From: Borislav Petkov <bp@alien8.de>
To: kexec@lists.infradead.org
Subject: [PATCH v7 2/8] x86/crash: Introduce new options to support cpu and memory hotplug
Date: Wed, 27 Apr 2022 12:48:09 +0200 [thread overview]
Message-ID: <YmkfaSAiGIYgTlvY@zn.tnic> (raw)
In-Reply-To: <0aee5cd1-eb8c-f778-c6e5-7f5ca3624d15@oracle.com>
On Tue, Apr 26, 2022 at 03:08:26PM -0500, Eric DeVolder wrote:
> Why is it safe to examine kexec_crash_image outside the mutex? As I
> understand it, there is still the (very rare) opportunity for a kdump
> load/unload initiated via userland and this check to collide. (Similarly, I
> believe the mutex entry is almost always assured/likely.)
Yeah, I guess. As the comment in do_kexec_load() says
"KISS: always take the mutex."
so ignore this part of the diff and let's always grab the mutex.
Sorry for the confusion.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@alien8.de>
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, bhe@redhat.com, vgoyal@redhat.com,
tglx@linutronix.de, mingo@redhat.com,
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 2/8] x86/crash: Introduce new options to support cpu and memory hotplug
Date: Wed, 27 Apr 2022 12:48:09 +0200 [thread overview]
Message-ID: <YmkfaSAiGIYgTlvY@zn.tnic> (raw)
In-Reply-To: <0aee5cd1-eb8c-f778-c6e5-7f5ca3624d15@oracle.com>
On Tue, Apr 26, 2022 at 03:08:26PM -0500, Eric DeVolder wrote:
> Why is it safe to examine kexec_crash_image outside the mutex? As I
> understand it, there is still the (very rare) opportunity for a kdump
> load/unload initiated via userland and this check to collide. (Similarly, I
> believe the mutex entry is almost always assured/likely.)
Yeah, I guess. As the comment in do_kexec_load() says
"KISS: always take the mutex."
so ignore this part of the diff and let's always grab the mutex.
Sorry for the confusion.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-04-27 10:48 UTC|newest]
Thread overview: 73+ 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 ` 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 16:42 ` 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
2022-04-28 9:49 ` David Hildenbrand
2022-04-13 16:42 ` [PATCH v7 2/8] x86/crash: Introduce new options to support cpu and memory hotplug Eric DeVolder
2022-04-13 16:42 ` Eric DeVolder
2022-04-14 13:59 ` Borislav Petkov
2022-04-14 13:59 ` Borislav Petkov
2022-04-18 22:03 ` Eric DeVolder
2022-04-18 22:03 ` Eric DeVolder
2022-04-19 10:32 ` Borislav Petkov
2022-04-19 10:32 ` Borislav Petkov
2022-04-19 21:58 ` Eric DeVolder
2022-04-19 21:58 ` Eric DeVolder
2022-04-25 19:25 ` Borislav Petkov
2022-04-25 19:25 ` Borislav Petkov
2022-04-26 20:08 ` Eric DeVolder
2022-04-26 20:08 ` Eric DeVolder
2022-04-27 10:48 ` Borislav Petkov [this message]
2022-04-27 10:48 ` Borislav Petkov
2022-04-26 4:21 ` Sourabh Jain
2022-04-26 4:21 ` Sourabh Jain
2022-04-26 14:39 ` Eric DeVolder
2022-04-26 14:39 ` Eric DeVolder
2022-04-29 6:41 ` Sourabh Jain
2022-04-29 6:41 ` Sourabh Jain
2022-05-05 16:31 ` Eric DeVolder
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 ` Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 4/8] crash: add generic infrastructure for crash hotplug support Eric DeVolder
2022-04-13 16:42 ` Eric DeVolder
2022-04-14 2:45 ` Baoquan He
2022-04-14 2:45 ` Baoquan He
2022-04-14 22:29 ` Eric DeVolder
2022-04-14 22:29 ` Eric DeVolder
2022-04-18 3:17 ` Baoquan He
2022-04-18 3:17 ` Baoquan He
2022-04-26 4:06 ` Sourabh Jain
2022-04-26 4:06 ` Sourabh Jain
2022-04-26 5:22 ` Baoquan He
2022-04-26 5:22 ` Baoquan He
2022-04-28 5:18 ` Sourabh Jain
2022-04-28 5:18 ` Sourabh Jain
2022-05-04 18:11 ` Eric DeVolder
2022-05-04 18:11 ` Eric DeVolder
2022-05-05 5:45 ` Baoquan He
2022-05-05 5:45 ` Baoquan He
2022-05-05 9:59 ` Sourabh Jain
2022-05-05 9:59 ` Sourabh Jain
2022-05-05 11:04 ` Baoquan He
2022-05-05 11:04 ` Baoquan He
2022-05-05 13:35 ` Eric DeVolder
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 ` Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 6/8] kexec: exclude hot remove cpu from elfcorehdr notes Eric DeVolder
2022-04-13 16:42 ` Eric DeVolder
2022-04-14 2:48 ` Baoquan He
2022-04-14 2:48 ` Baoquan He
2022-04-14 22:31 ` Eric DeVolder
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
2022-04-13 16:42 ` Eric DeVolder
2022-04-14 2:52 ` Baoquan He
2022-04-14 2:52 ` Baoquan He
2022-04-14 22:32 ` Eric DeVolder
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
2022-04-13 16:42 ` Eric DeVolder
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