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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-06-18 09:18:31 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-07-09 09:15:04 -0700 |
| commit | bc1dce514e9b29b64df28a533015885862f47814 (patch) | |
| tree | 72977f4949a34fa20736dfdd69c6f740ae086d37 | |
| parent | c0f489d2c6fec8994c642c2ec925eb858727dc7b (diff) | |
| download | linux-bc1dce514e9b29b64df28a533015885862f47814.tar.gz linux-bc1dce514e9b29b64df28a533015885862f47814.tar.bz2 linux-bc1dce514e9b29b64df28a533015885862f47814.zip | |
rcu: Don't use NMIs to dump other CPUs' stacks
Although NMI-based stack dumps are in principle more accurate, they are
also more likely to trigger deadlocks. This commit therefore replaces
all uses of trigger_all_cpu_backtrace() with rcu_dump_cpu_stacks(), so
that the CPU detecting an RCU CPU stall does the stack dumping.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
| -rw-r--r-- | kernel/rcu/tree.c | 10 |
1 files changed, 3 insertions, 7 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 3f93033d3c61..8f3e4d43d736 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1013,10 +1013,7 @@ static void record_gp_stall_check_time(struct rcu_state *rsp) } /* - * Dump stacks of all tasks running on stalled CPUs. This is a fallback - * for architectures that do not implement trigger_all_cpu_backtrace(). - * The NMI-triggered stack traces are more accurate because they are - * printed by the target CPU. + * Dump stacks of all tasks running on stalled CPUs. */ static void rcu_dump_cpu_stacks(struct rcu_state *rsp) { @@ -1094,7 +1091,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp) (long)rsp->gpnum, (long)rsp->completed, totqlen); if (ndetected == 0) pr_err("INFO: Stall ended before state dump start\n"); - else if (!trigger_all_cpu_backtrace()) + else rcu_dump_cpu_stacks(rsp); /* Complain about tasks blocking the grace period. */ @@ -1125,8 +1122,7 @@ static void print_cpu_stall(struct rcu_state *rsp) pr_cont(" (t=%lu jiffies g=%ld c=%ld q=%lu)\n", jiffies - rsp->gp_start, (long)rsp->gpnum, (long)rsp->completed, totqlen); - if (!trigger_all_cpu_backtrace()) - dump_stack(); + rcu_dump_cpu_stacks(rsp); raw_spin_lock_irqsave(&rnp->lock, flags); if (ULONG_CMP_GE(jiffies, ACCESS_ONCE(rsp->jiffies_stall))) |