From: Suzuki K Poulose suzuki.poulose@arm.com
commit 80624263fa289b3416f7ca309491f1b75e579477 upstream.
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 Cc: stable stable@vger.kernel.org Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org Link: https://lore.kernel.org/r/20201029164559.1268531-2-mathieu.poirier@linaro.or... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/hwtracing/coresight/coresight-cti-sysfs.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- 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(str } 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; }