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
...@@ -46,6 +46,11 @@ ...@@ -46,6 +46,11 @@
#include "mce-internal.h" #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 #define CREATE_TRACE_POINTS
#include <trace/events/mce.h> #include <trace/events/mce.h>
...@@ -158,7 +163,7 @@ void mce_log(struct mce *mce) ...@@ -158,7 +163,7 @@ void mce_log(struct mce *mce)
mce->finished = 0; mce->finished = 0;
wmb(); wmb();
for (;;) { for (;;) {
entry = rcu_dereference(mcelog.next); entry = rcu_dereference_check_mce(mcelog.next);
for (;;) { for (;;) {
/* /*
* When the buffer fills up discard new entries. * 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, ...@@ -1500,7 +1505,7 @@ static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize,
return -ENOMEM; return -ENOMEM;
mutex_lock(&mce_read_mutex); mutex_lock(&mce_read_mutex);
next = rcu_dereference(mcelog.next); next = rcu_dereference_check_mce(mcelog.next);
/* Only supports full reads right now */ /* Only supports full reads right now */
if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) { if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) {
...@@ -1565,7 +1570,7 @@ timeout: ...@@ -1565,7 +1570,7 @@ timeout:
static unsigned int mce_poll(struct file *file, poll_table *wait) static unsigned int mce_poll(struct file *file, poll_table *wait)
{ {
poll_wait(file, &mce_wait, wait); poll_wait(file, &mce_wait, wait);
if (rcu_dereference(mcelog.next)) if (rcu_dereference_check_mce(mcelog.next))
return POLLIN | POLLRDNORM; return POLLIN | POLLRDNORM;
return 0; return 0;
} }
......
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