audit: type=1400 audit(1543719123.816:36): avc: denied { map } for pid=6234 comm="syz-executor433" path="/root/syz-executor433688548" 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+0x10b/0x130 fs/debugfs/inode.c:682 Read of size 8 at addr ffff8881a8c2f340 by task kworker/1:1/22 CPU: 1 PID: 22 Comm: kworker/1:1 Not tainted 4.20.0-rc4+ #138 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:77 [inline] dump_stack+0x244/0x39d lib/dump_stack.c:113 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 debugfs_remove+0x10b/0x130 fs/debugfs/inode.c:682 blk_trace_free+0x35/0x130 kernel/trace/blktrace.c:312 blk_trace_cleanup kernel/trace/blktrace.c:339 [inline] __blk_trace_remove+0x7a/0xa0 kernel/trace/blktrace.c:352 blk_trace_shutdown+0x63/0x80 kernel/trace/blktrace.c:752 __blk_release_queue+0x235/0x510 block/blk-sysfs.c:865 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 kobject: 'mq' (000000000fefe66e): kobject_uevent_env kobject: 'mq' (000000000fefe66e): kobject_uevent_env: filter function caused the event to drop! kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 kobject: '0' (0000000065eae01a): kobject_add_internal: parent: 'mq', set: '' Allocated by task 6237: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 kobject: 'cpu0' (0000000067ae1398): kobject_add_internal: parent: '0', set: '' set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554 __d_alloc+0xc8/0xb90 fs/dcache.c:1599 kobject: 'cpu1' (00000000110970b5): kobject_add_internal: parent: '0', set: '' d_alloc+0x96/0x380 fs/dcache.c:1678 d_alloc_parallel+0x15a/0x1f40 fs/dcache.c:2421 __lookup_slow+0x1e6/0x540 fs/namei.c:1654 lookup_one_len+0x1d8/0x220 fs/namei.c:2543 start_creating+0xc6/0x200 fs/debugfs/inode.c:308 __debugfs_create_file+0x63/0x400 fs/debugfs/inode.c:347 kobject: 'queue' (00000000b6ee61e3): kobject_uevent_env debugfs_create_file+0x57/0x70 fs/debugfs/inode.c:399 do_blk_trace_setup+0x45d/0xdb0 kernel/trace/blktrace.c:528 __blk_trace_setup+0xd5/0x180 kernel/trace/blktrace.c:577 blk_trace_ioctl+0x17a/0x2f0 kernel/trace/blktrace.c:716 blkdev_ioctl+0x9e9/0x21b0 block/ioctl.c:591 block_ioctl+0xee/0x130 fs/block_dev.c:1883 kobject: 'queue' (00000000b6ee61e3): kobject_uevent_env: filter function caused the event to drop! vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 kobject: 'iosched' (000000008cb9c9e2): kobject_add_internal: parent: 'queue', set: '' entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 0: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kobject: 'iosched' (000000008cb9c9e2): kobject_uevent_env kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kmem_cache_free+0x83/0x290 mm/slab.c:3760 __d_free+0x20/0x30 fs/dcache.c:257 __rcu_reclaim kernel/rcu/rcu.h:240 [inline] rcu_do_batch kernel/rcu/tree.c:2437 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2716 [inline] rcu_process_callbacks+0x100a/0x1ac0 kernel/rcu/tree.c:2697 kobject: 'iosched' (000000008cb9c9e2): kobject_uevent_env: filter function caused the event to drop! __do_softirq+0x308/0xb7e kernel/softirq.c:292 The buggy address belongs to the object at ffff8881a8c2f300 which belongs to the cache dentry of size 288 The buggy address is located 64 bytes inside of 288-byte region [ffff8881a8c2f300, ffff8881a8c2f420) The buggy address belongs to the page: page:ffffea0006a30bc0 count:1 mapcount:0 mapping:ffff8881da986cc0 index:0x0 flags: 0x2fffc0000000200(slab) raw: 02fffc0000000200 ffffea0007301088 ffffea0006a31f08 ffff8881da986cc0 kobject: 'integrity' (000000003bee9529): kobject_add_internal: parent: 'loop0', set: '' raw: 0000000000000000 ffff8881a8c2f040 000000010000000b 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881a8c2f200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881a8c2f280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff8881a8c2f300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ kobject: 'integrity' (000000003bee9529): kobject_uevent_env ffff8881a8c2f380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881a8c2f400: fb fb fb fb fc fc fc fc fc fc fc fc fb fb fb fb ==================================================================