================================================================== BUG: KASAN: use-after-free in relay_switch_subbuf+0x8be/0x920 kernel/relay.c:755 Read of size 8 at addr ffff888095a21cf8 by task kworker/u4:0/26094 CPU: 1 PID: 26094 Comm: kworker/u4:0 Not tainted 5.3.0-rc2+ #113 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker 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+0x12/0x17 mm/kasan/common.c:612 __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_rq+0x185/0x1f0 kernel/trace/blktrace.c:813 blk_add_trace_rq_complete+0x17a/0x1e0 kernel/trace/blktrace.c:842 trace_block_rq_complete include/trace/events/block.h:116 [inline] blk_update_request+0x851/0xc10 block/blk-core.c:1403 scsi_end_request+0x7f/0x840 drivers/scsi/scsi_lib.c:579 scsi_io_completion+0x20a/0x1420 drivers/scsi/scsi_lib.c:963 scsi_finish_command+0x3b7/0x670 drivers/scsi/scsi.c:228 scsi_softirq_done+0x326/0x3b0 drivers/scsi/scsi_lib.c:1465 blk_done_softirq+0x2fe/0x4d0 block/blk-softirq.c:37 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:537 [inline] do_IRQ+0x12c/0x200 arch/x86/kernel/irq.c:259 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:605 RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:763 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:785 [inline] RIP: 0010:__local_bh_disable_ip+0x39/0x1b0 kernel/softirq.c:116 Code: 8b 05 13 58 bc 7e a9 00 00 0f 00 0f 85 41 01 00 00 48 c7 c0 08 f2 d2 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 <0f> 85 2d 01 00 00 48 83 3d e1 4b 8d 07 00 0f 84 12 01 00 00 9c 58 RSP: 0018:ffff88808d77fc20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffdd RAX: 1ffffffff11a5e41 RBX: 0000000000000201 RCX: ffffffff87213e73 RDX: dffffc0000000000 RSI: 0000000000000201 RDI: ffffffff87213cb8 RBP: ffff88808d77fc38 R08: ffff88808bd7e680 R09: ffffed1014fe0af6 R10: ffffed1014fe0af5 R11: ffff8880a7f057ab R12: ffffffff87213cb8 R13: dffffc0000000000 R14: ffffffff87214900 R15: 0000000000000054 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:134 [inline] _raw_spin_lock_bh+0x17/0x50 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:343 [inline] batadv_nc_purge_paths+0xd8/0x370 net/batman-adv/network-coding.c:441 batadv_nc_worker+0x29c/0x760 net/batman-adv/network-coding.c:719 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Allocated by task 2770: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:487 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:460 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:495 slab_post_alloc_hook mm/slab.h:520 [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:1652 lookup_one_len+0x16d/0x1a0 fs/namei.c:2541 start_creating+0xc5/0x1d0 fs/debugfs/inode.c:312 __debugfs_create_file+0x65/0x3c0 fs/debugfs/inode.c:357 debugfs_create_file+0x5a/0x70 fs/debugfs/inode.c:413 kvm_create_vm_debugfs arch/x86/kvm/../../../virt/kvm/kvm_main.c:621 [inline] kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3451 [inline] kvm_dev_ioctl+0xa04/0x1650 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3478 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:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 27467: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:449 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457 __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:2114 [inline] rcu_core+0x67f/0x1580 kernel/rcu/tree.c:2314 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323 __do_softirq+0x262/0x98c kernel/softirq.c:292 The buggy address belongs to the object at ffff888095a21ca0 which belongs to the cache dentry(65:syz5) of size 288 The buggy address is located 88 bytes inside of 288-byte region [ffff888095a21ca0, ffff888095a21dc0) The buggy address belongs to the page: page:ffffea0002568840 refcount:1 mapcount:0 mapping:ffff8880981a5a80 index:0xffff888095a21040 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea0002564588 ffffea0001956688 ffff8880981a5a80 raw: ffff888095a21040 ffff888095a21040 000000010000000a 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888095a21b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888095a21c00: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc >ffff888095a21c80: fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888095a21d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888095a21d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================