When runs in perf mode, the driver always enables the contextID tracing. This can lead to confusion if the program runs in non-root PID namespace and potentially leak kernel information.
When programs running in perf mode, this patch changes to only enable contextID tracing for root PID namespace.
Signed-off-by: Leo Yan leo.yan@linaro.org --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index e24252eaf8e4..6e614bfb38c6 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -615,7 +615,9 @@ static int etm4_parse_event_config(struct coresight_device *csdev, config->cfg |= BIT(11); }
- if (attr->config & BIT(ETM_OPT_CTXTID)) + /* Only trace contextID when runs in root PID namespace */ + if ((attr->config & BIT(ETM_OPT_CTXTID)) && + (task_active_pid_ns(current) == &init_pid_ns)) /* bit[6], Context ID tracing bit */ config->cfg |= BIT(ETM4_CFG_BIT_CTXTID);
@@ -629,7 +631,11 @@ static int etm4_parse_event_config(struct coresight_device *csdev, ret = -EINVAL; goto out; } - config->cfg |= BIT(ETM4_CFG_BIT_VMID) | BIT(ETM4_CFG_BIT_VMID_OPT); + + /* Only trace virtual contextID when runs in root PID namespace */ + if (task_active_pid_ns(current) == &init_pid_ns) + config->cfg |= BIT(ETM4_CFG_BIT_VMID) | + BIT(ETM4_CFG_BIT_VMID_OPT); }
/* return stack - enable if selected and supported */