[PATCH v2] mtd: Add check and kfree() for kcalloc()

[Jiasheng Jiang]

Add a check for kcalloc() to ensure successful allocation.
Moreover, add kfree() in the error-handling path to prevent memory leaks.

Fixes: 78c08247b9d3 ("mtd: Support kmsg dumper based on pstore/blk")
Cc: <stable at vger.kernel.org> # v5.10+
Signed-off-by: Jiasheng Jiang <jiashengjiangcool at gmail.com>
---
Changelog:

v1 -> v2:

1. Remove redundant logging.
2. Add kfree() in the error-handling path.
---
 drivers/mtd/mtdpstore.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/mtdpstore.c b/drivers/mtd/mtdpstore.c
index 7ac8ac901306..2d8e330dd215 100644
--- a/drivers/mtd/mtdpstore.c
+++ b/drivers/mtd/mtdpstore.c
@@ -418,10 +418,17 @@ static void mtdpstore_notify_add(struct mtd_info *mtd)
 
 	longcnt = BITS_TO_LONGS(div_u64(mtd->size, info->kmsg_size));
 	cxt->rmmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL);
+	if (!cxt->rmmap)
+		goto end;
+
 	cxt->usedmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL);
+	if (!cxt->usedmap)
+		goto free_rmmap;
 
 	longcnt = BITS_TO_LONGS(div_u64(mtd->size, mtd->erasesize));
 	cxt->badmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL);
+	if (!cxt->badmap)
+		goto free_usedmap;
 
 	/* just support dmesg right now */
 	cxt->dev.flags = PSTORE_FLAGS_DMESG;
@@ -435,10 +442,20 @@ static void mtdpstore_notify_add(struct mtd_info *mtd)
 	if (ret) {
 		dev_err(&mtd->dev, "mtd%d register to psblk failed\n",
 				mtd->index);
-		return;
+		goto free_badmap;
 	}
 	cxt->mtd = mtd;
 	dev_info(&mtd->dev, "Attached to MTD device %d\n", mtd->index);
+	goto end;
+
+free_badmap:
+	kfree(cxt->badmap);
+free_usedmap:
+	kfree(cxt->usedmap);
+free_rmmap:
+	kfree(cxt->rmmap);
+end:
+	return;
 }
 
 static int mtdpstore_flush_removed_do(struct mtdpstore_context *cxt,
-- 
2.25.1