audit: type=1400 audit(1563785144.910:36): avc: denied { map } for pid=7219 comm="syz-executor652" path="/root/syz-executor652679038" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 ================================================================== BUG: KASAN: use-after-free in debugfs_remove /fs/debugfs/inode.c:662 [inline] BUG: KASAN: use-after-free in debugfs_remove+0xfb/0x120 /fs/debugfs/inode.c:654 Read of size 8 at addr ffff88809475e640 by task kworker/1:2/2505 CPU: 1 PID: 2505 Comm: kworker/1:2 Not tainted 4.14.134 #29 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events __blk_release_queue Call Trace: __dump_stack /lib/dump_stack.c:17 [inline] dump_stack+0x138/0x19c /lib/dump_stack.c:53 print_address_description.cold+0x7c/0x1dc /mm/kasan/report.c:252 kasan_report_error /mm/kasan/report.c:351 [inline] kasan_report /mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2af /mm/kasan/report.c:393 __asan_report_load8_noabort+0x14/0x20 /mm/kasan/report.c:430 debugfs_remove /fs/debugfs/inode.c:662 [inline] debugfs_remove+0xfb/0x120 /fs/debugfs/inode.c:654 blk_trace_free+0x38/0x140 /kernel/trace/blktrace.c:324 blk_trace_cleanup /kernel/trace/blktrace.c:351 [inline] blk_trace_remove+0x59/0x80 /kernel/trace/blktrace.c:364 blk_trace_shutdown+0x4f/0x60 /kernel/trace/blktrace.c:728 __blk_release_queue+0x1f3/0x480 /block/blk-sysfs.c:827 process_one_work+0x863/0x1600 /kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 /kernel/workqueue.c:2248 kthread+0x319/0x430 /kernel/kthread.c:232 ret_from_fork+0x24/0x30 /arch/x86/entry/entry_64.S:404 Allocated by task 7239: save_stack_trace+0x16/0x20 /arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 /mm/kasan/kasan.c:447 set_track /mm/kasan/kasan.c:459 [inline] kasan_kmalloc /mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 /mm/kasan/kasan.c:529 kasan_slab_alloc+0xf/0x20 /mm/kasan/kasan.c:489 kmem_cache_alloc+0x12e/0x780 /mm/slab.c:3552 __d_alloc+0x2d/0x9f0 /fs/dcache.c:1623 d_alloc+0x4d/0x270 /fs/dcache.c:1710 __lookup_hash /fs/namei.c:1570 [inline] __lookup_hash+0x58/0x180 /fs/namei.c:1562 lookup_one_len+0x27b/0x3a0 /fs/namei.c:2538 start_creating /fs/debugfs/inode.c:314 [inline] start_creating+0xa6/0x1b0 /fs/debugfs/inode.c:290 __debugfs_create_file+0x53/0x3d0 /fs/debugfs/inode.c:353 debugfs_create_file+0x5a/0x70 /fs/debugfs/inode.c:404 do_blk_trace_setup+0x32d/0xb10 /kernel/trace/blktrace.c:529 blk_trace_setup+0xbd/0x140 /kernel/trace/blktrace.c:579 kobject: 'queue' (ffff8880a0b8c298): kobject_add_internal: parent: 'loop0', set: '' blk_trace_ioctl+0x147/0x270 /kernel/trace/blktrace.c:694 blkdev_ioctl+0x100/0x1860 /block/ioctl.c:580 block_ioctl+0xde/0x120 /fs/block_dev.c:1881 vfs_ioctl /fs/ioctl.c:46 [inline] file_ioctl /fs/ioctl.c:500 [inline] do_vfs_ioctl+0x7ae/0x1060 /fs/ioctl.c:684 SYSC_ioctl /fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 /fs/ioctl.c:692 kobject: 'mq' (ffff8880a0b8c2d8): kobject_add_internal: parent: 'loop0', set: '' do_syscall_64+0x1e8/0x640 /arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 kobject: 'mq' (ffff8880a0b8c2d8): kobject_uevent_env Freed by task 17: save_stack_trace+0x16/0x20 /arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 /mm/kasan/kasan.c:447 set_track /mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 /mm/kasan/kasan.c:524 kobject: 'mq' (ffff8880a0b8c2d8): kobject_uevent_env: filter function caused the event to drop! __cache_free /mm/slab.c:3496 [inline] kmem_cache_free+0x83/0x2b0 /mm/slab.c:3758 __d_free+0x20/0x30 /fs/dcache.c:270 __rcu_reclaim /kernel/rcu/rcu.h:195 [inline] rcu_do_batch /kernel/rcu/tree.c:2699 [inline] invoke_rcu_callbacks /kernel/rcu/tree.c:2962 [inline] __rcu_process_callbacks /kernel/rcu/tree.c:2929 [inline] rcu_process_callbacks+0x7b8/0x12b0 /kernel/rcu/tree.c:2946 __do_softirq+0x244/0x9a0 /kernel/softirq.c:288 kobject: '0' (ffff8880994a98e8): kobject_add_internal: parent: 'mq', set: '' The buggy address belongs to the object at ffff88809475e600 which belongs to the cache dentry of size 288 The buggy address is located 64 bytes inside of 288-byte region [ffff88809475e600, ffff88809475e720) The buggy address belongs to the page: page:ffffea000251d780 count:1 mapcount:0 mapping:ffff88809475e080 index:0xffff88809475ece0 kobject: 'cpu0' (ffffe8ffffc2d318): kobject_add_internal: parent: '0', set: '' flags: 0x1fffc0000000100(slab) raw: 01fffc0000000100 ffff88809475e080 ffff88809475ece0 0000000100000004 raw: ffffea000251d420 ffffea0002516a20 ffff88821f8b5680 0000000000000000 page dumped because: kasan: bad access detected kobject: 'cpu1' (ffffe8ffffd2d318): kobject_add_internal: parent: '0', set: '' Memory state around the buggy address: ffff88809475e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809475e580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff88809475e600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809475e680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb kobject: 'queue' (ffff8880a0b8c298): kobject_uevent_env ffff88809475e700: fb fb fb fb fc fc fc fc fc fc fc fc fb fb fb fb ==================================================================