From: Ulf Hansson <ulf.hansson@linaro.org>
To: linux-mmc@vger.kernel.org, Ulf Hansson <ulf.hansson@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>, linux-kernel@vger.kernel.org
Subject: [PATCH 3/3] mmc: block: Fix error path in mmc_blk_probe()
Date: Wed, 3 Mar 2021 13:20:49 +0100 [thread overview]
Message-ID: <20210303122049.151986-4-ulf.hansson@linaro.org> (raw)
In-Reply-To: <20210303122049.151986-1-ulf.hansson@linaro.org>
Returning zero to indicate success, when we actually have failed to probe
is wrong. As a matter of fact, it leads to that mmc_blk_remove() gets
called at a card removal and then triggers "NULL pointer dereference"
splats. This is because mmc_blk_remove() relies on data structures and
pointers to be setup from mmc_blk_probe(), of course.
There have been no errors reported about this, which is most likely because
mmc_blk_probe() never fails like this. Nevertheless, let's fix the code by
propagating the error codes correctly and prevent us from leaking memory by
calling also destroy_workqueue() in the error path.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
drivers/mmc/core/block.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 39308b35a1fb..02b656305042 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2876,6 +2876,7 @@ static void mmc_blk_remove_debugfs(struct mmc_card *card,
static int mmc_blk_probe(struct mmc_card *card)
{
struct mmc_blk_data *md, *part_md;
+ int ret = 0;
/*
* Check that the card supports the command class(es) we need.
@@ -2893,19 +2894,24 @@ static int mmc_blk_probe(struct mmc_card *card)
}
md = mmc_blk_alloc(card);
- if (IS_ERR(md))
- return PTR_ERR(md);
+ if (IS_ERR(md)) {
+ ret = PTR_ERR(md);
+ goto out_free;
+ }
- if (mmc_blk_alloc_parts(card, md))
+ ret = mmc_blk_alloc_parts(card, md);
+ if (ret)
goto out;
dev_set_drvdata(&card->dev, md);
- if (mmc_add_disk(md))
+ ret = mmc_add_disk(md);
+ if (ret)
goto out;
list_for_each_entry(part_md, &md->part, part) {
- if (mmc_add_disk(part_md))
+ ret = mmc_add_disk(part_md);
+ if (ret)
goto out;
}
@@ -2926,10 +2932,12 @@ static int mmc_blk_probe(struct mmc_card *card)
return 0;
- out:
+out:
mmc_blk_remove_parts(card, md);
mmc_blk_remove_req(md);
- return 0;
+out_free:
+ destroy_workqueue(card->complete_wq);
+ return ret;
}
static void mmc_blk_remove(struct mmc_card *card)
--
2.25.1
prev parent reply other threads:[~2021-03-03 17:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-03 12:20 [PATCH 0/3] mmc: block: Cleanup mmc_blk_probe() path Ulf Hansson
2021-03-03 12:20 ` [PATCH 1/3] mmc: block: Drop use of unlikely() in mmc_blk_probe() Ulf Hansson
2021-03-03 12:20 ` [PATCH 2/3] mmc: block: Simplify logging during probe about added partitions Ulf Hansson
2021-03-03 12:20 ` Ulf Hansson [this message]
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