From 2b92531df29bda1abea88235fbdf952c80d9d469 Mon Sep 17 00:00:00 2001
From: Seth Jennings <sjenning@redhat.com>
Date: Thu, 15 May 2014 15:22:52 -0500
Subject: [PATCH] fix list corruption in special section handlers
The kpatch_regenerate_* functions use a local list_head to construct the
new list. While the local list_head is copied to the sec->relas after
it is built, the neighboring nodes in the list are not updated, leading
to list corruption.
This commit uses list_replace() which updates the neighbor nodes properly.
Regression introduced by PR #117 5d36dd1.
Fixes #185.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
---
kpatch-build/create-diff-object.c | 6 +++---
kpatch-build/list.h | 16 ++++++++++++++++
2 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
index fbce2a0..cd58730 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -1029,7 +1029,7 @@ void kpatch_regenerate_bug_table_rela_section(struct kpatch_elf *kelf)
}
/* overwrite with new relas list */
- sec->relas = newrelas;
+ list_replace(&newrelas, &sec->relas);
/* include both rela and text sections */
sec->include = 1;
@@ -1076,7 +1076,7 @@ void kpatch_regenerate_smp_locks_sections(struct kpatch_elf *kelf)
}
/* overwrite with new relas list */
- sec->relas = newrelas;
+ list_replace(&newrelas, &sec->relas);
/* include both rela and text sections */
sec->include = 1;
@@ -1141,7 +1141,7 @@ void kpatch_regenerate_parainstructions_sections(struct kpatch_elf *kelf)
}
/* overwrite with new relas table */
- sec->relas = newrelas;
+ list_replace(&newrelas, &sec->relas);
/* mark sections for inclusion */
sec->include = 1;
diff --git a/kpatch-build/list.h b/kpatch-build/list.h
index 7da8453..825fd95 100644
--- a/kpatch-build/list.h
+++ b/kpatch-build/list.h
@@ -142,6 +142,22 @@ static inline void list_del(struct list_head *entry)
entry->prev = LIST_POISON2;
}
+/**
+ * list_replace - replace old entry by new one
+ * @old : the element to be replaced
+ * @new : the new element to insert
+ *
+ * If @old was empty, it will be overwritten.
+ */
+static inline void list_replace(struct list_head *old,
+ struct list_head *new)
+{
+ new->next = old->next;
+ new->next->prev = new;
+ new->prev = old->prev;
+ new->prev->next = new;
+}
+
#define list_entry(ptr, type, member) \
container_of(ptr, type, member)