This is a note to let you know that I've just added the patch titled
x86/mce: Avoid using object after free in genpool
to the 4.4-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:
x86-mce-avoid-using-object-after-free-in-genpool.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a3125494cff084b098c80bb36fbe2061ffed9d52 Mon Sep 17 00:00:00 2001
From: Tony Luck <tony.luck@xxxxxxxxx>
Date: Wed, 6 Apr 2016 10:05:16 +0200
Subject: x86/mce: Avoid using object after free in genpool
From: Tony Luck <tony.luck@xxxxxxxxx>
commit a3125494cff084b098c80bb36fbe2061ffed9d52 upstream.
When we loop over all queued machine check error records to pass them
to the registered notifiers we use llist_for_each_entry(). But the loop
calls gen_pool_free() for the entry in the body of the loop - and then
the iterator looks at node->next after the free.
Use llist_for_each_entry_safe() instead.
Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Gong Chen <gong.chen@xxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-edac <linux-edac@xxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/0205920@xxxxxxxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1459929916-12852-4-git-send-email-bp@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/mcheck/mce-genpool.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/cpu/mcheck/mce-genpool.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-genpool.c
@@ -29,7 +29,7 @@ static char gen_pool_buf[MCE_POOLSZ];
void mce_gen_pool_process(void)
{
struct llist_node *head;
- struct mce_evt_llist *node;
+ struct mce_evt_llist *node, *tmp;
struct mce *mce;
head = llist_del_all(&mce_event_llist);
@@ -37,7 +37,7 @@ void mce_gen_pool_process(void)
return;
head = llist_reverse_order(head);
- llist_for_each_entry(node, head, llnode) {
+ llist_for_each_entry_safe(node, tmp, head, llnode) {
mce = &node->mce;
atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));
Patches currently in stable-queue which might be from tony.luck@xxxxxxxxx are
queue-4.4/x86-mce-avoid-using-object-after-free-in-genpool.patch
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