page_alloc.c:3478 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2514 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:447 kasan_slab_alloc include/linux/kasan.h:224 [inline] slab_post_alloc_hook mm/slab.h:737 [inline] slab_alloc_node mm/slub.c:3317 [inline] slab_alloc mm/slub.c:3325 [inline] __kmem_cache_alloc_lru mm/slub.c:3332 [inline] kmem_cache_alloc+0x2b7/0x3d0 mm/slub.c:3341 getname_flags.part.0+0x50/0x4f0 fs/namei.c:139 getname_flags include/linux/audit.h:320 [inline] getname+0x8e/0xd0 fs/namei.c:218 do_sys_openat2+0xf5/0x4c0 fs/open.c:1302 do_sys_open fs/open.c:1324 [inline] __do_sys_openat fs/open.c:1340 [inline] __se_sys_openat fs/open.c:1335 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1335 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+0x63/0xcd Memory state around the buggy address: ffff88802296cd00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff88802296cd80: fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802296ce00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88802296ce80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802296cf00: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc ==================================================================