[PATCH 0/2] coresight: Fixes for v5.10-rc2

[PATCH 0/2] coresight: Fixes for v5.10-rc2

[Mathieu Poirier]

Hi Greg,

Please consider those when collecting fixes for this cycle.

Thanks,
Mathieu

Mike Leach (1):
  coresight: Fix uninitialised pointer bug in etm_setup_aux()

Suzuki K Poulose (1):
  coresight: cti: Initialize dynamic sysfs attributes

 drivers/hwtracing/coresight/coresight-cti-sysfs.c | 7 +++++++
 drivers/hwtracing/coresight/coresight-etm-perf.c  | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

-- 
2.25.1

[PATCH 1/2] coresight: cti: Initialize dynamic sysfs attributes

[Mathieu Poirier]

From: Suzuki K Poulose <suzuki.poulose@arm.com>

With LOCKDEP enabled, CTI driver triggers the following splat due
to uninitialized lock class for dynamically allocated attribute
objects.

[    5.372901] coresight etm0: CPU0: ETM v4.0 initialized
[    5.376694] coresight etm1: CPU1: ETM v4.0 initialized
[    5.380785] coresight etm2: CPU2: ETM v4.0 initialized
[    5.385851] coresight etm3: CPU3: ETM v4.0 initialized
[    5.389808] BUG: key ffff00000564a798 has not been registered!
[    5.392456] ------------[ cut here ]------------
[    5.398195] DEBUG_LOCKS_WARN_ON(1)
[    5.398233] WARNING: CPU: 1 PID: 32 at kernel/locking/lockdep.c:4623 lockdep_init_map_waits+0x14c/0x260
[    5.406149] Modules linked in:
[    5.415411] CPU: 1 PID: 32 Comm: kworker/1:1 Not tainted 5.9.0-12034-gbbe85027ce80 #51
[    5.418553] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
[    5.426453] Workqueue: events amba_deferred_retry_func
[    5.433299] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
[    5.438252] pc : lockdep_init_map_waits+0x14c/0x260
[    5.444410] lr : lockdep_init_map_waits+0x14c/0x260
[    5.449007] sp : ffff800012bbb720
...

[    5.531561] Call trace:
[    5.536847]  lockdep_init_map_waits+0x14c/0x260
[    5.539027]  __kernfs_create_file+0xa8/0x1c8
[    5.543539]  sysfs_add_file_mode_ns+0xd0/0x208
[    5.548054]  internal_create_group+0x118/0x3c8
[    5.552307]  internal_create_groups+0x58/0xb8
[    5.556733]  sysfs_create_groups+0x2c/0x38
[    5.561160]  device_add+0x2d8/0x768
[    5.565148]  device_register+0x28/0x38
[    5.568537]  coresight_register+0xf8/0x320
[    5.572358]  cti_probe+0x1b0/0x3f0

...

Fix this by initializing the attributes when they are allocated.

Fixes: 3c5597e39812 ("coresight: cti: Add connection information to sysfs")
Reported-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/hwtracing/coresight/coresight-cti-sysfs.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
index 392757f3a019..7ff7e7780bbf 100644
--- a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
@@ -1065,6 +1065,13 @@ static int cti_create_con_sysfs_attr(struct device *dev,
 	}
 	eattr->var = con;
 	con->con_attrs[attr_idx] = &eattr->attr.attr;
+	/*
+	 * Initialize the dynamically allocated attribute
+	 * to avoid LOCKDEP splat. See include/linux/sysfs.h
+	 * for more details.
+	 */
+	sysfs_attr_init(con->con_attrs[attr_idx]);
+
 	return 0;
 }
 
-- 
2.25.1

[PATCH 2/2] coresight: Fix uninitialised pointer bug in etm_setup_aux()

[Mathieu Poirier]

From: Mike Leach <mike.leach@linaro.org>

Commit [bb1860efc817] changed the sink handling code introducing an
uninitialised pointer bug. This results in the default sink selection
failing.

Prior to commit:

static void etm_setup_aux(...)

<snip>
        struct coresight_device *sink;
<snip>

        /* First get the selected sink from user space. */
        if (event->attr.config2) {
                id = (u32)event->attr.config2;
                sink = coresight_get_sink_by_id(id);
        } else {
                sink = coresight_get_enabled_sink(true);
        }
<ctd>

*sink always initialised - possibly to NULL which triggers the
automatic sink selection.

