4.5-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tony Luck <[email protected]>

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 <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: Gong Chen <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: linux-edac <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 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));


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