linux-kernel - [PATCH 4.18 175/350] firmware: coreboot: Unmap ioregion after device population

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Date:   Sun, 11 Nov 2018 14:20:39 -0800
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Wei-Ning Huang <wnhuang@...omium.org>,
        Julius Werner <jwerner@...omium.org>,
        Brian Norris <briannorris@...omium.org>,
        Samuel Holland <samuel@...lland.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.18 175/350] firmware: coreboot: Unmap ioregion after device population

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stephen Boyd <swboyd@...omium.org>

[ Upstream commit 20edec388277b62ddfddb8b2b376a937a2cd6d1b ]

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>
Reviewed-by: Julius Werner <jwerner@...omium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/firmware/google/coreboot_table.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/firmware/google/coreboot_table.c
+++ b/drivers/firmware/google/coreboot_table.c
@@ -110,7 +110,8 @@ int coreboot_table_init(struct device *d
 
 	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 *d
 
 		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;
 	}