kpatch: fix two issues

kpatch: update sympos for duplicate symbols in vmlinux
create-diff-object: fix segment fault when sec2->rela is NULL

Signed-off-by: Zhipeng Xie <xiezhipeng1@huawei.com>

0030-kpatch-update-sympos-for-duplicate-symbols-in-vmlinu.patch

@@ -0,0 +1,104 @@
+From 8f5c1ff32fcc519bf061f68a481116f622b9cef8 Mon Sep 17 00:00:00 2001
+From: Zhipeng Xie <xiezhipeng1@huawei.com>
+Date: Fri, 10 Sep 2021 04:34:40 -0400
+Subject: [PATCH] kpatch: update sympos for duplicate symbols in vmlinux
+
+kallsyms in vmlinux is sorted by address, so symbol order
+in vmlinux is different from /proc/kallsyms, update sympos
+when patching duplicate symbol function.
+
+Signed-off-by: Zhipeng Xie <xiezhipeng1@huawei.com>
+Signed-off-by: hubin57 <hubin57@huawei.com>
+---
+ kpatch-build/create-diff-object.c | 26 ++++++--------------------
+ kpatch-build/lookup.c             | 24 ++++++++++++++++++++++++
+ kpatch-build/lookup.h             |  2 ++
+ 3 files changed, 32 insertions(+), 20 deletions(-)
+
+diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
+index afd5e3b..ff2b0e4 100644
+--- a/kpatch-build/create-diff-object.c
++++ b/kpatch-build/create-diff-object.c
+@@ -2813,26 +2813,12 @@ static void kpatch_create_patches_sections(struct kpatch_elf *kelf,
+ 			funcs[index].new_size = sym->sym.st_size;
+ 			funcs[index].sympos = result.pos;
+ 			if (lookup_is_duplicate_symbol(table, sym->name, objname, result.pos)) {
+-				struct lookup_refsym refsym;
+-				long offset;
+-
+-				if (lookup_ref_symbol_offset(table, sym->name, &refsym,
+-							objname, &offset))
+-					ERROR("unresolvable ambiguity on symbol %s\n", sym->name);
+-
+-				funcs[index].ref_offset = offset;
+-
+-				/*
+-				 * Add a relocation that will populate
+-				 * the funcs[index].ref_name field.
+-				 */
+-				ALLOC_LINK(rela, &relasec->relas);
+-				rela->sym = strsym;
+-				rela->type = absolute_rela_type;
+-				rela->addend = offset_of_string(&kelf->strings, refsym.name);
+-				rela->offset = (unsigned int)(index * sizeof(*funcs) +
+-					offsetof(struct kpatch_patch_func, ref_name));
+-
++				if (!strcmp(objname, "vmlinux")) {
++					result.pos = get_vmlinux_duplicate_symbol_pos(table, sym->name, result.value);
++					log_debug("update %s sympos from %ld to %ld\n",
++							sym->name, funcs[index].sympos, result.pos);
++					funcs[index].sympos = result.pos;
++				}
+ 			}
+ 
+ 
+diff --git a/kpatch-build/lookup.c b/kpatch-build/lookup.c
+index 888bcc9..aa8527d 100644
+--- a/kpatch-build/lookup.c
++++ b/kpatch-build/lookup.c
+@@ -526,6 +526,30 @@ int lookup_global_symbol(struct lookup_table *table, char *name,
+ 	return 1;
+ }
+ 
++/*
++ * In case sometimes the sympos of duplicate symbols are different in vmlinux and 
++ * /proc/kallsyms, and causes lookup_local_symbol to save wrong sympos in result, 
++ * this function returns correct sympos of the symbol, by comparing
++ * address value with the symbol in vmlinux symbol table.
++ */
++unsigned long get_vmlinux_duplicate_symbol_pos(struct lookup_table *table, 
++                                               char *name, unsigned long value)
++{
++	struct object_symbol *sym;
++	unsigned long pos = 1;
++	int i;
++
++	for_each_obj_symbol(i, sym, table) {
++		if (strcmp(sym->name, name))
++			continue;
++
++		if (sym->value < value)
++			pos++;
++	}
++
++	return pos;
++}
++
+ int lookup_is_exported_symbol(struct lookup_table *table, char *name)
+ {
+ 	struct export_symbol *sym, *match = NULL;
+diff --git a/kpatch-build/lookup.h b/kpatch-build/lookup.h
+index daeea73..c745366 100644
+--- a/kpatch-build/lookup.h
++++ b/kpatch-build/lookup.h
+@@ -37,5 +37,7 @@ int lookup_is_duplicate_symbol(struct lookup_table *table, char *name,
+ int lookup_ref_symbol_offset(struct lookup_table *table, char *name,
+ 		struct lookup_refsym *refsym, char *objname,
+ 			 long *offset);
++unsigned long get_vmlinux_duplicate_symbol_pos(struct lookup_table *table, char *name,
++                         unsigned long value);
+ 
+ #endif /* _LOOKUP_H_ */
+-- 
+2.27.0
+

