In https://git.kernel.org/torvalds/c/07fa619f2a40c there is a test program which uses kexec to invoke a 4-instruction 'executable' which merely writes a byte to a serial port and returns. It just loads a single kexec segment containing those four instructions. Should I have been able to do that using kexec-tools? I couldn't work out how. And even once it's loaded, 'kexec -f -e' does manage to invoke it, but then reports 'No such file or directory' after the reboot() system call returns success. Strace shows: reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, LINUX_REBOOT_CMD_KEXEC[ 143.979879] Freezing user space processes [ 143.981493] Freezing user space processes completed (elapsed 0.000 seconds) [ 143.982148] OOM killer disabled. [ 143.999573] Disabling non-boot CPUs ... [ 144.017504] smpboot: CPU 1 is now offline [ 144.018298] crash hp: kexec_trylock() failed, kdump image may be inaccurate B[ 144.034246] Enabling non-boot CPUs ... [ 144.034666] crash hp: kexec_trylock() failed, kdump image may be inaccurate [ 144.035396] smpboot: Booting Node 0 Processor 1 APIC 0x1 [ 144.037406] CPU1 is up [ 144.042020] virtio_blk virtio1: 2/0/0 default/read/poll queues [ 144.046702] OOM killer enabled. [ 144.047368] Restarting tasks ... done. ) = 0 write(2, "kexec failed: No such file or di"..., 40kexec failed: No such file or directory ) = 40 exit_group(-1) = ? +++ exited with 255 +++
<<attachment: smime.p7s>>
