lkml.org 
[lkml]   [2011]   [May]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH tip/core/rcu 1/3] rcu: get rid of signed overflow in check_cpu_stall()
Date
Signed integer overflow is undefined by the C standard, so move
calculations to unsigned.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcutree.c | 13 ++++++++-----
1 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 78923a5..b2fe2a2 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -581,21 +581,24 @@ static void print_cpu_stall(struct rcu_state *rsp)

static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
{
- long delta;
+ unsigned long j;
+ unsigned long js;
struct rcu_node *rnp;

if (rcu_cpu_stall_suppress)
return;
- delta = jiffies - ACCESS_ONCE(rsp->jiffies_stall);
+ j = ACCESS_ONCE(jiffies);
+ js = ACCESS_ONCE(rsp->jiffies_stall);
rnp = rdp->mynode;
- if ((ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && delta >= 0) {
+ if ((ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && ULONG_CMP_GE(j, js)) {

/* We haven't checked in, so go dump stack. */
print_cpu_stall(rsp);

- } else if (rcu_gp_in_progress(rsp) && delta >= RCU_STALL_RAT_DELAY) {
+ } else if (rcu_gp_in_progress(rsp) &&
+ ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY)) {

- /* They had two time units to dump stack, so complain. */
+ /* They had a few time units to dump stack, so complain. */
print_other_cpu_stall(rsp);
}
}
--
1.7.3.2


\
 
 \ /
  Last update: 2011-05-08 15:37    [W:0.030 / U:0.252 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site