0031-create-diff-object-fix-segment-fault-when-sec2-rela-.patch

@@ -0,0 +1,30 @@
+From 8d1e6f4cfe3fc7007f17e0f01e7ec8aa71e18cae Mon Sep 17 00:00:00 2001
+From: Zhipeng Xie <xiezhipeng1@huawei.com>
+Date: Fri, 17 Sep 2021 10:22:24 +0800
+Subject: [PATCH] create-diff-object: fix segment fault when sec2->rela is NULL
+
+when patched section has no rela section, we meet segment fault in
+__kpatch_correlate_section. add sec2->rela check to fix it.
+
+Signed-off-by: Zhipeng Xie <xiezhipeng1@huawei.com>
+Signed-off-by: hubin57 <hubin57@huawei.com>
+---
+ kpatch-build/create-diff-object.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
+index ff2b0e4..2159cf0 100644
+--- a/kpatch-build/create-diff-object.c
++++ b/kpatch-build/create-diff-object.c
+@@ -916,7 +916,7 @@ static void kpatch_correlate_section(struct section *sec1, struct section *sec2)
+ 		__kpatch_correlate_section(sec1->base, sec2->base);
+ 		sec1 = sec1->base;
+ 		sec2 = sec2->base;
+-	} else if (sec1->rela) {
++	} else if (sec1->rela && sec2->rela) {
+ 		__kpatch_correlate_section(sec1->rela, sec2->rela);
+ 	}
+ 
+-- 
+2.27.0
+

kpatch.spec

@@ -1,7 +1,7 @@
 Name:           kpatch
 Epoch:          1
 Version:        0.9.1
-Release:        17
+Release:        18
 Summary:        A Linux dynamic kernel patching infrastructure
 
 License:        GPLv2
@@ -41,6 +41,8 @@ Patch0026:0026-support-remove-static-variables-using-KPATCH_IGNORE_.patch
 Patch0027:0027-create-build-diff-support-for-.cold-functions-with-n.patch
 Patch0028:0028-lookup-Add-__UNIQUE_ID_-to-maybe_discarded_sym-list.patch
 Patch0029:0029-create-diff-object-error-on-detect-new-changed-ALTIN.patch
+Patch0030:0030-kpatch-update-sympos-for-duplicate-symbols-in-vmlinu.patch
+Patch0031:0031-create-diff-object-fix-segment-fault-when-sec2-rela-.patch
 
 BuildRequires:  gcc elfutils-libelf-devel kernel-devel git
 Requires:       bc make gcc patch bison flex openssl-devel
@@ -101,6 +103,13 @@ popd
 %{_mandir}/man1/*.1.gz
 
 %changelog
+* Tue Sep 28 2021 Zhipeng Xie<xiezhipeng1@huawei.com> -1:0.9.1-18
+- Type:bugfix
+- ID:NA
+- SUG:NA
+- DESC:kpatch: update sympos for duplicate symbols in vmlinux
+       create-diff-object: fix segment fault when sec2->rela is NULL
+
 * Tue Sep 28 2021 Bin Hu<hubin57@huawei.com> -1:0.9.1-17
 - Type:bugfix
 - ID:NA