From: Dengcheng Zhu Date: Wed, 26 Sep 2018 19:49:10 +0000 (+0000) Subject: MIPS: kdump: Mark cpu back online before rebooting X-Git-Tag: v4.20-rc1~95^2~21 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=82689ac663ac2f3fe89231b2f929fbdae178bb81;p=linux.git MIPS: kdump: Mark cpu back online before rebooting The crash utility initializes cpu state by reading the system kernel memory, which is copied into vmcore. It is also natural to preserve the online state for CPUs at crash. Failing to do so could make the analysis tool present info for only 1 CPU by default, and unable to find panic task. Signed-off-by: Dengcheng Zhu Signed-off-by: Paul Burton Patchwork: https://patchwork.linux-mips.org/patch/20809/ Cc: Paul Burton Cc: "ralf@linux-mips.org" Cc: "linux-mips@linux-mips.org" Cc: "rachel.mozes@intel.com" --- diff --git a/arch/mips/kernel/machine_kexec.c b/arch/mips/kernel/machine_kexec.c index 35175eb2e8b0..93936dce04d6 100644 --- a/arch/mips/kernel/machine_kexec.c +++ b/arch/mips/kernel/machine_kexec.c @@ -173,6 +173,16 @@ void kexec_reboot(void) { void (*do_kexec)(void) __noreturn; + /* + * We know we were online, and there will be no incoming IPIs at + * this point. Mark online again before rebooting so that the crash + * analysis tool will see us correctly. + */ + set_cpu_online(smp_processor_id(), true); + + /* Ensure remote CPUs observe that we're online before rebooting. */ + smp_mb__after_atomic(); + #ifdef CONFIG_SMP if (smp_processor_id() > 0) { /*