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authorMiroslav Benes <mbenes@suse.cz>2015-06-01 17:48:37 +0200
committerJiri Kosina <jkosina@suse.cz>2015-06-02 22:54:38 +0200
commit9a1bd63cdae4b623494c4ebaf723a91c35ec49fb (patch)
treeebb05d25771b64db46b476686c70d7691e6cb692 /kernel/livepatch
parent9497d7380b9c450830190c75aa43b25c278bb1f9 (diff)
downloadlinux-sh-9a1bd63cdae4b623494c4ebaf723a91c35ec49fb.tar.gz
livepatch: add module locking around kallsyms calls
The list of loaded modules is walked through in module_kallsyms_on_each_symbol (called by kallsyms_on_each_symbol). The module_mutex lock should be acquired to prevent potential corruptions in the list. This was uncovered with new lockdep asserts in module code introduced by the commit 0be964be0d45 ("module: Sanitize RCU usage and locking") in recent next- trees. Signed-off-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'kernel/livepatch')
-rw-r--r--kernel/livepatch/core.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 284e2691e380..9ec555732f1a 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -179,7 +179,9 @@ static int klp_find_object_symbol(const char *objname, const char *name,
.count = 0
};
+ mutex_lock(&module_mutex);
kallsyms_on_each_symbol(klp_find_callback, &args);
+ mutex_unlock(&module_mutex);
if (args.count == 0)
pr_err("symbol '%s' not found in symbol table\n", name);
@@ -219,13 +221,19 @@ static int klp_verify_vmlinux_symbol(const char *name, unsigned long addr)
.name = name,
.addr = addr,
};
+ int ret;
- if (kallsyms_on_each_symbol(klp_verify_callback, &args))
- return 0;
+ mutex_lock(&module_mutex);
+ ret = kallsyms_on_each_symbol(klp_verify_callback, &args);
+ mutex_unlock(&module_mutex);
- pr_err("symbol '%s' not found at specified address 0x%016lx, kernel mismatch?\n",
- name, addr);
- return -EINVAL;
+ if (!ret) {
+ pr_err("symbol '%s' not found at specified address 0x%016lx, kernel mismatch?\n",
+ name, addr);
+ return -EINVAL;
+ }
+
+ return 0;
}
static int klp_find_verify_func_addr(struct klp_object *obj,