This is a note to let you know that I've just added the patch titled
coresight: cti: Initialize dynamic sysfs attributes
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 80624263fa289b3416f7ca309491f1b75e579477 Mon Sep 17 00:00:00 2001
From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Date: Thu, 29 Oct 2020 10:45:58 -0600
Subject: coresight: cti: Initialize dynamic sysfs attributes
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@xxxxxxxxxx>
Tested-by: Leo Yan <leo.yan@xxxxxxxxxx>
Cc: Mike Leach <mike.leach@xxxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20201029164559.1268531-2-mathieu.poirier@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
}
--
2.29.1
