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video: fbdev: atmel_lcdfb: fix display-timings lookup

PATCH In review Johan Hovold 2 participants 2 messages Nov 13, 2017 – Dec 29, 2017

Subsystems (4)
Stable branch Framebuffer layer Arm/Microchip (AT91) SoC support Microchip lcdfb driver
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Johan Hovold

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#0 lore raw

PATCH 1/1 video: fbdev: atmel_lcdfb: fix display-timings lookup

Fix child-node lookup during probe, which ended up searching the whole device tree depth-first starting at the parent rather than just matching on its children.

To make things worse, the parent display node was also prematurely freed.

Note that the display and timings node references are never put after a successful dt-initialisation so the nodes would leak on later probe deferrals and on driver unbind.

Fixes b985172b328a ("video: atmel_lcdfb: add device tree suport")
Cc stable <[email protected]> # 3.13
Cc Jean-Christophe PLAGNIOL-VILLARD <[email protected]>
Signed-off-by Johan Hovold <[email protected]>
---
 drivers/video/fbdev/atmel_lcdfb.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
drivers/video/fbdev/atmel_lcdfb.c +7 -1
index e06358da4b99..3dee267d7c75 100644
@@ -1119,7 +1119,7 @@ static int atmel_lcdfb_of_init(struct atmel_lcdfb_info *sinfo)
 		goto put_display_node;
 	}
 
-	timings_np = of_find_node_by_name(display_np, "display-timings");
+	timings_np = of_get_child_by_name(display_np, "display-timings");
 	if (!timings_np) {
 		dev_err(dev, "failed to find display-timings node\n");
 		ret = -ENODEV;

@@ -1140,6 +1140,12 @@ static int atmel_lcdfb_of_init(struct atmel_lcdfb_info *sinfo)
 		fb_add_videomode(&fb_vm, &info->modelist);
 	}
 
+	/*
+	 * FIXME: Make sure we are not referencing any fields in display_np
+	 * and timings_np and drop our references to them before returning to
+	 * avoid leaking the nodes on probe deferral and driver unbind.
+	 */
+
 	return 0;
 
 put_timings_node:
Signature · 1 line
2.15.0
#1 lore raw
Quoted 7 lines · Johan Hovold

Fix child-node lookup during probe, which ended up searching the whole device tree depth-first starting at the parent rather than just matching on its children.

To make things worse, the parent display node was also prematurely freed.

Quoted 8 lines

Note that the display and timings node references are never put after a successful dt-initialisation so the nodes would leak on later probe deferrals and on driver unbind.

Fixes b985172b328a ("video: atmel_lcdfb: add device tree suport")
Cc stable <[email protected]> # 3.13
Cc Jean-Christophe PLAGNIOL-VILLARD <[email protected]>
Signed-off-by Johan Hovold <[email protected]>

Patch queued for 4.16, thanks.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics