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authorLinus Walleij <linus.walleij@linaro.org>2017-10-04 11:10:07 +0200
committerUlf Hansson <ulf.hansson@linaro.org>2017-10-30 11:44:49 +0100
commit1c87f73578497a6c3cc77bcbfd2e5bf15fe753c7 (patch)
tree799c9294c9474bc8af92a9fa734be06f228488d8 /drivers/mmc/core
parent14f4ca7e4d2825f9f71e22905ae177b899959f1d (diff)
downloadlinux-1c87f73578497a6c3cc77bcbfd2e5bf15fe753c7.tar.bz2
mmc: block: Fix bug when removing RPMB chardev
I forgot to account for the fact that the device core holds a reference to a device added with device_initialize() that need to be released with a corresponding put_device() to reach a 0 refcount at the end of the lifecycle. This led to a NULL pointer reference when freeing the device when e.g. unbidning the host device in sysfs. Fix this and use the device .release() callback to free the IDA and free:ing the memory used by the RPMB device. Before this patch: /sys/bus/amba/drivers/mmci-pl18x$ echo 80114000.sdi4_per2 > unbind [ 29.797332] mmc3: card 0001 removed [ 29.810791] Unable to handle kernel NULL pointer dereference at virtual address 00000050 [ 29.818878] pgd = de70c000 [ 29.821624] [00000050] *pgd=1e70a831, *pte=00000000, *ppte=00000000 [ 29.827911] Internal error: Oops: 17 [#1] PREEMPT SMP ARM [ 29.833282] Modules linked in: [ 29.836334] CPU: 1 PID: 154 Comm: sh Not tainted 4.14.0-rc3-00039-g83318e309566-dirty #736 [ 29.844604] Hardware name: ST-Ericsson Ux5x0 platform (Device Tree Support) [ 29.851562] task: de572700 task.stack: de742000 [ 29.856079] PC is at kernfs_find_ns+0x8/0x100 [ 29.860443] LR is at kernfs_find_and_get_ns+0x30/0x48 After this patch: /sys/bus/amba/drivers/mmci-pl18x$ echo 80005000.sdi4_per2 > unbind [ 20.623382] mmc3: card 0001 removed Fixes: 97548575bef3 ("mmc: block: Convert RPMB to a character device") Reported-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc/core')
-rw-r--r--drivers/mmc/core/block.c32
1 files changed, 18 insertions, 14 deletions
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index ab9c780df750..f11537a66a60 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2277,9 +2277,7 @@ static int mmc_rpmb_chrdev_open(struct inode *inode, struct file *filp)
get_device(&rpmb->dev);
filp->private_data = rpmb;
- mutex_lock(&open_lock);
- rpmb->md->usage++;
- mutex_unlock(&open_lock);
+ mmc_blk_get(rpmb->md->disk);
return nonseekable_open(inode, filp);
}
@@ -2290,9 +2288,7 @@ static int mmc_rpmb_chrdev_release(struct inode *inode, struct file *filp)
struct mmc_rpmb_data, chrdev);
put_device(&rpmb->dev);
- mutex_lock(&open_lock);
- rpmb->md->usage--;
- mutex_unlock(&open_lock);
+ mmc_blk_put(rpmb->md);
return 0;
}
@@ -2308,6 +2304,13 @@ static const struct file_operations mmc_rpmb_fileops = {
#endif
};
+static void mmc_blk_rpmb_device_release(struct device *dev)
+{
+ struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
+
+ ida_simple_remove(&mmc_rpmb_ida, rpmb->id);
+ kfree(rpmb);
+}
static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
struct mmc_blk_data *md,
@@ -2326,8 +2329,10 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
return devidx;
rpmb = kzalloc(sizeof(*rpmb), GFP_KERNEL);
- if (!rpmb)
+ if (!rpmb) {
+ ida_simple_remove(&mmc_rpmb_ida, devidx);
return -ENOMEM;
+ }
snprintf(rpmb_name, sizeof(rpmb_name),
"mmcblk%u%s", card->host->index, subname ? subname : "");
@@ -2338,6 +2343,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
rpmb->dev.bus = &mmc_rpmb_bus_type;
rpmb->dev.devt = MKDEV(MAJOR(mmc_rpmb_devt), rpmb->id);
rpmb->dev.parent = &card->dev;
+ rpmb->dev.release = mmc_blk_rpmb_device_release;
device_initialize(&rpmb->dev);
dev_set_drvdata(&rpmb->dev, rpmb);
rpmb->md = md;
@@ -2347,7 +2353,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
ret = cdev_device_add(&rpmb->chrdev, &rpmb->dev);
if (ret) {
pr_err("%s: could not add character device\n", rpmb_name);
- goto out_remove_ida;
+ goto out_put_device;
}
list_add(&rpmb->node, &md->rpmbs);
@@ -2362,18 +2368,16 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
return 0;
-out_remove_ida:
- ida_simple_remove(&mmc_rpmb_ida, rpmb->id);
- kfree(rpmb);
+out_put_device:
+ put_device(&rpmb->dev);
return ret;
}
static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb)
+
{
cdev_device_del(&rpmb->chrdev, &rpmb->dev);
- device_del(&rpmb->dev);
- ida_simple_remove(&mmc_rpmb_ida, rpmb->id);
- kfree(rpmb);
+ put_device(&rpmb->dev);
}
/* MMC Physical partitions consist of two boot partitions and