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coresight: cti: Initialize dynamic sysfs attributes
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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: 3c5597e ("coresight: cti: Add connection information to sysfs")
Reported-by: Leo Yan <[email protected]>
Tested-by: Leo Yan <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Mathieu Poirier <[email protected]>
Signed-off-by: Suzuki K Poulose <[email protected]>
Cc: stable <[email protected]>
Signed-off-by: Mathieu Poirier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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Suzuki K Poulose authored and gregkh committed Oct 29, 2020
1 parent 39a7661 commit 8062426
Showing 1 changed file with 7 additions and 0 deletions.
7 changes: 7 additions & 0 deletions drivers/hwtracing/coresight/coresight-cti-sysfs.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
}

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