Messages in this thread Patch in this message | | | Subject | Re: [PATCH] soundwire: Fix DEBUG_LOCKS_WARN_ON for uninitialized attribute | From | Pierre-Louis Bossart <> | Date | Wed, 4 Nov 2020 08:32:19 -0600 |
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On 11/4/20 5:29 AM, Srinivas Kandagatla wrote: > running kernel with CONFIG_DEBUG_LOCKS_ALLOC enabled will below warning: > > BUG: key ffff502e09807098 has not been registered! > DEBUG_LOCKS_WARN_ON(1) > WARNING: CPU: 5 PID: 129 at kernel/locking/lockdep.c:4623 > lockdep_init_map_waits+0xe8/0x250 > Modules linked in: > CPU: 5 PID: 129 Comm: kworker/5:1 Tainted: G > W 5.10.0-rc1-00277-ged49f224ca3f-dirty #1210 > Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT) > Workqueue: events deferred_probe_work_func > pstate: 80c00005 (Nzcv daif +PAN +UAO -TCO BTYPE=--) > pc : lockdep_init_map_waits+0xe8/0x250 > lr : lockdep_init_map_waits+0xe8/0x250 > [ Trimmed ] > > Call trace: > lockdep_init_map_waits+0xe8/0x250 > __kernfs_create_file+0x78/0x180 > sysfs_add_file_mode_ns+0x94/0x1c8 > internal_create_group+0x110/0x3e0 > sysfs_create_group+0x18/0x28 > devm_device_add_group+0x4c/0xb0 > add_all_attributes+0x438/0x490 > sdw_slave_sysfs_dpn_init+0x128/0x138 > sdw_slave_sysfs_init+0x80/0xa0 > sdw_drv_probe+0x94/0x170 > really_probe+0x118/0x3e0 > driver_probe_device+0x5c/0xc0 > > [ Trimmed ] > > CPU: 5 PID: 129 Comm: kworker/5:1 Tainted: G > W 5.10.0-rc1-00277-ged49f224ca3f-dirty #1210 > Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT) > Workqueue: events deferred_probe_work_func > Call trace: > dump_backtrace+0x0/0x1c0 > show_stack+0x18/0x68 > dump_stack+0xd8/0x134 > __warn+0xa0/0x158 > report_bug+0xc8/0x178 > bug_handler+0x20/0x78 > brk_handler+0x70/0xc8 > > [ Trimmed ] > > Fix this by initializing dynamically allocated sysfs attribute to keep lockdep happy! > > Fixes: bcac59029955 ("soundwire: add Slave sysfs support") > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
I added the exact same fix last Friday but you beat me to it.
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
My commit message was a bit more self-explanatory though, maybe you could add the explanation at the end and possibly trim the logs?
" when CONFIG_DEBUG_LOCK_ALLOC is enabled, a warning is thrown, e.g.
kernel: [ 4.078863] BUG: key ffff8a9203c92dc0 has not been registered! kernel: [ 4.078865] ------------[ cut here ]------------ kernel: [ 4.078866] DEBUG_LOCKS_WARN_ON(1) kernel: [ 4.078871] WARNING: CPU: 0 PID: 280 at kernel/locking/lockdep.c:4623 lockdep_init_map_waits+0x177/0x200 kernel: [ 4.078902] Call Trace: kernel: [ 4.078906] __kernfs_create_file+0x76/0x100 kernel: [ 4.078908] sysfs_add_file_mode_ns+0x9f/0x190 kernel: [ 4.078909] internal_create_group+0x112/0x380 kernel: [ 4.078912] devm_device_add_group+0x41/0x80 kernel: [ 4.078915] add_all_attributes+0x4bf/0x4e0 [soundwire_bus] kernel: [ 4.078918] sdw_slave_sysfs_dpn_init+0x68/0xe0 [soundwire_bus] kernel: [ 4.078920] sdw_slave_sysfs_init+0x6b/0x80 [soundwire_bus]
For DPn ports, the attributes are allocated dynamically and it's required to use the macro sysfs_attr_init(), whose behavior is precisely dependent on CONFIG_DEBUG_LOCK_ALLOC. See details in linux/sysfs.h. "
Thanks Srinivas!
> --- > drivers/soundwire/sysfs_slave_dpn.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/soundwire/sysfs_slave_dpn.c b/drivers/soundwire/sysfs_slave_dpn.c > index 05a721ea9830..c4b6543c09fd 100644 > --- a/drivers/soundwire/sysfs_slave_dpn.c > +++ b/drivers/soundwire/sysfs_slave_dpn.c > @@ -37,6 +37,7 @@ static int field##_attribute_alloc(struct device *dev, \ > return -ENOMEM; \ > dpn_attr->N = N; \ > dpn_attr->dir = dir; \ > + sysfs_attr_init(&dpn_attr->dev_attr.attr); \ > dpn_attr->format_string = format_string; \ > dpn_attr->dev_attr.attr.name = __stringify(field); \ > dpn_attr->dev_attr.attr.mode = 0444; \ >
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