================================================================== BUG: KASAN: stack-out-of-bounds in deref_stack_regs arch/x86/kernel/unwind_orc.c:290 [inline] BUG: KASAN: stack-out-of-bounds in unwind_next_frame+0x1595/0x1930 arch/x86/kernel/unwind_orc.c:420 Read of size 8 at addr ffff8801c690f6d0 by task syz-executor901/2295 CPU: 0 PID: 2295 Comm: syz-executor901 Not tainted 4.14.67+ #1 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 print_address_description+0x60/0x22b mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report.cold.6+0x11b/0x2dd mm/kasan/report.c:409 deref_stack_regs arch/x86/kernel/unwind_orc.c:290 [inline] unwind_next_frame+0x1595/0x1930 arch/x86/kernel/unwind_orc.c:420 perf_callchain_kernel+0x39c/0x540 arch/x86/events/core.c:2354 get_perf_callchain+0x2eb/0x760 kernel/events/callchain.c:217 perf_callchain+0x14a/0x190 kernel/events/callchain.c:190 perf_prepare_sample+0x704/0x13c0 kernel/events/core.c:6130 __perf_event_output kernel/events/core.c:6246 [inline] perf_event_output_forward+0xeb/0x230 kernel/events/core.c:6264 __perf_event_overflow+0x116/0x320 kernel/events/core.c:7500 perf_swevent_overflow+0x166/0x1f0 kernel/events/core.c:7576 perf_swevent_event+0x112/0x270 kernel/events/core.c:7614 perf_tp_event+0x5e5/0x790 kernel/events/core.c:8038 perf_trace_run_bpf_submit+0x10f/0x170 kernel/events/core.c:8008 perf_trace_lock+0x2f6/0x4c0 include/trace/events/lock.h:39 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0x4dc/0x720 kernel/locking/lockdep.c:4009 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_unlock_irqrestore+0x1b/0x70 kernel/locking/spinlock.c:192 __debug_check_no_obj_freed lib/debugobjects.c:758 [inline] debug_check_no_obj_freed+0x2b2/0x77c lib/debugobjects.c:774 slab_free_hook mm/slub.c:1382 [inline] slab_free_freelist_hook mm/slub.c:1410 [inline] slab_free mm/slub.c:2966 [inline] kmem_cache_free+0x218/0x350 mm/slub.c:2988 kfree_skbmem+0x9e/0x100 net/core/skbuff.c:582 __kfree_skb net/core/skbuff.c:642 [inline] kfree_skb+0xd0/0x340 net/core/skbuff.c:659 tun_queue_purge+0x108/0x300 drivers/net/tun.c:531 __tun_detach+0x3b9/0xa10 drivers/net/tun.c:571 tun_detach drivers/net/tun.c:594 [inline] tun_chr_close+0x40/0x50 drivers/net/tun.c:2662 __fput+0x25e/0x6f0 fs/file_table.c:210 task_work_run+0x116/0x190 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x8f8/0x2800 kernel/exit.c:865 do_group_exit+0x100/0x2e0 kernel/exit.c:968 get_signal+0x4e5/0x1470 kernel/signal.c:2348 do_signal+0x8f/0x1660 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0x116/0x150 arch/x86/entry/common.c:159 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:267 [inline] do_syscall_64+0x35d/0x4b0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x447679 RSP: 002b:00007f2ef2c5ecf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00000000006ddc28 RCX: 0000000000447679 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00000000006ddc28 RBP: 00000000006ddc20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006ddc2c R13: 00007ffc61b7646f R14: 00007f2ef2c5f9c0 R15: 0000000000000000 The buggy address belongs to the page: page:ffffea00071a43c0 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000000() raw: 4000000000000000 0000000000000000 0000000000000000 00000000ffffffff raw: 0000000000000000 ffffea00071a43e0 0000000000000000 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c690f580: 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 04 f2 ffff8801c690f600: f2 f2 f2 f2 f2 f2 00 f2 f2 f2 00 00 00 00 00 00 >ffff8801c690f680: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 04 f2 f2 f2 ^ ffff8801c690f700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8801c690f780: 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f2 f2 ==================================================================