linux-kernel - [PATCH v3 1/1] kernel/crash_core: Add crashkernel=auto for vmcore creation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-Id: <20210211180814.69708-1-saeed.mirzamohammadi@oracle.com>
Date:   Thu, 11 Feb 2021 10:08:10 -0800
From:   Saeed Mirzamohammadi <saeed.mirzamohammadi@...cle.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     saeed.mirzamohammadi@...cle.com, john.p.donnelly@...cle.com,
        Dave Young <dyoung@...hat.com>, Baoquan He <bhe@...hat.com>,
        Vivek Goyal <vgoyal@...hat.com>,
        Jonathan Corbet <corbet@....net>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        "Guilherme G. Piccoli" <gpiccoli@...onical.com>,
        Kees Cook <keescook@...omium.org>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        YiFei Zhu <yifeifz2@...inois.edu>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Mike Rapoport <rppt@...nel.org>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Sami Tolvanen <samitolvanen@...gle.com>,
        Christian Brauner <christian.brauner@...ntu.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Andrey Konovalov <andreyknvl@...gle.com>,
        kexec@...ts.infradead.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v3 1/1] kernel/crash_core: Add crashkernel=auto for vmcore creation

This adds crashkernel=auto feature to configure reserved memory for
vmcore creation. CONFIG_CRASH_AUTO_STR is defined to be set for
different kernel distributions and different archs based on their
needs.

Signed-off-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@...cle.com>
Signed-off-by: John Donnelly <john.p.donnelly@...cle.com>
Tested-by: John Donnelly <john.p.donnelly@...cle.com>
---
 Documentation/admin-guide/kdump/kdump.rst     |  3 ++-
 .../admin-guide/kernel-parameters.txt         |  6 +++++
 arch/Kconfig                                  | 24 +++++++++++++++++++
 kernel/crash_core.c                           |  7 ++++++
 4 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
index 2da65fef2a1c..e55cdc404c6b 100644
--- a/Documentation/admin-guide/kdump/kdump.rst
+++ b/Documentation/admin-guide/kdump/kdump.rst
@@ -285,7 +285,8 @@ This would mean:
     2) if the RAM size is between 512M and 2G (exclusive), then reserve 64M
     3) if the RAM size is larger than 2G, then reserve 128M
 
-
+Or you can use crashkernel=auto to choose the crash kernel memory size
+based on the recommended configuration set for each arch.
 
 Boot into System Kernel
 =======================
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 7d4e523646c3..aa2099465458 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -736,6 +736,12 @@
 			a memory unit (amount[KMG]). See also
 			Documentation/admin-guide/kdump/kdump.rst for an example.
 
+	crashkernel=auto
+			[KNL] This parameter will set the reserved memory for
+			the crash kernel based on the value of the CRASH_AUTO_STR
+			that is the best effort estimation for each arch. See also
+			arch/Kconfig for further details.
+
 	crashkernel=size[KMG],high
 			[KNL, X86-64] range could be above 4G. Allow kernel
 			to allocate physical memory region from top, so could
diff --git a/arch/Kconfig b/arch/Kconfig
index af14a567b493..f87c88ffa2f8 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -14,6 +14,30 @@ menu "General architecture-dependent options"
 config CRASH_CORE
 	bool
 
+if CRASH_CORE
+
+config CRASH_AUTO_STR
+	string "Memory reserved for crash kernel"
+	depends on CRASH_CORE
+	default "1G-64G:128M,64G-1T:256M,1T-:512M"
+	help
+	  This configures the reserved memory dependent
+	  on the value of System RAM. The syntax is:
+	  crashkernel=<range1>:<size1>[,<range2>:<size2>,...][@offset]
+	              range=start-[end]
+
+	  For example:
+	      crashkernel=512M-2G:64M,2G-:128M
+
+	  This would mean:
+
+	      1) if the RAM is smaller than 512M, then don't reserve anything
+	         (this is the "rescue" case)
+	      2) if the RAM size is between 512M and 2G (exclusive), then reserve 64M
+	      3) if the RAM size is larger than 2G, then reserve 128M
+
+endif # CRASH_CORE
+
 config KEXEC_CORE
 	select CRASH_CORE
 	bool
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 106e4500fd53..ab0a2b4b1ffa 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -7,6 +7,7 @@
 #include <linux/crash_core.h>
 #include <linux/utsname.h>
 #include <linux/vmalloc.h>
+#include <linux/kexec.h>
 
 #include <asm/page.h>
 #include <asm/sections.h>
@@ -250,6 +251,12 @@ static int __init __parse_crashkernel(char *cmdline,
 	if (suffix)
 		return parse_crashkernel_suffix(ck_cmdline, crash_size,
 				suffix);
+#ifdef CONFIG_CRASH_AUTO_STR
+	if (strncmp(ck_cmdline, "auto", 4) == 0) {
+		ck_cmdline = CONFIG_CRASH_AUTO_STR;
+		pr_info("Using crashkernel=auto, the size chosen is a best effort estimation.\n");
+	}
+#endif
 	/*
 	 * if the commandline contains a ':', then that's the extended
 	 * syntax -- if not, it must be the classic syntax
-- 
2.27.0