On Thu, Aug 17, 2017 at 11:24:27AM +0900, Hoeun Ryu wrote: > Commit 0ee5941 : (x86/panic: replace smp_send_stop() with kdump friendly > version in panic path) introduced crash_smp_send_stop() which is a weak > function and can be overridden by architecture codes to fix the side effect > caused by commit f06e515 : (kernel/panic.c: add "crash_kexec_post_ > notifiers" option). > > ARM64 architecture uses the weak version function and the problem is that > the weak function simply calls smp_send_stop() which makes other CPUs > offline and takes away the chance to save crash information for nonpanic > CPUs in machine_crash_shutdown() when crash_kexec_post_notifiers kernel > option is enabled. > > Calling smp_send_crash_stop() in machine_crash_shutdown() is useless > because all nonpanic CPUs are already offline by smp_send_stop() in this > case and smp_send_crash_stop() only works against online CPUs. > > The result is that secondary CPUs registers are not saved by > crash_save_cpu() and the vmcore file misreports these CPUs as being > offline. > > crash_smp_send_stop() is implemented to fix this problem by replacing the > existing smp_send_crash_stop() and adding a check for multiple calling to > the function. The function (strong symbol version) saves crash information > for nonpanic CPUs and machine_crash_shutdown() tries to save crash > information for nonpanic CPUs only when crash_kexec_post_notifiers kernel > option is disabled. > > * crash_kexec_post_notifiers : false > > panic() > __crash_kexec() > machine_crash_shutdown() > crash_smp_send_stop() <= save crash dump for nonpanic cores > > * crash_kexec_post_notifiers : true > > panic() > crash_smp_send_stop() <= save crash dump for nonpanic cores > __crash_kexec() > machine_crash_shutdown() > crash_smp_send_stop() <= just return. > > Signed-off-by: Hoeun Ryu <hoeun....@gmail.com> > Reviewed-by: James Morse <james.mo...@arm.com> > Tested-by: James Morse <james.mo...@arm.com>
Queued for 4.14. Thanks. -- Catalin