From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Mathieu Poirier <mathieu.poirier@linaro.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@linaro.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>
Cc: coresight@lists.linaro.org, Stephen Boyd <swboyd@chromium.org>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Subject: [PATCHv2 3/4] coresight: etb10: Fix possible NULL ptr dereference in etb_enable_perf()
Date: Thu, 22 Oct 2020 16:27:53 +0530 [thread overview]
Message-ID: <8c649ac9c3119edb1fff218c972909a48cdda122.1603363729.git.saiprakash.ranjan@codeaurora.org> (raw)
In-Reply-To: <cover.1603363729.git.saiprakash.ranjan@codeaurora.org>
There was a report of NULL pointer dereference in ETF enable
path for perf CS mode with PID monitoring. It is almost 100%
reproducible when the process to monitor is something very
active such as chrome and with ETF as the sink.
But code path shows that ETB has a similar path as ETF, so
there could be possible NULL pointer dereference crash in
ETB as well. Currently in a bid to find the pid, the owner
is dereferenced via task_pid_nr() call in etb_enable_perf()
and with owner being NULL, we can get a NULL pointer
dereference, so have a similar change as ETF where we cache
PID in alloc_buffer() callback which is called as the part of
etm_setup_aux(). This will reduce the task_pid_nr() function
call overheads as well. In addition to this, add a check to
validate event->owner before dereferencing it to fix any
possible NULL pointer dereference crashes and check for
kernel events.
Fixes: 75d7dbd38824 ("coresight: etb10: Add support for CPU-wide trace scenarios")
Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
---
drivers/hwtracing/coresight/coresight-etb10.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 248cc82c838e..9d2f1ab0e29e 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -176,6 +176,7 @@ static int etb_enable_perf(struct coresight_device *csdev, void *data)
unsigned long flags;
struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
struct perf_output_handle *handle = data;
+ struct cs_buffers *buf = etm_perf_sink_config(handle);
spin_lock_irqsave(&drvdata->spinlock, flags);
@@ -186,7 +187,7 @@ static int etb_enable_perf(struct coresight_device *csdev, void *data)
}
/* Get a handle on the pid of the process to monitor */
- pid = task_pid_nr(handle->event->owner);
+ pid = buf->pid;
if (drvdata->pid != -1 && drvdata->pid != pid) {
ret = -EBUSY;
@@ -376,6 +377,10 @@ static void *etb_alloc_buffer(struct coresight_device *csdev,
{
int node;
struct cs_buffers *buf;
+ struct task_struct *task = READ_ONCE(event->owner);
+
+ if (!task || is_kernel_event(event))
+ return NULL;
node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
@@ -383,6 +388,7 @@ static void *etb_alloc_buffer(struct coresight_device *csdev,
if (!buf)
return NULL;
+ buf->pid = task_pid_nr(task);
buf->snapshot = overwrite;
buf->nr_pages = nr_pages;
buf->data_pages = pages;
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation
next prev parent reply other threads:[~2020-10-22 10:58 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 10:57 [PATCHv2 0/4] coresight: etf/etb10/etr: Fix NULL pointer dereference crashes Sai Prakash Ranjan
2020-10-22 10:57 ` [PATCHv2 1/4] perf/core: Export is_kernel_event() Sai Prakash Ranjan
2020-10-22 10:57 ` [PATCHv2 2/4] coresight: tmc-etf: Fix NULL ptr dereference in tmc_enable_etf_sink_perf() Sai Prakash Ranjan
2020-10-22 11:32 ` Peter Zijlstra
2020-10-22 12:49 ` Sai Prakash Ranjan
2020-10-22 13:34 ` Peter Zijlstra
2020-10-22 14:23 ` Sai Prakash Ranjan
2020-10-22 13:30 ` Suzuki Poulose
2020-10-22 15:06 ` Peter Zijlstra
2020-10-22 15:32 ` Suzuki Poulose
2020-10-22 21:20 ` Mathieu Poirier
2020-10-23 7:39 ` Peter Zijlstra
2020-10-23 8:49 ` Suzuki Poulose
2020-10-23 9:23 ` Peter Zijlstra
2020-10-23 10:49 ` Suzuki Poulose
2020-10-23 9:41 ` Peter Zijlstra
2020-10-23 10:34 ` Suzuki Poulose
2020-10-23 10:54 ` Peter Zijlstra
2020-10-23 12:56 ` Suzuki Poulose
2020-10-23 13:16 ` Peter Zijlstra
2020-10-23 13:29 ` Suzuki Poulose
2020-10-23 13:44 ` Peter Zijlstra
2020-10-23 20:37 ` Mathieu Poirier
2020-10-30 7:59 ` Sai Prakash Ranjan
2020-10-30 16:48 ` Mathieu Poirier
2020-10-30 17:26 ` Sai Prakash Ranjan
2020-11-04 17:03 ` Mathieu Poirier
2020-10-22 10:57 ` Sai Prakash Ranjan [this message]
2020-10-22 10:57 ` [PATCHv2 4/4] coresight: tmc-etr: Fix possible NULL ptr dereference in get_perf_etr_buf_cpu_wide() Sai Prakash Ranjan
2020-10-22 11:10 ` [PATCHv2 0/4] coresight: etf/etb10/etr: Fix NULL pointer dereference crashes Sai Prakash Ranjan
2020-10-22 11:23 ` Sai Prakash Ranjan
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