[added,to,the,4.1,stable,tree] mtd: ichxrom: maybe-uninitialized with gcc-4.9

Message ID 20180301152116.1486-447-alexander.levin@microsoft.com
State New
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  • [added,to,the,4.1,stable,tree] mtd: ichxrom: maybe-uninitialized with gcc-4.9
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Commit Message

Sasha Levin March 1, 2018, 3:27 p.m.
From: Arnd Bergmann <arnd@arndb.de>


This patch has been added to the 4.1 stable tree. If you have any
objections, please let us know.

-- 
2.14.1

Patch

===============

[ Upstream commit e70dda0868fad0f74c46df21f7f45fec24f29879 ]

pci_read_config_word() might fail and not initialize its output,
as pointed out by older versions of gcc when using the -Wmaybe-unintialized
flag:

drivers/mtd/maps/ichxrom.c: In function ‘ichxrom_cleanup’:
drivers/mtd/maps/ichxrom.c:63:2: error: ‘word’ is used uninitialized in this function [-Werror=uninitialized]

This is apparently a correct warning, though it does not show up
with newer compilers. Changing the code to not attempt to write
back uninitialized data into PCI config space is a correct
fix for the problem and avoids the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/mtd/maps/ichxrom.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/maps/ichxrom.c b/drivers/mtd/maps/ichxrom.c
index c7478e18f485..2fb2d0ec3367 100644
--- a/drivers/mtd/maps/ichxrom.c
+++ b/drivers/mtd/maps/ichxrom.c
@@ -57,10 +57,12 @@  static void ichxrom_cleanup(struct ichxrom_window *window)
 {
 	struct ichxrom_map_info *map, *scratch;
 	u16 word;
+	int ret;
 
 	/* Disable writes through the rom window */
-	pci_read_config_word(window->pdev, BIOS_CNTL, &word);
-	pci_write_config_word(window->pdev, BIOS_CNTL, word & ~1);
+	ret = pci_read_config_word(window->pdev, BIOS_CNTL, &word);
+	if (!ret)
+		pci_write_config_word(window->pdev, BIOS_CNTL, word & ~1);
 	pci_dev_put(window->pdev);
 
 	/* Free all of the mtd devices */