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authorAlessandro Rubini <rubini@gnudd.com>2013-07-16 12:58:01 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-24 22:56:52 -0700
commit783c2fb1b8ba2f057a26f881aa452d4aa8e4b3f4 (patch)
tree13f18c989ccb4e748b8db58532faf24450b5c958 /drivers/fmc
parent5f90b9b484938f7466e25cd5506e86ebf9dbcd17 (diff)
downloadkernel-783c2fb1b8ba2f057a26f881aa452d4aa8e4b3f4.tar.gz
FMC: fix locking in sample chardev driver
The fmc-chardev module was over-locking, by calling misc register/unregister while holding its spinlock. This reported a "scheduling while atomic" error. Since the misc driver already serializes operations internally, this commit downgrades the fmc-chardev lock to just cover its own list. Reported-by: Sasha Levin <sasha.levin@oracle.com> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Alessandro Rubini <rubini@gnudd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/fmc')
-rw-r--r--drivers/fmc/fmc-chardev.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/fmc/fmc-chardev.c b/drivers/fmc/fmc-chardev.c
index cc031db2d2a3..ace6ef24d15e 100644
--- a/drivers/fmc/fmc-chardev.c
+++ b/drivers/fmc/fmc-chardev.c
@@ -143,18 +143,17 @@ static int fc_probe(struct fmc_device *fmc)
fc->misc.fops = &fc_fops;
fc->misc.name = kstrdup(dev_name(&fmc->dev), GFP_KERNEL);
- spin_lock(&fc_lock);
ret = misc_register(&fc->misc);
if (ret < 0)
- goto err_unlock;
+ goto out;
+ spin_lock(&fc_lock);
list_add(&fc->list, &fc_devices);
spin_unlock(&fc_lock);
dev_info(&fc->fmc->dev, "Created misc device \"%s\"\n",
fc->misc.name);
return 0;
-err_unlock:
- spin_unlock(&fc_lock);
+out:
kfree(fc->misc.name);
kfree(fc);
return ret;
@@ -174,10 +173,10 @@ static int fc_remove(struct fmc_device *fmc)
spin_lock(&fc_lock);
list_del(&fc->list);
+ spin_unlock(&fc_lock);
misc_deregister(&fc->misc);
kfree(fc->misc.name);
kfree(fc);
- spin_unlock(&fc_lock);
return 0;
}