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tracing: Have tracing_max_latency inc the trace array ref count

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The tracing_max_latency file points to the trace_array max_latency field.
For an instance, if the file is opened and the instance is deleted,
reading or writing to the file will cause a use after free.

Up the ref count of the trace_array when tracing_max_latency is opened.

Link: https://lkml.kernel.org/r/20230907024803.666889383@goodmis.org
Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Fixes: 8530dec63e ("tracing: Add tracing_check_open_get_tr()")
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Google) 2023-09-06 22:47:13 -04:00
parent f5ca233e2e
commit 7d660c9b2b
1 changed files with 10 additions and 5 deletions
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15
kernel/trace/trace.c
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@ -1772,7 +1772,7 @@ static void trace_create_maxlat_file(struct trace_array *tr,
init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq); init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
tr->d_max_latency = trace_create_file("tracing_max_latency", tr->d_max_latency = trace_create_file("tracing_max_latency",
TRACE_MODE_WRITE, TRACE_MODE_WRITE,
d_tracer, &tr->max_latency, d_tracer, tr,
&tracing_max_lat_fops); &tracing_max_lat_fops);
} }
@ -1805,7 +1805,7 @@ void latency_fsnotify(struct trace_array *tr)
#define trace_create_maxlat_file(tr, d_tracer) \ #define trace_create_maxlat_file(tr, d_tracer) \
trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \ trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \
d_tracer, &tr->max_latency, &tracing_max_lat_fops) d_tracer, tr, &tracing_max_lat_fops)
#endif #endif
@ -6717,14 +6717,18 @@ static ssize_t
tracing_max_lat_read(struct file *filp, char __user *ubuf, tracing_max_lat_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos) size_t cnt, loff_t *ppos)
{ {
return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos); struct trace_array *tr = filp->private_data;
return tracing_nsecs_read(&tr->max_latency, ubuf, cnt, ppos);
} }
static ssize_t static ssize_t
tracing_max_lat_write(struct file *filp, const char __user *ubuf, tracing_max_lat_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos) size_t cnt, loff_t *ppos)
{ {
return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos); struct trace_array *tr = filp->private_data;
return tracing_nsecs_write(&tr->max_latency, ubuf, cnt, ppos);
} }
#endif #endif
@ -7778,10 +7782,11 @@ static const struct file_operations tracing_thresh_fops = {
#ifdef CONFIG_TRACER_MAX_TRACE #ifdef CONFIG_TRACER_MAX_TRACE
static const struct file_operations tracing_max_lat_fops = { static const struct file_operations tracing_max_lat_fops = {
.open = tracing_open_generic, .open = tracing_open_generic_tr,
.read = tracing_max_lat_read, .read = tracing_max_lat_read,
.write = tracing_max_lat_write, .write = tracing_max_lat_write,
.llseek = generic_file_llseek, .llseek = generic_file_llseek,
.release = tracing_release_generic_tr,
}; };
#endif #endif