================================================================== BUG: KASAN: use-after-free in relay_switch_subbuf+0x8be/0x920 kernel/relay.c:755 Read of size 8 at addr ffff888092a8fe18 by task syz-executor.0/2843 CPU: 1 PID: 2843 Comm: syz-executor.0 Not tainted 5.3.0-rc3 #117 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+0x12/0x17 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_irq_restore+0x35/0x60 arch/x86/include/asm/paravirt.h:768 Code: 48 b9 00 00 00 00 00 fc ff df 48 c1 ea 03 48 89 e5 48 83 ec 08 80 3c 0a 00 75 18 48 83 3d b2 58 2f 07 00 74 0c 48 89 c7 57 9d <0f> 1f 44 00 00 c9 c3 0f 0b 48 89 7d f8 48 c7 c7 10 f2 d2 88 e8 b2 RSP: 0018:ffff888052e878d8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffffdd RAX: 0000000000000286 RBX: 0000000000000000 RCX: dffffc0000000000 RDX: 1ffffffff11a5e42 RSI: ffffffff817805de RDI: 0000000000000286 RBP: ffff888052e878e0 R08: ffff88804f64a280 R09: ffffed1025fff979 R10: ffffed1025fff978 R11: ffff88812fffcbc3 R12: 0000000000000004 R13: 0000000000000000 R14: 0000000000000008 R15: ffffea0001550c30 rmqueue mm/page_alloc.c:3300 [inline] get_page_from_freelist+0x27a4/0x39d0 mm/page_alloc.c:3688 __alloc_pages_nodemask+0x2d0/0x900 mm/page_alloc.c:4725 __alloc_pages include/linux/gfp.h:473 [inline] __alloc_pages_node include/linux/gfp.h:486 [inline] alloc_pages_node include/linux/gfp.h:500 [inline] alloc_thread_stack_node kernel/fork.c:248 [inline] dup_task_struct kernel/fork.c:855 [inline] copy_process+0x3f8/0x6b00 kernel/fork.c:1856 _do_fork+0x146/0xfa0 kernel/fork.c:2369 __do_sys_clone kernel/fork.c:2524 [inline] __se_sys_clone kernel/fork.c:2505 [inline] __x64_sys_clone+0x18d/0x250 kernel/fork.c:2505 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c1f9 Code: ff 48 85 f6 0f 84 27 8e fb ff 48 83 ee 10 48 89 4e 08 48 89 3e 48 89 d7 4c 89 c2 4d 89 c8 4c 8b 54 24 08 b8 38 00 00 00 0f 05 <48> 85 c0 0f 8c fe 8d fb ff 74 01 c3 31 ed 48 f7 c7 00 00 01 00 75 RSP: 002b:0000000000a6fac8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fd9d4f1a700 RCX: 000000000045c1f9 RDX: 00007fd9d4f1a9d0 RSI: 00007fd9d4f19db0 RDI: 00000000003d0f00 RBP: 0000000000a6fce0 R08: 00007fd9d4f1a700 R09: 00007fd9d4f1a700 R10: 00007fd9d4f1a9d0 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000a6fb7f R14: 0000000000020000 R15: 00005555563a5c90 Allocated by task 32623: 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 32747: 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 ffff888092a8fdc0 which belongs to the cache dentry(17:syz0) of size 288 The buggy address is located 88 bytes inside of 288-byte region [ffff888092a8fdc0, ffff888092a8fee0) The buggy address belongs to the page: page:ffffea00024aa3c0 refcount:1 mapcount:0 mapping:ffff88808bef3540 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea0002536808 ffffea0002536648 ffff88808bef3540 raw: 0000000000000000 ffff888092a8f000 000000010000000b 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888092a8fd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888092a8fd80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff888092a8fe00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888092a8fe80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff888092a8ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================