From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric DeVolder Date: Thu, 5 May 2022 14:46:01 -0400 Subject: [PATCH v8 5/7] kexec: exclude hot remove cpu from elfcorehdr notes In-Reply-To: <20220505184603.1548-1-eric.devolder@oracle.com> References: <20220505184603.1548-1-eric.devolder@oracle.com> Message-ID: <20220505184603.1548-6-eric.devolder@oracle.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kexec@lists.infradead.org Due to use of CPUHP_AP_ONLINE_DYN, upon CPU unplug, the CPU is still in the for_each_present_cpu() list when within the handle_hotplug_event(). Thus the CPU must be explicitly excluded when building the new list of CPUs. This change identifies in handle_hotplug_event() the CPU to be excluded, and the check for excluding the CPU in crash_prepare_elf64_headers(). Signed-off-by: Eric DeVolder --- kernel/crash_core.c | 10 ++++++++++ kernel/kexec_file.c | 5 +++++ 2 files changed, 15 insertions(+) diff --git a/kernel/crash_core.c b/kernel/crash_core.c index f197af50def6..7ba43f058d82 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -520,6 +520,16 @@ static void handle_hotplug_event(unsigned int hp_action, unsigned int cpu) /* Flag to differentiate between normal load and hotplug */ kexec_crash_image->hotplug_event = true; + /* + * Due to use of CPUHP_AP_ONLINE_DYN, upon unplug and during + * this callback, the CPU is still in the for_each_present_cpu() + * list. Must explicitly look to exclude this CPU when building + * new list. + */ + kexec_crash_image->offlinecpu = + (hp_action == KEXEC_CRASH_HP_REMOVE_CPU) ? + cpu : KEXEC_CRASH_HP_INVALID_CPU; + /* Now invoke arch-specific update handler */ arch_crash_handle_hotplug_event(kexec_crash_image, hp_action, cpu); diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index aacdf93c3507..d68e5769b428 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -1314,6 +1314,11 @@ int crash_prepare_elf64_headers(struct kimage *image, struct crash_mem *mem, /* Prepare one phdr of type PT_NOTE for each present CPU */ for_each_present_cpu(cpu) { +#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_MEMORY_HOTPLUG) + /* Skip the soon-to-be offlined cpu */ + if (image->hotplug_event && (cpu == image->offlinecpu)) + continue; +#endif phdr->p_type = PT_NOTE; notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu)); phdr->p_offset = phdr->p_paddr = notes_addr; -- 2.27.0