mirror of
https://github.com/JakeHillion/drgn.git
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74 lines
2.3 KiB
Python
74 lines
2.3 KiB
Python
# Copyright (c) Meta Platforms, Inc. and affiliates.
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# SPDX-License-Identifier: LGPL-2.1-or-later
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import ctypes
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import os
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import re
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import subprocess
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from util import NORMALIZED_MACHINE_NAME, SYS
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KEXEC_FILE_ON_CRASH = 2
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KEXEC_FILE_NO_INITRAMFS = 4
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def main() -> None:
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with open("/proc/cmdline", "rb") as f:
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cmdline = f.read().rstrip(b"\n")
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cmdline = re.sub(rb"(^|\s)crashkernel=\S+", b"", cmdline)
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# `nokaslr` is required to avoid sporadically failing to reserve space for the
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# capture kernel
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cmdline += b" nokaslr"
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if os.getenv("KDUMP_NEEDS_NOSMP"):
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# `nosmp` is required to avoid QEMU sporadically failing an internal
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# assertion when using emulation.
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cmdline += b" nosmp"
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vmlinuz = f"/lib/modules/{os.uname().release}/vmlinuz"
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# On x86-64, kexec_file_load() is supported on all kernel versions we care
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# about, and it's simple enough to call ourselves. On other architectures,
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# we just use kexec(8).
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if NORMALIZED_MACHINE_NAME == "x86_64":
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syscall = ctypes.CDLL(None, use_errno=True).syscall
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syscall.restype = ctypes.c_long
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with open(vmlinuz, "rb") as kernel:
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if syscall(
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ctypes.c_long(SYS["kexec_file_load"]),
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ctypes.c_int(kernel.fileno()),
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ctypes.c_int(-1),
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ctypes.c_ulong(len(cmdline) + 1),
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ctypes.c_char_p(cmdline + b"\0"),
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ctypes.c_ulong(KEXEC_FILE_ON_CRASH | KEXEC_FILE_NO_INITRAMFS),
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):
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errno = ctypes.get_errno()
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raise OSError(errno, os.strerror(errno))
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else:
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subprocess.check_call(
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[
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"kexec",
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"--load-panic",
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"--kexec-syscall-auto",
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"--command-line=" + cmdline.decode(),
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vmlinuz,
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]
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)
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with open("/proc/self/comm", "w") as f:
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f.write("selfdestruct")
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# Avoid panicking from CPU 0 on s390x. See _skip_if_cpu0_on_s390x().
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if NORMALIZED_MACHINE_NAME == "s390x":
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cpus = os.sched_getaffinity(0)
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cpus.remove(0)
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if cpus:
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os.sched_setaffinity(0, cpus)
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with open("/proc/sysrq-trigger", "w") as f:
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f.write("c")
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if __name__ == "__main__":
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main()
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