This is a note to let you know that I've just added the patch titled
livepatch: add module locking around kallsyms calls
to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
livepatch-add-module-locking-around-kallsyms-calls.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9a1bd63cdae4b623494c4ebaf723a91c35ec49fb Mon Sep 17 00:00:00 2001
From: Miroslav Benes <mbenes@xxxxxxx>
Date: Mon, 1 Jun 2015 17:48:37 +0200
Subject: livepatch: add module locking around kallsyms calls
From: Miroslav Benes <mbenes@xxxxxxx>
commit 9a1bd63cdae4b623494c4ebaf723a91c35ec49fb upstream.
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@xxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/livepatch/core.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -179,7 +179,9 @@ static int klp_find_object_symbol(const
.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(con
.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);
+
+ if (!ret) {
+ pr_err("symbol '%s' not found at specified address 0x%016lx, kernel mismatch?\n",
+ name, addr);
+ return -EINVAL;
+ }
- 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,
Patches currently in stable-queue which might be from mbenes@xxxxxxx are
queue-4.1/livepatch-add-module-locking-around-kallsyms-calls.patch
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