Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f56e8a07 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Ingo Molnar
Browse files

x86/mce: Fix RCU lockdep splats 



Create an rcu_dereference_check_mce() that checks for RCU-sched
read side and mce_read_mutex being held on update side.  Replace
uses of rcu_dereference() in arch/x86/kernel/cpu/mcheck/mce.c
with this new macro.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1267830207-9474-3-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 007b0924

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

+8 −3
Original line number Diff line number Diff line
@@ -46,6 +46,11 @@ 


#include "mce-internal.h"



#define rcu_dereference_check_mce(p) \

	rcu_dereference_check((p), \

			      rcu_read_lock_sched_held() || \

			      lockdep_is_held(&mce_read_mutex))



#define CREATE_TRACE_POINTS

#include <trace/events/mce.h>
@@ -158,7 +163,7 @@ void mce_log(struct mce *mce) 
	mce->finished = 0;

	wmb();

	for (;;) {

		entry = rcu_dereference(mcelog.next);

		entry = rcu_dereference_check_mce(mcelog.next);

		for (;;) {

			/*

			 * When the buffer fills up discard new entries.
@@ -1500,7 +1505,7 @@ static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize, 
		return -ENOMEM;



	mutex_lock(&mce_read_mutex);

	next = rcu_dereference(mcelog.next);

	next = rcu_dereference_check_mce(mcelog.next);



	/* Only supports full reads right now */

	if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) {
@@ -1565,7 +1570,7 @@ static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize, 
static unsigned int mce_poll(struct file *file, poll_table *wait)

{

	poll_wait(file, &mce_wait, wait);

	if (rcu_dereference(mcelog.next))

	if (rcu_dereference_check_mce(mcelog.next))

		return POLLIN | POLLRDNORM;

	return 0;

}