Warning: Permanently added '10.128.0.9' (ECDSA) to the list of known hosts. executing program login: Kernel page fault with the following non-sleepable locks held: exclusive sleep mutex pipe mutex (pipe mutex) r = 0 (0xfffff80004c405c8) locked @ /syzkaller/managers/main/kernel/sys/kern/sys_pipe.c:964 stack backtrace: #0 0xffffffff8110b80e at witness_debugger+0x8e #1 0xffffffff8110ce90 at witness_warn+0x640 #2 0xffffffff817166a0 at trap_pfault+0x80 #3 0xffffffff8171560d at trap+0x44d #4 0xffffffff816deae5 at calltrap+0x8 #5 0xffffffff811180a8 at pipe_write+0x16d8 #6 0xffffffff8111252d at dofilewrite+0xfd #7 0xffffffff81111f26 at kern_writev+0x66 #8 0xffffffff81112410 at sys_writev+0x50 #9 0xffffffff81717806 at amd64_syscall+0x436 #10 0xffffffff816df3cd at fast_syscall_common+0x101 Fatal trap 12: page fault while in kernel mode cpuid = 1; apic id = 01 fault virtual address = 0x30 fault code = supervisor read data , page not present instruction pointer = 0x20:0xffffffff8156dbda stack pointer = 0x28:0xfffffe00212187a0 frame pointer = 0x28:0xfffffe00212187e0 code segment = base 0x0, limit 0xfffff, type 0x1b = DPL 0, pres 1, long 1, def32 0, gran 1 processor eflags = interrupt enabled, resume, IOPL = 0 current process = 759 (syz-executor3299822) trap number = 12 panic: page fault cpuid = 1 time = 1552900717 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe0021218400 vpanic() at vpanic+0x1e0/frame 0xfffffe0021218460 panic() at panic+0x43/frame 0xfffffe00212184c0 trap_fatal() at trap_fatal+0x4c6/frame 0xfffffe0021218540 trap_pfault() at trap_pfault+0x9f/frame 0xfffffe00212185b0 trap() at trap+0x44d/frame 0xfffffe00212186d0 calltrap() at calltrap+0x8/frame 0xfffffe00212186d0 --- trap 0xc, rip = 0xffffffff8156dbda, rsp = 0xfffffe00212187a0, rbp = 0xfffffe00212187e0 --- vm_page_unhold_pages() at vm_page_unhold_pages+0x5a/frame 0xfffffe00212187e0 pipe_write() at pipe_write+0x16d8/frame 0xfffffe00212188b0 dofilewrite() at dofilewrite+0xfd/frame 0xfffffe0021218910 kern_writev() at kern_writev+0x66/frame 0xfffffe0021218950 sys_writev() at sys_writev+0x50/frame 0xfffffe0021218980 amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe0021218ab0 fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe0021218ab0 --- syscall (0, FreeBSD ELF64, nosys), rip = 0x4575ba, rsp = 0x7fffdfffdf88, rbp = 0x6b5ac8 --- KDB: enter: panic [ thread pid 759 tid 100098 ] Stopped at kdb_enter+0x6a: movq $0,kdb_why