After commit:

static void etm_setup_aux(...)

<snip>
        struct coresight_device *sink;
<snip>

        /* First get the selected sink from user space. */
        if (event->attr.config2) {
                id = (u32)event->attr.config2;
                sink = coresight_get_sink_by_id(id);
        }
<ctd>

*sink pointer uninitialised when not providing a sink on the perf command
line. This breaks later checks to enable automatic sink selection.

Fixes: bb1860efc817 ("coresight: etm: perf: Sink selection using sysfs is deprecated")
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/hwtracing/coresight/coresight-etm-perf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index c2c9b127d074..bdc34ca449f7 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -210,7 +210,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 	u32 id;
 	int cpu = event->cpu;
 	cpumask_t *mask;
-	struct coresight_device *sink;
+	struct coresight_device *sink = NULL;
 	struct etm_event_data *event_data = NULL;
 
 	event_data = alloc_event_data(cpu);
-- 
2.25.1

Re: [PATCH 1/2] coresight: cti: Initialize dynamic sysfs attributes

[Greg KH]

On Thu, Oct 29, 2020 at 10:45:58AM -0600, Mathieu Poirier wrote:
> From: Suzuki K Poulose <suzuki.poulose@arm.com>
> 
> With LOCKDEP enabled, CTI driver triggers the following splat due
> to uninitialized lock class for dynamically allocated attribute
> objects.
> 
> [    5.372901] coresight etm0: CPU0: ETM v4.0 initialized
> [    5.376694] coresight etm1: CPU1: ETM v4.0 initialized
> [    5.380785] coresight etm2: CPU2: ETM v4.0 initialized
> [    5.385851] coresight etm3: CPU3: ETM v4.0 initialized
> [    5.389808] BUG: key ffff00000564a798 has not been registered!
> [    5.392456] ------------[ cut here ]------------
> [    5.398195] DEBUG_LOCKS_WARN_ON(1)
> [    5.398233] WARNING: CPU: 1 PID: 32 at kernel/locking/lockdep.c:4623 lockdep_init_map_waits+0x14c/0x260
> [    5.406149] Modules linked in:
> [    5.415411] CPU: 1 PID: 32 Comm: kworker/1:1 Not tainted 5.9.0-12034-gbbe85027ce80 #51
> [    5.418553] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
> [    5.426453] Workqueue: events amba_deferred_retry_func
> [    5.433299] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
> [    5.438252] pc : lockdep_init_map_waits+0x14c/0x260
> [    5.444410] lr : lockdep_init_map_waits+0x14c/0x260
> [    5.449007] sp : ffff800012bbb720
> ...
> 
> [    5.531561] Call trace:
> [    5.536847]  lockdep_init_map_waits+0x14c/0x260
> [    5.539027]  __kernfs_create_file+0xa8/0x1c8
> [    5.543539]  sysfs_add_file_mode_ns+0xd0/0x208
> [    5.548054]  internal_create_group+0x118/0x3c8
> [    5.552307]  internal_create_groups+0x58/0xb8
> [    5.556733]  sysfs_create_groups+0x2c/0x38
> [    5.561160]  device_add+0x2d8/0x768
> [    5.565148]  device_register+0x28/0x38
> [    5.568537]  coresight_register+0xf8/0x320
> [    5.572358]  cti_probe+0x1b0/0x3f0
> 
> ...
> 
> Fix this by initializing the attributes when they are allocated.
> 
> Fixes: 3c5597e39812 ("coresight: cti: Add connection information to sysfs")
> Reported-by: Leo Yan <leo.yan@linaro.org>
> Tested-by: Leo Yan <leo.yan@linaro.org>
> Cc: Mike Leach <mike.leach@linaro.org>
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> ---
>  drivers/hwtracing/coresight/coresight-cti-sysfs.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> index 392757f3a019..7ff7e7780bbf 100644
> --- a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> @@ -1065,6 +1065,13 @@ static int cti_create_con_sysfs_attr(struct device *dev,
>  	}
>  	eattr->var = con;
>  	con->con_attrs[attr_idx] = &eattr->attr.attr;
> +	/*
> +	 * Initialize the dynamically allocated attribute
> +	 * to avoid LOCKDEP splat. See include/linux/sysfs.h
> +	 * for more details.
> +	 */
> +	sysfs_attr_init(con->con_attrs[attr_idx]);
> +
>  	return 0;
>  }

