From 586dcb3d2ccd8e45c78d3d140f0190ab5a78ecb3 Mon Sep 17 00:00:00 2001 From: Zhipeng Xie Date: Thu, 12 Mar 2020 06:56:21 -0400 Subject: [PATCH 20/23] kpatch-build: add compile flag -fno-reorder-functions Sometimes function foo with static variables can be put in .text.foo section in original binary and be put in .text.unlikely.foo section in patched binary. This will result in "reference to static local variable xxx in foo was removed" problem because the .text.foo section can not be correlated to .text.unlikely.foo section by create-diff-object. gcc just put the function in .text.unlikely.xxx section,the symbol name doesn't change which is different with other optimization such as ".constprop/.isra/.part". So disable the optimization with -fno-reorder-functions just make sure the function is placed in .text.xxx section, kernel can still find the symbol name to patch or relocate. Signed-off-by: Zhipeng Xie --- kpatch-build/kpatch-build | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kpatch-build/kpatch-build b/kpatch-build/kpatch-build index de448dc..ad7ab71 100755 --- a/kpatch-build/kpatch-build +++ b/kpatch-build/kpatch-build @@ -887,7 +887,7 @@ if [[ "$ARCH" = "ppc64le" ]]; then ARCH_KCFLAGS="-mcmodel=large -fplugin=$PLUGINDIR/ppc64le-plugin.so" fi -export KCFLAGS="-I$DATADIR/patch -ffunction-sections -fdata-sections \ +export KCFLAGS="-I$DATADIR/patch -ffunction-sections -fdata-sections -fno-reorder-functions\ $ARCH_KCFLAGS $DEBUG_KCFLAGS ${GCC_ADD_OPTION}" echo "Reading special section data" -- 2.18.1