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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2011-08-03 03:34:24 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2011-09-28 21:38:36 -0700
commit4627e240dfee4a0a46a58010b1b721b4ded1918f (patch)
tree807cc0618bc843800aa85fd6d20b4e9ee7adb74b /kernel/rcutree.c
parent6206ab9bab620fc0fbbed30ce20d145b0b3d1840 (diff)
downloadblackbird-op-linux-4627e240dfee4a0a46a58010b1b721b4ded1918f.tar.gz
blackbird-op-linux-4627e240dfee4a0a46a58010b1b721b4ded1918f.zip
rcu: Dump local stack if cannot dump all CPUs' stacks
The trigger_all_cpu_backtrace() function is a no-op in architectures that do not define arch_trigger_all_cpu_backtrace. On such architectures, RCU CPU stall warning messages contain no stack trace information, which makes debugging quite difficult. This commit therefore substitutes dump_stack() for architectures that do not define arch_trigger_all_cpu_backtrace, so that at least the local CPU's stack is dumped as part of the RCU CPU stall warning message. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcutree.c')
-rw-r--r--kernel/rcutree.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index ebd18e56947b..a07bf553e02a 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -583,7 +583,8 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
}
printk("} (detected by %d, t=%ld jiffies)\n",
smp_processor_id(), (long)(jiffies - rsp->gp_start));
- trigger_all_cpu_backtrace();
+ if (!trigger_all_cpu_backtrace())
+ dump_stack();
/* If so configured, complain about tasks blocking the grace period. */
@@ -604,7 +605,8 @@ static void print_cpu_stall(struct rcu_state *rsp)
*/
printk(KERN_ERR "INFO: %s detected stall on CPU %d (t=%lu jiffies)\n",
rsp->name, smp_processor_id(), jiffies - rsp->gp_start);
- trigger_all_cpu_backtrace();
+ if (!trigger_all_cpu_backtrace())
+ dump_stack();
raw_spin_lock_irqsave(&rnp->lock, flags);
if (ULONG_CMP_GE(jiffies, rsp->jiffies_stall))
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