linux-kernel - [PATCH] depmod: create and use System.map.no

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Message-Id: <20191004095748.223119-1-maennich@google.com>
Date:   Fri,  4 Oct 2019 10:57:48 +0100
From:   Matthias Maennich <maennich@...gle.com>
To:     linux-kernel@...r.kernel.org
Cc:     kernel-team@...roid.com, maennich@...gle.com,
        Stefan Wahren <stefan.wahren@...e.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Lucas De Marchi <lucas.de.marchi@...il.com>,
        Jessica Yu <jeyu@...nel.org>,
        Martijn Coenen <maco@...roid.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-modules@...r.kernel.org
Subject: [PATCH] depmod: create and use System.map.no_namespaces

depmod in its current version is not aware of symbol namespace in
ksymtab entries introduced with 8651ec01daed ("module: add support for
symbol namespaces."). They have the form

  __ksymtab_NAMESPACE.symbol_name

A fix for kmod's depmod has been proposed [1]. In order to support older
versions of depmod as well, create a System.map.no_namespaces during
scripts/depmod.sh that has the pre-namespaces format. That way users do
not immediately upgrade the userspace tool.

[1] https://lore.kernel.org/linux-modules/20191004094136.166621-1-maennich@google.com/

Reported-by: Stefan Wahren <stefan.wahren@...e.com>
Fixes: 8651ec01daed ("module: add support for symbol namespaces.")
Cc: Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc: Lucas De Marchi <lucas.de.marchi@...il.com>
Cc: Jessica Yu <jeyu@...nel.org>
Cc: Martijn Coenen <maco@...roid.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: linux-modules@...r.kernel.org
Signed-off-by: Matthias Maennich <maennich@...gle.com>
---

Please note this depends on the new ksymtab entry format proposed in
https://lore.kernel.org/lkml/20191003075826.7478-2-yamada.masahiro@socionext.com/

That is likely to be merged soon as well as it fixes problems in 5.4-rc*, hence
this patch depends on it.

Cheers,
Matthias

 .gitignore        | 1 +
 scripts/depmod.sh | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/.gitignore b/.gitignore
index 70580bdd352c..5ed58a7cb433 100644
--- a/.gitignore
+++ b/.gitignore
@@ -59,6 +59,7 @@ modules.order
 /vmlinux-gdb.py
 /vmlinuz
 /System.map
+/System.map.no_namespaces
 /Module.markers
 /modules.builtin.modinfo
 
diff --git a/scripts/depmod.sh b/scripts/depmod.sh
index e083bcae343f..602e1af072c7 100755
--- a/scripts/depmod.sh
+++ b/scripts/depmod.sh
@@ -39,7 +39,13 @@ if $depmod_hack_needed; then
 	KERNELRELEASE=99.98.$KERNELRELEASE
 fi
 
-set -- -ae -F System.map
+# Older versions of depmod do not support symbol namespaces in ksymtab entries,
+# hence create an alternative System.map with namespace patched out to use for
+# depmod. I.e. transform entries as follows:
+#    __ksymtab_NAMESPACE.symbol_name -> __ksymtab_symbol_name
+sed 's/__ksymtab_.*\./__ksymtab_/' System.map > System.map.no_namespaces
+
+set -- -ae -F System.map.no_namespaces
 if test -n "$INSTALL_MOD_PATH"; then
 	set -- "$@" -b "$INSTALL_MOD_PATH"
 fi
-- 
2.23.0.581.g78d2f28ef7-goog