From 74f78de8bd7f97f4129320f944024ffaa4317c9e Mon Sep 17 00:00:00 2001 From: Zhipeng Xie Date: Thu, 12 Mar 2020 06:56:21 -0400 Subject: [PATCH 17/37] 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 a5168f5..a73bd1b 100755 --- a/kpatch-build/kpatch-build +++ b/kpatch-build/kpatch-build @@ -975,7 +975,7 @@ if [[ "$ARCH" = "s390x" ]]; then ARCH_KCFLAGS="-mno-pic-data-is-text-relative -fno-section-anchors" fi -export KCFLAGS="-I$DATADIR/patch -ffunction-sections -fdata-sections \ +export KCFLAGS="-I$DATADIR/patch -ffunction-sections -fdata-sections -fno-reorder-functions \ $ARCH_KCFLAGS $DEBUG_KCFLAGS" echo "Reading special section data" -- 2.33.0