| Message ID | 20230404155121.1824126-2-james.clark@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | coresight: Fix CTI module refcount leak by making it a helper device | expand |
On Tue, 4 Apr 2023 at 16:51, James Clark <james.clark@arm.com> wrote: > > child_fwnode should be a read only property based on the DT or ACPI. If > it's cleared on the parent device when a child is unloaded, then when > the child is loaded again the connection won't be remade. > > child_dev should be cleared instead which signifies that the connection > should be remade when the child_fwnode registers a new coresight_device. > > Similarly the reference count shouldn't be decremented as long as the > parent device exists. The correct place to drop the reference is in > coresight_release_platform_data() which is already done. > > Reproducible on Juno with the following steps: > > # load all coresight modules. > $ cd /sys/bus/coresight/devices/ > $ echo 1 > tmc_etr0/enable_sink > $ echo 1 > etm0/enable_source > # Works fine ^ > > $ echo 0 > etm0/enable_source > $ rmmod coresight-funnel > $ modprobe coresight-funnel > $ echo 1 > etm0/enable_source > -bash: echo: write error: Invalid argument > > Fixes: 37ea1ffddffa ("coresight: Use fwnode handle instead of device names") > Fixes: 2af89ebacf29 ("coresight: Clear the connection field properly") > Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com> > Signed-off-by: James Clark <james.clark@arm.com> > --- > drivers/hwtracing/coresight/coresight-core.c | 9 ++------- > 1 file changed, 2 insertions(+), 7 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c > index d3bf82c0de1d..5733294ce5cd 100644 > --- a/drivers/hwtracing/coresight/coresight-core.c > +++ b/drivers/hwtracing/coresight/coresight-core.c > @@ -1419,13 +1419,8 @@ static int coresight_remove_match(struct device *dev, void *data) > if (csdev->dev.fwnode == conn->child_fwnode) { > iterator->orphan = true; > coresight_remove_links(iterator, conn); > - /* > - * Drop the reference to the handle for the remote > - * device acquired in parsing the connections from > - * platform data. > - */ > - fwnode_handle_put(conn->child_fwnode); > - conn->child_fwnode = NULL; > + > + conn->child_dev = NULL; > /* No need to continue */ > break; > } > -- > 2.34.1 > Reviewed-by: Mike Leach <mike.leach@linaro.org>
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index d3bf82c0de1d..5733294ce5cd 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -1419,13 +1419,8 @@ static int coresight_remove_match(struct device *dev, void *data) if (csdev->dev.fwnode == conn->child_fwnode) { iterator->orphan = true; coresight_remove_links(iterator, conn); - /* - * Drop the reference to the handle for the remote - * device acquired in parsing the connections from - * platform data. - */ - fwnode_handle_put(conn->child_fwnode); - conn->child_fwnode = NULL; + + conn->child_dev = NULL; /* No need to continue */ break; }
child_fwnode should be a read only property based on the DT or ACPI. If it's cleared on the parent device when a child is unloaded, then when the child is loaded again the connection won't be remade. child_dev should be cleared instead which signifies that the connection should be remade when the child_fwnode registers a new coresight_device. Similarly the reference count shouldn't be decremented as long as the parent device exists. The correct place to drop the reference is in coresight_release_platform_data() which is already done. Reproducible on Juno with the following steps: # load all coresight modules. $ cd /sys/bus/coresight/devices/ $ echo 1 > tmc_etr0/enable_sink $ echo 1 > etm0/enable_source # Works fine ^ $ echo 0 > etm0/enable_source $ rmmod coresight-funnel $ modprobe coresight-funnel $ echo 1 > etm0/enable_source -bash: echo: write error: Invalid argument Fixes: 37ea1ffddffa ("coresight: Use fwnode handle instead of device names") Fixes: 2af89ebacf29 ("coresight: Clear the connection field properly") Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: James Clark <james.clark@arm.com> --- drivers/hwtracing/coresight/coresight-core.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)