From: Baoquan He <bhe@redhat.com>
To: Eric DeVolder <eric.devolder@oracle.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
kexec@lists.infradead.org, ebiederm@xmission.com,
dyoung@redhat.com, vgoyal@redhat.com, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
hpa@zytor.com, nramas@linux.microsoft.com,
thomas.lendacky@amd.com, robh@kernel.org, efault@gmx.de,
rppt@kernel.org, david@redhat.com, konrad.wilk@oracle.com,
boris.ostrovsky@oracle.com
Subject: Re: [PATCH v7 6/8] kexec: exclude hot remove cpu from elfcorehdr notes
Date: Thu, 14 Apr 2022 10:48:30 +0800 [thread overview]
Message-ID: <YleLfoQcDXnlB/ZW@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20220413164237.20845-7-eric.devolder@oracle.com>
On 04/13/22 at 12:42pm, Eric DeVolder wrote:
> 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
> crash_hotplug_handler(). Thus the CPU must be explicitly excluded
> when building the new list of CPUs.
>
> This change identifies in crash_hotplug_handler() the CPU to be
> excluded, and the check for excluding the CPU in
> crash_prepare_elf64_headers().
>
> Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
> Acked-by: Baoquan He <bhe@redhat.com>
This patch is updated, the old ack should be removed. It looks better to
put the offlinecpu assignment here.
Ack it again.
Acked-by: Baoquan He <bhe@redhat.com>
> ---
> kernel/crash_core.c | 9 +++++++++
> kernel/kexec_file.c | 5 +++++
> 2 files changed, 14 insertions(+)
>
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index ecf746243ab2..036243b1f252 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -521,6 +521,15 @@ static void crash_hotplug_handler(unsigned int hp_action,
> /* 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 : ~0U;
> +
> /* Now invoke arch-specific update handler */
> arch_crash_hotplug_handler(kexec_crash_image, hp_action, cpu);
>
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> index 94a459209111..9d5c4eea0179 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) {
> +#ifdef CONFIG_CRASH_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
>
next prev parent reply other threads:[~2022-04-14 2:48 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-13 16:42 [PATCH v7 0/8] crash: Kernel handling of CPU and memory hot un/plug Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 1/8] x86/crash: fix minor typo/bug in debug message Eric DeVolder
2022-04-13 17:52 ` [tip: x86/kdump] x86/crash: Fix " tip-bot2 for Eric DeVolder
2022-04-28 9:49 ` [PATCH v7 1/8] x86/crash: fix " David Hildenbrand
2022-04-13 16:42 ` [PATCH v7 2/8] x86/crash: Introduce new options to support cpu and memory hotplug Eric DeVolder
2022-04-14 13:59 ` Borislav Petkov
2022-04-18 22:03 ` Eric DeVolder
2022-04-19 10:32 ` Borislav Petkov
2022-04-19 21:58 ` Eric DeVolder
2022-04-25 19:25 ` Borislav Petkov
2022-04-26 20:08 ` Eric DeVolder
2022-04-27 10:48 ` Borislav Petkov
2022-04-26 4:21 ` Sourabh Jain
2022-04-26 14:39 ` Eric DeVolder
2022-04-29 6:41 ` Sourabh Jain
2022-05-05 16:31 ` Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 3/8] crash: prototype change for crash_prepare_elf64_headers Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 4/8] crash: add generic infrastructure for crash hotplug support Eric DeVolder
2022-04-14 2:45 ` Baoquan He
2022-04-14 22:29 ` Eric DeVolder
2022-04-18 3:17 ` Baoquan He
2022-04-26 4:06 ` Sourabh Jain
2022-04-26 5:22 ` Baoquan He
2022-04-28 5:18 ` Sourabh Jain
2022-05-04 18:11 ` Eric DeVolder
2022-05-05 5:45 ` Baoquan He
2022-05-05 9:59 ` Sourabh Jain
2022-05-05 11:04 ` Baoquan He
2022-05-05 13:35 ` Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 5/8] kexec: exclude elfcorehdr from the segment digest Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 6/8] kexec: exclude hot remove cpu from elfcorehdr notes Eric DeVolder
2022-04-14 2:48 ` Baoquan He [this message]
2022-04-14 22:31 ` Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 7/8] x86/crash: Add x86 crash hotplug support for kexec_file_load Eric DeVolder
2022-04-14 2:52 ` Baoquan He
2022-04-14 22:32 ` Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 8/8] x86/crash: Add x86 crash hotplug support for kexec_load Eric DeVolder
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