The previous implementation limited the tracing capabilities when perf was run in the init PID namespace, making it impossible to trace applications in non-init PID namespaces.
This update improves the tracing process by verifying the event owner. This allows us to determine whether the user has the necessary permissions to trace the application.
Cc: stable@vger.kernel.org Fixes: aab473867fed ("coresight: etm4x: Don't trace PID for non-root PID namespace") Signed-off-by: Julien Meunier julien.meunier@nokia.com --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index bf01f01964cf..8365307b1aec 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -695,7 +695,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
/* Only trace contextID when runs in root PID namespace */ if ((attr->config & BIT(ETM_OPT_CTXTID)) && - task_is_in_init_pid_ns(current)) + task_is_in_init_pid_ns(event->owner)) /* bit[6], Context ID tracing bit */ config->cfg |= TRCCONFIGR_CID;
@@ -710,7 +710,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, goto out; } /* Only trace virtual contextID when runs in root PID namespace */ - if (task_is_in_init_pid_ns(current)) + if (task_is_in_init_pid_ns(event->owner)) config->cfg |= TRCCONFIGR_VMID | TRCCONFIGR_VMIDOPT; }
On 25/09/2024 14:13, Julien Meunier wrote:
The previous implementation limited the tracing capabilities when perf was run in the init PID namespace, making it impossible to trace applications in non-init PID namespaces.
This update improves the tracing process by verifying the event owner. This allows us to determine whether the user has the necessary permissions to trace the application.
Cc: stable@vger.kernel.org Fixes: aab473867fed ("coresight: etm4x: Don't trace PID for non-root PID namespace") Signed-off-by: Julien Meunier julien.meunier@nokia.com
Thanks for the fix, I will queue this for v6.13
Suzuki
drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index bf01f01964cf..8365307b1aec 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -695,7 +695,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, /* Only trace contextID when runs in root PID namespace */ if ((attr->config & BIT(ETM_OPT_CTXTID)) &&
task_is_in_init_pid_ns(current))
task_is_in_init_pid_ns(event->owner))@@ -710,7 +710,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, goto out; } /* Only trace virtual contextID when runs in root PID namespace */
if (task_is_in_init_pid_ns(current))
if (task_is_in_init_pid_ns(event->owner)) config->cfg |= TRCCONFIGR_VMID | TRCCONFIGR_VMIDOPT;
Hi Julien,
On Wed, Sep 25, 2024 at 03:13:56PM +0200, Julien Meunier wrote:
The previous implementation limited the tracing capabilities when perf was run in the init PID namespace, making it impossible to trace applications in non-init PID namespaces.
This update improves the tracing process by verifying the event owner. This allows us to determine whether the user has the necessary permissions to trace the application.
The original commit aab473867fed is not for constraint permission. It is about PID namespace mismatching issue.
E.g. Perf runs in non-root namespace, thus it records process info in the non-root PID namespace. On the other hand, Arm CoreSight traces PID for root namespace, as a result, it will lead mess when decoding.
With this change, I am not convinced that Arm CoreSight can trace PID for non-root PID namespace. Seems to me, the concerned issue is still existed - it might cause PID mismatching issue between hardware trace data and Perf's process info.
I think we need to check using the software context switch event. With more clear idea, I will get back at here.
Thanks, Leo
Cc: stable@vger.kernel.org Fixes: aab473867fed ("coresight: etm4x: Don't trace PID for non-root PID namespace") Signed-off-by: Julien Meunier julien.meunier@nokia.com
drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index bf01f01964cf..8365307b1aec 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -695,7 +695,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, /* Only trace contextID when runs in root PID namespace */ if ((attr->config & BIT(ETM_OPT_CTXTID)) &&
task_is_in_init_pid_ns(current))
task_is_in_init_pid_ns(event->owner))@@ -710,7 +710,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, goto out; } /* Only trace virtual contextID when runs in root PID namespace */
if (task_is_in_init_pid_ns(current))
if (task_is_in_init_pid_ns(event->owner)) config->cfg |= TRCCONFIGR_VMID | TRCCONFIGR_VMIDOPT;2.34.1
On 10/7/2024 9:05 PM, Leo Yan wrote:
Hi Julien,
On Wed, Sep 25, 2024 at 03:13:56PM +0200, Julien Meunier wrote:
The previous implementation limited the tracing capabilities when perf was run in the init PID namespace, making it impossible to trace applications in non-init PID namespaces.
This update improves the tracing process by verifying the event owner. This allows us to determine whether the user has the necessary permissions to trace the application.
