diff options
| author | David Woodhouse <David.Woodhouse@intel.com> | 2010-02-26 19:04:15 +0000 |
|---|---|---|
| committer | David Woodhouse <David.Woodhouse@intel.com> | 2010-02-26 19:06:24 +0000 |
| commit | a7790532f5b7358c33a6b1834dc2b318de209f31 (patch) | |
| tree | 0ceb9e24b3f54cb5c8453fb5a218e2a94a0f1cce /kernel/trace/trace_stack.c | |
| parent | 2764fb4244cc1bc08df3667924ca4a972e90ac70 (diff) | |
| parent | 60b341b778cc2929df16c0a504c91621b3c6a4ad (diff) | |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
The SmartMedia FTL code depends on new kfifo bits from 2.6.33
Diffstat (limited to 'kernel/trace/trace_stack.c')
| -rw-r--r-- | kernel/trace/trace_stack.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 678a5120ee3..f4bc9b27de5 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -157,6 +157,7 @@ stack_max_size_write(struct file *filp, const char __user *ubuf, unsigned long val, flags; char buf[64]; int ret; + int cpu; if (count >= sizeof(buf)) return -EINVAL; @@ -171,9 +172,20 @@ stack_max_size_write(struct file *filp, const char __user *ubuf, return ret; local_irq_save(flags); + + /* + * In case we trace inside arch_spin_lock() or after (NMI), + * we will cause circular lock, so we also need to increase + * the percpu trace_active here. + */ + cpu = smp_processor_id(); + per_cpu(trace_active, cpu)++; + arch_spin_lock(&max_stack_lock); *ptr = val; arch_spin_unlock(&max_stack_lock); + + per_cpu(trace_active, cpu)--; local_irq_restore(flags); return count; @@ -206,7 +218,13 @@ t_next(struct seq_file *m, void *v, loff_t *pos) static void *t_start(struct seq_file *m, loff_t *pos) { + int cpu; + local_irq_disable(); + + cpu = smp_processor_id(); + per_cpu(trace_active, cpu)++; + arch_spin_lock(&max_stack_lock); if (*pos == 0) @@ -217,7 +235,13 @@ static void *t_start(struct seq_file *m, loff_t *pos) static void t_stop(struct seq_file *m, void *p) { + int cpu; + arch_spin_unlock(&max_stack_lock); + + cpu = smp_processor_id(); + per_cpu(trace_active, cpu)--; + local_irq_enable(); } |