linux-kernel - [PATCH] video: fbdev: w100fb: Reset global state

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Message-Id: <20210811165826.23752-1-novikov@ispras.ru>
Date:   Wed, 11 Aug 2021 19:58:26 +0300
From:   Evgeny Novikov <novikov@...ras.ru>
To:     dri-devel@...ts.freedesktop.org
Cc:     Evgeny Novikov <novikov@...ras.ru>, linux-fbdev@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Kirill Shilimanov <kirill.shilimanov@...wei.com>
Subject: [PATCH] video: fbdev: w100fb: Reset global state

w100fb_probe() did not reset the global state to its initial state. This
can result in invocation of iounmap() even when there was not the
appropriate successful call of ioremap(). For instance, this may be the
case if first probe fails after two successful ioremap() while second
probe fails when first ioremap() fails. The similar issue is with
w100fb_remove(). The patch fixes both bugs.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Evgeny Novikov <novikov@...ras.ru>
Co-developed-by: Kirill Shilimanov <kirill.shilimanov@...wei.com>
Signed-off-by: Kirill Shilimanov <kirill.shilimanov@...wei.com>
---
 drivers/video/fbdev/w100fb.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/video/fbdev/w100fb.c b/drivers/video/fbdev/w100fb.c
index d96ab28f8ce4..4e641a780726 100644
--- a/drivers/video/fbdev/w100fb.c
+++ b/drivers/video/fbdev/w100fb.c
@@ -770,12 +770,18 @@ static int w100fb_probe(struct platform_device *pdev)
 		fb_dealloc_cmap(&info->cmap);
 		kfree(info->pseudo_palette);
 	}
-	if (remapped_fbuf != NULL)
+	if (remapped_fbuf != NULL) {
 		iounmap(remapped_fbuf);
-	if (remapped_regs != NULL)
+		remapped_fbuf = NULL;
+	}
+	if (remapped_regs != NULL) {
 		iounmap(remapped_regs);
-	if (remapped_base != NULL)
+		remapped_regs = NULL;
+	}
+	if (remapped_base != NULL) {
 		iounmap(remapped_base);
+		remapped_base = NULL;
+	}
 	if (info)
 		framebuffer_release(info);
 	return err;
@@ -795,8 +801,11 @@ static int w100fb_remove(struct platform_device *pdev)
 	fb_dealloc_cmap(&info->cmap);
 
 	iounmap(remapped_base);
+	remapped_base = NULL;
 	iounmap(remapped_regs);
+	remapped_regs = NULL;
 	iounmap(remapped_fbuf);
+	remapped_fbuf = NULL;
 
 	framebuffer_release(info);
 
-- 
2.26.2