The original commit aab473867fed is not for constraint permission. It is about PID namespace mismatching issue.
E.g. Perf runs in non-root namespace, thus it records process info in the non-root PID namespace. On the other hand, Arm CoreSight traces PID for root namespace, as a result, it will lead mess when decoding.
With this change, I am not convinced that Arm CoreSight can trace PID for non-root PID namespace. Seems to me, the concerned issue is still existed
- it might cause PID mismatching issue between hardware trace data and
Perf's process info.
I thought again and found I was wrong with above conclusion. This patch is a good fixing for the perf running in root namespace to profile programs in non-root namespace. Sorry for noise.
Maybe it is good to improve a bit comments to avoid confusion. See below.
[...]
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index bf01f01964cf..8365307b1aec 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -695,7 +695,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
/* Only trace contextID when runs in root PID namespace */
We can claim the requirement for the *tool* running in root PID namespae.
/* Only trace contextID when the tool runs in root PID namespace */
if ((attr->config & BIT(ETM_OPT_CTXTID)) &&
task_is_in_init_pid_ns(current))
task_is_in_init_pid_ns(event->owner)) /* bit[6], Context ID tracing bit */ config->cfg |= TRCCONFIGR_CID;@@ -710,7 +710,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, goto out; } /* Only trace virtual contextID when runs in root PID namespace */
Ditto.
/* Only trace virtual contextID when the tool runs in root PID namespace */
With above change:
Reviewed-by: Leo Yan leo.yan@arm.com
if (task_is_in_init_pid_ns(current))
if (task_is_in_init_pid_ns(event->owner)) config->cfg |= TRCCONFIGR_VMID | TRCCONFIGR_VMIDOPT; }-- 2.34.1
On 08/10/2024 07:52, Leo Yan wrote:
On 10/7/2024 9:05 PM, Leo Yan wrote:
Hi Julien,
On Wed, Sep 25, 2024 at 03:13:56PM +0200, Julien Meunier wrote:
The previous implementation limited the tracing capabilities when perf was run in the init PID namespace, making it impossible to trace applications in non-init PID namespaces.
This update improves the tracing process by verifying the event owner. This allows us to determine whether the user has the necessary permissions to trace the application.
The original commit aab473867fed is not for constraint permission. It is about PID namespace mismatching issue.
E.g. Perf runs in non-root namespace, thus it records process info in the non-root PID namespace. On the other hand, Arm CoreSight traces PID for root namespace, as a result, it will lead mess when decoding.
With this change, I am not convinced that Arm CoreSight can trace PID for non-root PID namespace. Seems to me, the concerned issue is still existed
- it might cause PID mismatching issue between hardware trace data and
Perf's process info.
I thought again and found I was wrong with above conclusion. This patch is a good fixing for the perf running in root namespace to profile programs in non-root namespace. Sorry for noise.
Maybe it is good to improve a bit comments to avoid confusion. See below.
[...]
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index bf01f01964cf..8365307b1aec 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -695,7 +695,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
/* Only trace contextID when runs in root PID namespace */We can claim the requirement for the *tool* running in root PID namespae.
/* Only trace contextID when the tool runs in root PID namespace */
minor nit: I wouldn't call "tool". Let keep it "event owner".
/* Only trace contextID when the event owner is in root PID namespace */
Julien,
Please could you respin the patch with the comments addressed.
Kind regards Suzuki
if ((attr->config & BIT(ETM_OPT_CTXTID)) &&
task_is_in_init_pid_ns(current))
task_is_in_init_pid_ns(event->owner)) /* bit[6], Context ID tracing bit */ config->cfg |= TRCCONFIGR_CID;@@ -710,7 +710,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, goto out; } /* Only trace virtual contextID when runs in root PID namespace */
Ditto.
/* Only trace virtual contextID when the tool runs in root PID namespace */
With above change:
Reviewed-by: Leo Yan leo.yan@arm.com
if (task_is_in_init_pid_ns(current))
if (task_is_in_init_pid_ns(event->owner)) config->cfg |= TRCCONFIGR_VMID | TRCCONFIGR_VMIDOPT; }-- 2.34.1
On 08/10/2024 11:59, Suzuki K Poulose wrote:
On 08/10/2024 07:52, Leo Yan wrote:
On 10/7/2024 9:05 PM, Leo Yan wrote:
[...]
I thought again and found I was wrong with above conclusion. This patch is a good fixing for the perf running in root namespace to profile programs in non-root namespace. Sorry for noise.
