linux-kernel - [PATCH v4 2/6] firmware: coreboot: Unmap ioregion after device population

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Message-Id: <20180815203708.67090-3-swboyd@chromium.org>
Date:   Wed, 15 Aug 2018 13:37:04 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org,
        Wei-Ning Huang <wnhuang@...omium.org>,
        Julius Werner <jwerner@...omium.org>,
        Brian Norris <briannorris@...omium.org>,
        Samuel Holland <samuel@...lland.org>
Subject: [PATCH v4 2/6] firmware: coreboot: Unmap ioregion after device population

Both callers of coreboot_table_init() ioremap the pointer that comes in
but they don't unmap the memory on failure. Both of them also fail probe
immediately with the return value of coreboot_table_init(), leaking a
mapping when it fails. The mapping isn't necessary at all after devices
are populated either, so we can just drop the mapping here when we exit
the function. Let's do that to simplify the code a bit and plug the leak.

Cc: Wei-Ning Huang <wnhuang@...omium.org>
Cc: Julius Werner <jwerner@...omium.org>
Cc: Brian Norris <briannorris@...omium.org>
Cc: Samuel Holland <samuel@...lland.org>
Fixes: 570d30c2823f ("firmware: coreboot: Expose the coreboot table as a bus")
Signed-off-by: Stephen Boyd <swboyd@...omium.org>
---
 drivers/firmware/google/coreboot_table.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c
index 19db5709ae28..898bb9abc41f 100644
--- a/drivers/firmware/google/coreboot_table.c
+++ b/drivers/firmware/google/coreboot_table.c
@@ -110,7 +110,8 @@ int coreboot_table_init(struct device *dev, void __iomem *ptr)
 
 	if (strncmp(header.signature, "LBIO", sizeof(header.signature))) {
 		pr_warn("coreboot_table: coreboot table missing or corrupt!\n");
-		return -ENODEV;
+		ret = -ENODEV;
+		goto out;
 	}
 
 	ptr_entry = (void *)ptr_header + header.header_bytes;
@@ -137,7 +138,8 @@ int coreboot_table_init(struct device *dev, void __iomem *ptr)
 
 		ptr_entry += entry.size;
 	}
-
+out:
+	iounmap(ptr);
 	return ret;
 }
 EXPORT_SYMBOL(coreboot_table_init);
@@ -146,7 +148,6 @@ int coreboot_table_exit(void)
 {
 	if (ptr_header) {
 		bus_unregister(&coreboot_bus_type);
-		iounmap(ptr_header);
 		ptr_header = NULL;
 	}
 
-- 
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