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Commit 291ad9a7 authored by Alessandro Rubini's avatar Alessandro Rubini
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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: 's avatarSasha Levin <sasha.levin@oracle.com>
Reported-by: 's avatarFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alessandro Rubini's avatarAlessandro Rubini <rubini@gnudd.com>
Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 766edad3
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Showing with 4 additions and 5 deletions
kernel/fmc-chardev.c
View file @ 291ad9a7
......@@ -142,18 +142,17 @@ 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;
......@@ -173,10 +172,10 @@ 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;
}
......
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