Maybe it is good to improve a bit comments to avoid confusion. See below.
[...]
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/ drivers/hwtracing/coresight/coresight-etm4x-core.c index bf01f01964cf..8365307b1aec 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -695,7 +695,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
/* Only trace contextID when runs in root PID namespace */
We can claim the requirement for the *tool* running in root PID namespae.
/* Only trace contextID when the tool runs in root PID namespace */
minor nit: I wouldn't call "tool". Let keep it "event owner".
/* Only trace contextID when the event owner is in root PID namespace */
Julien,
Please could you respin the patch with the comments addressed.
Sure, I will send a v2 with comments updated.
Kind regards Suzuki
if ((attr->config & BIT(ETM_OPT_CTXTID)) && - task_is_in_init_pid_ns(current)) + task_is_in_init_pid_ns(event->owner)) /* bit[6], Context ID tracing bit */ config->cfg |= TRCCONFIGR_CID;
@@ -710,7 +710,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, goto out; } /* Only trace virtual contextID when runs in root PID namespace */
Ditto.
/* Only trace virtual contextID when the tool runs in root PID namespace */
With above change:
Reviewed-by: Leo Yan leo.yan@arm.com
Regards, Julien
The previous implementation limited the tracing capabilities when perf was run in the init PID namespace, making it impossible to trace applications in non-init PID namespaces.
This update improves the tracing process by verifying the event owner. This allows us to determine whether the user has the necessary permissions to trace the application.
Cc: stable@vger.kernel.org Fixes: aab473867fed ("coresight: etm4x: Don't trace PID for non-root PID namespace") Signed-off-by: Julien Meunier julien.meunier@nokia.com --- Changes in v2: * Update comments --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 66d44a404ad0..cf41c42399e1 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -693,9 +693,9 @@ static int etm4_parse_event_config(struct coresight_device *csdev, config->cfg |= TRCCONFIGR_TS; }
- /* Only trace contextID when runs in root PID namespace */ + /* Only trace contextID when the event owner is in root PID namespace */ if ((attr->config & BIT(ETM_OPT_CTXTID)) && - task_is_in_init_pid_ns(current)) + task_is_in_init_pid_ns(event->owner)) /* bit[6], Context ID tracing bit */ config->cfg |= TRCCONFIGR_CID;
@@ -709,8 +709,8 @@ static int etm4_parse_event_config(struct coresight_device *csdev, ret = -EINVAL; goto out; } - /* Only trace virtual contextID when runs in root PID namespace */ - if (task_is_in_init_pid_ns(current)) + /* Only trace virtual contextID when the event owner is in root PID namespace */ + if (task_is_in_init_pid_ns(event->owner)) config->cfg |= TRCCONFIGR_VMID | TRCCONFIGR_VMIDOPT; }
On Tue, Oct 08, 2024 at 10:02:25PM +0200, Julien Meunier wrote:
The previous implementation limited the tracing capabilities when perf was run in the init PID namespace, making it impossible to trace applications in non-init PID namespaces.
This update improves the tracing process by verifying the event owner. This allows us to determine whether the user has the necessary permissions to trace the application.
Cc: stable@vger.kernel.org Fixes: aab473867fed ("coresight: etm4x: Don't trace PID for non-root PID namespace") Signed-off-by: Julien Meunier julien.meunier@nokia.com
Reviewed-by: Leo Yan leo.yan@linux.dev
Changes in v2:
- Update comments
drivers/hwtracing/coresight/coresight-etm4x-core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 66d44a404ad0..cf41c42399e1 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -693,9 +693,9 @@ static int etm4_parse_event_config(struct coresight_device *csdev, config->cfg |= TRCCONFIGR_TS; }
- /* Only trace contextID when runs in root PID namespace */
- /* Only trace contextID when the event owner is in root PID namespace */ if ((attr->config & BIT(ETM_OPT_CTXTID)) &&
task_is_in_init_pid_ns(current))
task_is_in_init_pid_ns(event->owner))@@ -709,8 +709,8 @@ static int etm4_parse_event_config(struct coresight_device *csdev, ret = -EINVAL; goto out; }
/* Only trace virtual contextID when runs in root PID namespace */if (task_is_in_init_pid_ns(current))
/* Only trace virtual contextID when the event owner is in root PID namespace */if (task_is_in_init_pid_ns(event->owner)) config->cfg |= TRCCONFIGR_VMID | TRCCONFIGR_VMIDOPT;2.34.1
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