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authorAdrian Hunter <adrian.hunter@intel.com>2017-11-21 15:42:30 +0200
committerUlf Hansson <ulf.hansson@linaro.org>2017-11-23 14:39:13 +0100
commitf9f0da98819503b06b35e61869d18cf3a8cd3323 (patch)
tree3958ac5701d4c83a9b79f27bbdb40df395aaa7db /drivers/mmc/core
parentebe7dd45cf49e3b49cacbaace17f9f878f21fbea (diff)
mmc: block: Ensure that debugfs files are removed
The card is not necessarily being removed, but the debugfs files must be removed when the driver is removed, otherwise they will continue to exist after unbinding the card from the driver. e.g. # echo "mmc1:0001" > /sys/bus/mmc/drivers/mmcblk/unbind # cat /sys/kernel/debug/mmc1/mmc1\:0001/ext_csd [ 173.634584] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050 [ 173.643356] IP: mmc_ext_csd_open+0x5e/0x170 A complication is that the debugfs_root may have already been removed, so check for that too. Fixes: 627c3ccfb46a ("mmc: debugfs: Move block debugfs into block module") Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Cc: stable@vger.kernel.org # 4.14+ Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc/core')
-rw-r--r--drivers/mmc/core/block.c44
-rw-r--r--drivers/mmc/core/debugfs.c1
2 files changed, 38 insertions, 7 deletions
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 4a319ddbd956..ccfa98af1dd3 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -122,6 +122,10 @@ struct mmc_blk_data {
struct device_attribute force_ro;
struct device_attribute power_ro_lock;
int area_type;
+
+ /* debugfs files (only in main mmc_blk_data) */
+ struct dentry *status_dentry;
+ struct dentry *ext_csd_dentry;
};
/* Device type for RPMB character devices */
@@ -2653,7 +2657,7 @@ static const struct file_operations mmc_dbg_ext_csd_fops = {
.llseek = default_llseek,
};
-static int mmc_blk_add_debugfs(struct mmc_card *card)
+static int mmc_blk_add_debugfs(struct mmc_card *card, struct mmc_blk_data *md)
{
struct dentry *root;
@@ -2663,28 +2667,53 @@ static int mmc_blk_add_debugfs(struct mmc_card *card)
root = card->debugfs_root;
if (mmc_card_mmc(card) || mmc_card_sd(card)) {
- if (!debugfs_create_file("status", S_IRUSR, root, card,
- &mmc_dbg_card_status_fops))
+ md->status_dentry =
+ debugfs_create_file("status", S_IRUSR, root, card,
+ &mmc_dbg_card_status_fops);
+ if (!md->status_dentry)
return -EIO;
}
if (mmc_card_mmc(card)) {
- if (!debugfs_create_file("ext_csd", S_IRUSR, root, card,
- &mmc_dbg_ext_csd_fops))
+ md->ext_csd_dentry =
+ debugfs_create_file("ext_csd", S_IRUSR, root, card,
+ &mmc_dbg_ext_csd_fops);
+ if (!md->ext_csd_dentry)
return -EIO;
}
return 0;
}
+static void mmc_blk_remove_debugfs(struct mmc_card *card,
+ struct mmc_blk_data *md)
+{
+ if (!card->debugfs_root)
+ return;
+
+ if (!IS_ERR_OR_NULL(md->status_dentry)) {
+ debugfs_remove(md->status_dentry);
+ md->status_dentry = NULL;
+ }
+
+ if (!IS_ERR_OR_NULL(md->ext_csd_dentry)) {
+ debugfs_remove(md->ext_csd_dentry);
+ md->ext_csd_dentry = NULL;
+ }
+}
#else
-static int mmc_blk_add_debugfs(struct mmc_card *card)
+static int mmc_blk_add_debugfs(struct mmc_card *card, struct mmc_blk_data *md)
{
return 0;
}
+static void mmc_blk_remove_debugfs(struct mmc_card *card,
+ struct mmc_blk_data *md)
+{
+}
+
#endif /* CONFIG_DEBUG_FS */
static int mmc_blk_probe(struct mmc_card *card)
@@ -2724,7 +2753,7 @@ static int mmc_blk_probe(struct mmc_card *card)
}
/* Add two debugfs entries */
- mmc_blk_add_debugfs(card);
+ mmc_blk_add_debugfs(card, md);
pm_runtime_set_autosuspend_delay(&card->dev, 3000);
pm_runtime_use_autosuspend(&card->dev);
@@ -2750,6 +2779,7 @@ static void mmc_blk_remove(struct mmc_card *card)
{
struct mmc_blk_data *md = dev_get_drvdata(&card->dev);
+ mmc_blk_remove_debugfs(card, md);
mmc_blk_remove_parts(card, md);
pm_runtime_get_sync(&card->dev);
mmc_claim_host(card->host);
diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index 01e459a34f33..0f4a7d7b2626 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -314,4 +314,5 @@ err:
void mmc_remove_card_debugfs(struct mmc_card *card)
{
debugfs_remove_recursive(card->debugfs_root);
+ card->debugfs_root = NULL;
}

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