Should go to stable kernels too, as the patch this fixes is in 5.7.
I'll add the stable tag here, but feel free to do it yourself next time
:)

thanks,

greg k-h

Re: [PATCH 1/2] coresight: cti: Initialize dynamic sysfs attributes

[Mathieu Poirier]

On Thu, Oct 29, 2020 at 08:10:11PM +0100, Greg KH wrote:
> On Thu, Oct 29, 2020 at 10:45:58AM -0600, Mathieu Poirier wrote:
> > From: Suzuki K Poulose <suzuki.poulose@arm.com>
> > 
> > With LOCKDEP enabled, CTI driver triggers the following splat due
> > to uninitialized lock class for dynamically allocated attribute
> > objects.
> > 
> > [    5.372901] coresight etm0: CPU0: ETM v4.0 initialized
> > [    5.376694] coresight etm1: CPU1: ETM v4.0 initialized
> > [    5.380785] coresight etm2: CPU2: ETM v4.0 initialized
> > [    5.385851] coresight etm3: CPU3: ETM v4.0 initialized
> > [    5.389808] BUG: key ffff00000564a798 has not been registered!
> > [    5.392456] ------------[ cut here ]------------
> > [    5.398195] DEBUG_LOCKS_WARN_ON(1)
> > [    5.398233] WARNING: CPU: 1 PID: 32 at kernel/locking/lockdep.c:4623 lockdep_init_map_waits+0x14c/0x260
> > [    5.406149] Modules linked in:
> > [    5.415411] CPU: 1 PID: 32 Comm: kworker/1:1 Not tainted 5.9.0-12034-gbbe85027ce80 #51
> > [    5.418553] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
> > [    5.426453] Workqueue: events amba_deferred_retry_func
> > [    5.433299] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
> > [    5.438252] pc : lockdep_init_map_waits+0x14c/0x260
> > [    5.444410] lr : lockdep_init_map_waits+0x14c/0x260
> > [    5.449007] sp : ffff800012bbb720
> > ...
> > 
> > [    5.531561] Call trace:
> > [    5.536847]  lockdep_init_map_waits+0x14c/0x260
> > [    5.539027]  __kernfs_create_file+0xa8/0x1c8
> > [    5.543539]  sysfs_add_file_mode_ns+0xd0/0x208
> > [    5.548054]  internal_create_group+0x118/0x3c8
> > [    5.552307]  internal_create_groups+0x58/0xb8
> > [    5.556733]  sysfs_create_groups+0x2c/0x38
> > [    5.561160]  device_add+0x2d8/0x768
> > [    5.565148]  device_register+0x28/0x38
> > [    5.568537]  coresight_register+0xf8/0x320
> > [    5.572358]  cti_probe+0x1b0/0x3f0
> > 
> > ...
> > 
> > Fix this by initializing the attributes when they are allocated.
> > 
> > Fixes: 3c5597e39812 ("coresight: cti: Add connection information to sysfs")
> > Reported-by: Leo Yan <leo.yan@linaro.org>
> > Tested-by: Leo Yan <leo.yan@linaro.org>
> > Cc: Mike Leach <mike.leach@linaro.org>
> > Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> > Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> > ---
> >  drivers/hwtracing/coresight/coresight-cti-sysfs.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > index 392757f3a019..7ff7e7780bbf 100644
> > --- a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > +++ b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > @@ -1065,6 +1065,13 @@ static int cti_create_con_sysfs_attr(struct device *dev,
> >  	}
> >  	eattr->var = con;
> >  	con->con_attrs[attr_idx] = &eattr->attr.attr;
> > +	/*
> > +	 * Initialize the dynamically allocated attribute
> > +	 * to avoid LOCKDEP splat. See include/linux/sysfs.h
> > +	 * for more details.
> > +	 */
> > +	sysfs_attr_init(con->con_attrs[attr_idx]);
> > +
> >  	return 0;
> >  }
> 
> Should go to stable kernels too, as the patch this fixes is in 5.7.
> I'll add the stable tag here, but feel free to do it yourself next time
> :)

Oh - I (wrongly) assumed all patches with a "Fixes" tag were going to stable. 

> 
> thanks,
> 
> greg k-h