================================================================== BUG: KASAN: use-after-free in relay_switch_subbuf+0x8be/0x920 kernel/relay.c:755 Read of size 8 at addr ffff8880960434b8 by task blkid/13694 CPU: 1 PID: 13694 Comm: blkid Not tainted 5.4.0-rc5+ #0 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.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:634 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 relay_switch_subbuf+0x8be/0x920 kernel/relay.c:755 relay_reserve include/linux/relay.h:261 [inline] trace_note.isra.0+0x5b8/0x6e0 kernel/trace/blktrace.c:93 trace_note_tsk kernel/trace/blktrace.c:124 [inline] __blk_add_trace+0xb70/0xe10 kernel/trace/blktrace.c:264 blk_add_trace_bio.isra.0+0x19c/0x220 kernel/trace/blktrace.c:865 blk_add_trace_bio_queue+0x46/0x60 kernel/trace/blktrace.c:902 trace_block_bio_queue include/trace/events/block.h:357 [inline] generic_make_request_checks+0x1b1a/0x2210 block/blk-core.c:966 generic_make_request+0x8f/0xb50 block/blk-core.c:1018 submit_bio+0x113/0x600 block/blk-core.c:1190 mpage_bio_submit fs/mpage.c:66 [inline] mpage_readpages+0x466/0x630 fs/mpage.c:410 blkdev_readpages+0x2d/0x40 fs/block_dev.c:620 read_pages+0x108/0x540 mm/readahead.c:126 __do_page_cache_readahead+0x4e0/0x5d0 mm/readahead.c:212 force_page_cache_readahead+0x1e9/0x360 mm/readahead.c:243 page_cache_sync_readahead mm/readahead.c:522 [inline] page_cache_sync_readahead+0x4b9/0x520 mm/readahead.c:509 generic_file_buffered_read mm/filemap.c:2051 [inline] generic_file_read_iter+0x1801/0x2c00 mm/filemap.c:2324 blkdev_read_iter+0x120/0x190 fs/block_dev.c:2010 call_read_iter include/linux/fs.h:1889 [inline] new_sync_read+0x4d7/0x800 fs/read_write.c:414 __vfs_read+0xe1/0x110 fs/read_write.c:427 vfs_read+0x1f0/0x440 fs/read_write.c:461 ksys_read+0x14f/0x290 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x73/0xb0 fs/read_write.c:595 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f00c596a310 Code: 73 01 c3 48 8b 0d 28 4b 2b 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 83 3d e5 a2 2b 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 6e 8a 01 00 48 89 04 24 RSP: 002b:00007fff18e5bee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f00c596a310 RDX: 0000000000000400 RSI: 0000000002108c58 RDI: 0000000000000003 RBP: 0000000002108c30 R08: 0000000000000028 R09: 0000000001680000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000002108030 R13: 0000000000000400 R14: 0000000002108080 R15: 0000000002108c48 Allocated by task 7506: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:510 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:483 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:518 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc mm/slab.c:3319 [inline] kmem_cache_alloc+0x121/0x710 mm/slab.c:3483 __d_alloc+0x2e/0x8c0 fs/dcache.c:1688 d_alloc+0x4d/0x280 fs/dcache.c:1767 d_alloc_parallel+0xf4/0x1c30 fs/dcache.c:2519 __lookup_slow+0x1ab/0x500 fs/namei.c:1646 lookup_one_len+0x16d/0x1a0 fs/namei.c:2533 start_creating+0xc5/0x1d0 fs/debugfs/inode.c:339 __debugfs_create_file+0x65/0x3f0 fs/debugfs/inode.c:384 debugfs_create_file+0x5a/0x70 fs/debugfs/inode.c:441 kvm_create_vm_debugfs arch/x86/kvm/../../../virt/kvm/kvm_main.c:622 [inline] kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3465 [inline] kvm_dev_ioctl+0xa50/0x1650 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3492 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+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] kasan_set_free_info mm/kasan/common.c:332 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:471 kasan_slab_free+0xe/0x10 mm/kasan/common.c:480 __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:2157 [inline] rcu_core+0x581/0x1560 kernel/rcu/tree.c:2377 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2386 __do_softirq+0x262/0x98c kernel/softirq.c:292 The buggy address belongs to the object at ffff888096043460 which belongs to the cache dentry(65:syz4) of size 288 The buggy address is located 88 bytes inside of 288-byte region [ffff888096043460, ffff888096043580) The buggy address belongs to the page: page:ffffea00025810c0 refcount:1 mapcount:0 mapping:ffff8880a854aa80 index:0xffff8880960435c0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea000258d748 ffffea00022da508 ffff8880a854aa80 raw: ffff8880960435c0 ffff888096043040 0000000100000005 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888096043380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888096043400: 00 00 00 00 fc fc fc fc fc fc fc fc fb fb fb fb >ffff888096043480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888096043500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888096043580: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ==================================================================