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tracing: Protect tracer flags with trace_types_lock

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Seems that the tracer flags have never been protected from
synchronous writes. Luckily, admins don't usually modify the
tracing flags via two different tasks. But if scripts were to
be used to modify them, then they could get corrupted.

Move the trace_types_lock that protects against tracers changing
to also protect the flags being set.

Cc: stable@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2013-03-14 13:50:56 -04:00 committed by Steven Rostedt
parent 740466bc89
commit 69d34da298
1 changed files with 8 additions and 4 deletions
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12
kernel/trace/trace.c
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@ -2916,6 +2916,8 @@ static int trace_set_options(char *option)
cmp += 2;
}
mutex_lock(&trace_types_lock);
for (i = 0; trace_options[i]; i++) {
if (strcmp(cmp, trace_options[i]) == 0) {
set_tracer_flags(1 << i, !neg);
@ -2924,11 +2926,10 @@ static int trace_set_options(char *option)
}
/* If no option could be set, test the specific tracer options */
if (!trace_options[i]) {
mutex_lock(&trace_types_lock);
if (!trace_options[i])
ret = set_tracer_option(current_trace, cmp, neg);
mutex_unlock(&trace_types_lock);
}
mutex_unlock(&trace_types_lock);
return ret;
}
@ -4781,7 +4782,10 @@ trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
if (val != 0 && val != 1)
return -EINVAL;
mutex_lock(&trace_types_lock);
set_tracer_flags(1 << index, val);
mutex_unlock(&trace_types_lock);
*ppos += cnt;