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Subject[PATCH 1/4] tracing: fix a typo in tracing_cpumask_write()
It's tracing_cpumask_new that should be kfree()ed.

This causes tracing_cpumask to be freed due to the typo:

# echo z > tracing_cpumask
bash: echo: write error: Invalid argument
And subsequent reads/writes to tracing_cpuamsk will access this
already-freed tracing_cpumask, thus may lead to crash.

[ Impact: fix leak and crash when writing invalid val to tracing_cpumask ]

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
kernel/trace/trace.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8acd9b8..7355a38 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2191,11 +2191,12 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
return -ENOMEM;

- mutex_lock(&tracing_cpumask_update_lock);
err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
if (err)
goto err_unlock;

+ mutex_lock(&tracing_cpumask_update_lock);
+
local_irq_disable();
__raw_spin_lock(&ftrace_max_lock);
for_each_tracing_cpu(cpu) {
@@ -2223,8 +2224,7 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
return count;

err_unlock:
- mutex_unlock(&tracing_cpumask_update_lock);
- free_cpumask_var(tracing_cpumask);
+ free_cpumask_var(tracing_cpumask_new);

return err;
}
--
1.5.4.rc3


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