| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.5 005/200] x86/mce: Avoid using object after free in genpool | Date | Mon, 2 May 2016 17:10:04 -0700 |
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4.5-stable review patch. If anyone has any objections, please let me know.
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From: Tony Luck <tony.luck@intel.com>
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@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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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