================================================================== BUG: KASAN: use-after-free in debugfs_remove fs/debugfs/inode.c:657 [inline] BUG: KASAN: use-after-free in debugfs_remove+0xfb/0x120 fs/debugfs/inode.c:649 Read of size 8 at addr ffff88807492e9e0 by task syz-executor.0/16255 CPU: 1 PID: 16255 Comm: syz-executor.0 Not tainted 4.14.111 #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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+0xaf/0x2b5 mm/kasan/report.c:393 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430 debugfs_remove fs/debugfs/inode.c:657 [inline] debugfs_remove+0xfb/0x120 fs/debugfs/inode.c:649 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_ioctl+0x21d/0x270 kernel/trace/blktrace.c:708 blkdev_ioctl+0x106/0x1880 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+0x7b9/0x1070 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x458c29 RSP: 002b:00007f568e66fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458c29 RDX: 0000000000000000 RSI: 0000000000001276 RDI: 0000000000000005 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f568e6706d4 R13: 00000000004c012d R14: 00000000004d2540 R15: 00000000ffffffff Allocated by task 16224: 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+0x58/0x190 fs/namei.c:1562 lookup_one_len+0x281/0x3b0 fs/namei.c:2538 start_creating fs/debugfs/inode.c:309 [inline] start_creating+0xa6/0x1b0 fs/debugfs/inode.c:285 __debugfs_create_file+0x53/0x3d0 fs/debugfs/inode.c:348 debugfs_create_file+0x5a/0x70 fs/debugfs/inode.c:399 do_blk_trace_setup+0x32d/0xb10 kernel/trace/blktrace.c:529 blk_trace_setup+0xbd/0x140 kernel/trace/blktrace.c:579 blk_trace_ioctl+0x147/0x270 kernel/trace/blktrace.c:694 blkdev_ioctl+0x106/0x1880 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+0x7b9/0x1070 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 7018: 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 __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+0x7c0/0x12c0 kernel/rcu/tree.c:2946 __do_softirq+0x24e/0x9ae kernel/softirq.c:288 The buggy address belongs to the object at ffff88807492e9a0 which belongs to the cache dentry of size 288 The buggy address is located 64 bytes inside of 288-byte region [ffff88807492e9a0, ffff88807492eac0) The buggy address belongs to the page: page:ffffea0001d24b80 count:1 mapcount:0 mapping:ffff88807492e000 index:0x0 flags: 0x1fffc0000000100(slab) raw: 01fffc0000000100 ffff88807492e000 0000000000000000 000000010000000b raw: ffffea0002916c60 ffffea0002682920 ffff88821f8b5680 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88807492e880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88807492e900: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc >ffff88807492e980: fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807492ea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807492ea80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc kobject: 'loop2' (ffff8880a49245e0): kobject_uevent_env ================================================================== kobject: 'loop2' (ffff8880a49245e0): fill_kobj_path: path = '/devices/virtual/block/loop2'