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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Peter Suti <peter.suti@streamunlimited.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.18 0796/1095] staging: fbtft: core: set smem_len before fb_deferred_io_init call
Date:   Mon, 15 Aug 2022 20:03:15 +0200
Message-Id: <20220815180502.179602518@linuxfoundation.org>
In-Reply-To: <20220815180429.240518113@linuxfoundation.org>
References: <20220815180429.240518113@linuxfoundation.org>
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From: Peter Suti <peter.suti@streamunlimited.com>

[ Upstream commit 81e878887ff82a7dd42f22951391069a5d520627 ]

The fbtft_framebuffer_alloc() calls fb_deferred_io_init() before
initializing info->fix.smem_len.  It is set to zero by the
framebuffer_alloc() function.  It will trigger a WARN_ON() at the
start of fb_deferred_io_init() and the function will not do anything.

Fixes: 856082f021a2 ("fbdev: defio: fix the pagelist corruption")
Signed-off-by: Peter Suti <peter.suti@streamunlimited.com>
Link: https://lore.kernel.org/r/20220727073550.1491126-1-peter.suti@streamunlimited.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/staging/fbtft/fbtft-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index 9c4d797e7ae4..4137c1a51e1b 100644
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -656,7 +656,6 @@ struct fb_info *fbtft_framebuffer_alloc(struct fbtft_display *display,
 	fbdefio->delay =           HZ / fps;
 	fbdefio->sort_pagelist =   true;
 	fbdefio->deferred_io =     fbtft_deferred_io;
-	fb_deferred_io_init(info);
 
 	snprintf(info->fix.id, sizeof(info->fix.id), "%s", dev->driver->name);
 	info->fix.type =           FB_TYPE_PACKED_PIXELS;
@@ -667,6 +666,7 @@ struct fb_info *fbtft_framebuffer_alloc(struct fbtft_display *display,
 	info->fix.line_length =    width * bpp / 8;
 	info->fix.accel =          FB_ACCEL_NONE;
 	info->fix.smem_len =       vmem_size;
+	fb_deferred_io_init(info);
 
 	info->var.rotate =         pdata->rotate;
 	info->var.xres =           width;
-- 
2.35.1