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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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