From 783c2fb1b8ba2f057a26f881aa452d4aa8e4b3f4 Mon Sep 17 00:00:00 2001 From: Alessandro Rubini Date: Tue, 16 Jul 2013 12:58:01 +0200 Subject: [PATCH] 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 Reported-by: Fengguang Wu Signed-off-by: Alessandro Rubini Signed-off-by: Greg Kroah-Hartman --- drivers/fmc/fmc-chardev.c | 9 ++++----- 1 file 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; }