Commit a3125494 authored Apr 06, 2016 by Tony Luck Committed by Ingo Molnar Apr 13, 2016

x86/mce: Avoid using object after free in genpool



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@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Cc: Gong Chen <gong.chen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/0205920@agluck-desk.sc.intel.com
Link: http://lkml.kernel.org/r/1459929916-12852-4-git-send-email-bp@alien8.de


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent f87e0434

arch/x86/kernel/cpu/mcheck/mce-genpool.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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));