================================================================== BUG: KASAN: use-after-free in debugfs_remove+0x10d/0x130 fs/debugfs/inode.c:683 Read of size 8 at addr ffff88809529e040 by task syz-executor.1/10477 CPU: 1 PID: 10477 Comm: syz-executor.1 Not tainted 5.2.0-rc6-next-20190624 #21 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482 kasan_report+0x12/0x20 mm/kasan/common.c:614 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 debugfs_remove+0x10d/0x130 fs/debugfs/inode.c:683 blk_trace_free+0x38/0x140 kernel/trace/blktrace.c:312 blk_trace_cleanup kernel/trace/blktrace.c:339 [inline] __blk_trace_remove+0x78/0xa0 kernel/trace/blktrace.c:352 blk_trace_ioctl+0x239/0x300 kernel/trace/blktrace.c:725 blkdev_ioctl+0x126/0x1c20 block/ioctl.c:592 block_ioctl+0xee/0x130 fs/block_dev.c:1930 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/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+0xfd/0x6a0 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459519 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f9a7ebbac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459519 RDX: 0000000000000000 RSI: 0000000000001276 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9a7ebbb6d4 R13: 00000000004c0b93 R14: 00000000004d39e0 R15: 00000000ffffffff Allocated by task 10477: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_kmalloc mm/kasan/common.c:489 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:497 slab_post_alloc_hook mm/slab.h:511 [inline] slab_alloc mm/slab.c:3319 [inline] kmem_cache_alloc+0x121/0x710 mm/slab.c:3483 __d_alloc+0x2e/0x8c0 fs/dcache.c:1622 d_alloc+0x4d/0x280 fs/dcache.c:1701 d_alloc_parallel+0xf4/0x1c30 fs/dcache.c:2453 __lookup_slow+0x1ab/0x500 fs/namei.c:1652 lookup_one_len+0x16d/0x1a0 fs/namei.c:2541 start_creating fs/debugfs/inode.c:307 [inline] start_creating+0xbf/0x1e0 fs/debugfs/inode.c:283 __debugfs_create_file+0x65/0x3d0 fs/debugfs/inode.c:346 debugfs_create_file+0x5a/0x70 fs/debugfs/inode.c:399 do_blk_trace_setup+0x361/0xb50 kernel/trace/blktrace.c:524 __blk_trace_setup+0xe3/0x190 kernel/trace/blktrace.c:571 blk_trace_ioctl+0x170/0x300 kernel/trace/blktrace.c:710 blkdev_ioctl+0x126/0x1c20 block/ioctl.c:592 block_ioctl+0xee/0x130 fs/block_dev.c:1930 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/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+0xfd/0x6a0 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 16: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459 __cache_free mm/slab.c:3425 [inline] kmem_cache_free+0x86/0x320 mm/slab.c:3693 __d_free+0x20/0x30 fs/dcache.c:271 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2092 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline] rcu_core+0xa3a/0x15a0 kernel/rcu/tree.c:2291 __do_softirq+0x262/0x98c kernel/softirq.c:292 The buggy address belongs to the object at ffff88809529e000 which belongs to the cache dentry(33:syz1) of size 288 The buggy address is located 64 bytes inside of 288-byte region [ffff88809529e000, ffff88809529e120) The buggy address belongs to the page: page:ffffea000254a780 refcount:1 mapcount:0 mapping:ffff8880a3fefa80 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea00024b0e88 ffffea000225b008 ffff8880a3fefa80 raw: 0000000000000000 ffff88809529e000 000000010000000b 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809529df00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809529df80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88809529e000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809529e080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809529e100: fb fb fb fb fc fc fc fc fc fc fc fc fb fb fb fb 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