| Message ID | 20211207103719.91117-1-hbathini@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v3,1/2] powerpc: handle kdump appropriately with crash_kexec_post_notifiers option | expand |
On Tue, 7 Dec 2021 16:07:18 +0530, Hari Bathini wrote: > Kdump can be triggered after panic_notifers since commit f06e5153f4ae2 > ("kernel/panic.c: add "crash_kexec_post_notifiers" option for kdump > after panic_notifers") introduced crash_kexec_post_notifiers option. > But using this option would mean smp_send_stop(), that marks all other > CPUs as offline, gets called before kdump is triggered. As a result, > kdump routines fail to save other CPUs' registers. To fix this, kdump > friendly crash_smp_send_stop() function was introduced with kernel > commit 0ee59413c967 ("x86/panic: replace smp_send_stop() with kdump > friendly version in panic path"). Override this kdump friendly weak > function to handle crash_kexec_post_notifiers option appropriately > on powerpc. > > [...] Applied to powerpc/next. [1/2] powerpc: handle kdump appropriately with crash_kexec_post_notifiers option https://git.kernel.org/powerpc/c/219572d2fc4135b5ce65c735d881787d48b10e71 [2/2] ppc64/fadump: fix inaccurate CPU state info in vmcore generated with panic https://git.kernel.org/powerpc/c/06e629c25daa519be620a8c17359ae8fc7a2e903 cheers
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index c23ee842c4c3..2d33c167b438 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -620,6 +620,36 @@ void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) } #endif +#ifdef CONFIG_NMI_IPI +static void crash_stop_this_cpu(struct pt_regs *regs) +#else +static void crash_stop_this_cpu(void *dummy) +#endif +{ + /* + * Just busy wait here and avoid marking CPU as offline to ensure + * register data is captured appropriately. + */ + while (1) + cpu_relax(); +} + +void crash_smp_send_stop(void) +{ + static bool stopped = false; + + if (stopped) + return; + + stopped = true; + +#ifdef CONFIG_NMI_IPI + smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, crash_stop_this_cpu, 1000000); +#else + smp_call_function(crash_stop_this_cpu, NULL, 0); +#endif /* CONFIG_NMI_IPI */ +} + #ifdef CONFIG_NMI_IPI static void nmi_stop_this_cpu(struct pt_regs *regs) {
Kdump can be triggered after panic_notifers since commit f06e5153f4ae2 ("kernel/panic.c: add "crash_kexec_post_notifiers" option for kdump after panic_notifers") introduced crash_kexec_post_notifiers option. But using this option would mean smp_send_stop(), that marks all other CPUs as offline, gets called before kdump is triggered. As a result, kdump routines fail to save other CPUs' registers. To fix this, kdump friendly crash_smp_send_stop() function was introduced with kernel commit 0ee59413c967 ("x86/panic: replace smp_send_stop() with kdump friendly version in panic path"). Override this kdump friendly weak function to handle crash_kexec_post_notifiers option appropriately on powerpc. Signed-off-by: Hari Bathini <hbathini@linux.ibm.com> [Fixed signature of crash_stop_this_cpu() - reported by lkp@intel.com] Reported-by: kernel test robot <lkp@intel.com> --- arch/powerpc/kernel/smp.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)