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From: "Uwe Kleine-König" <u.kleine-koenig@baylibre.com>
To: devicetree-compiler@vger.kernel.org
Cc: Rob Herring <robh@kernel.org>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	"Saravana Kannan" <saravanak@google.com>,
	devicetree@vger.kernel.org
Subject: [PATCH] libfdt: overlay: Fix phandle overwrite check for new subtrees
Date: Wed, 26 Jun 2024 09:55:52 +0200	[thread overview]
Message-ID: <20240626075551.2493048-2-u.kleine-koenig@baylibre.com> (raw)

If the overlay's target is only created in a previous fragment, it
doesn't exist in the unmodified base device tree. For the phandle
overwrite check this can be ignored because in this case the base tree
doesn't contain a phandle that could be overwritten.

Adapt the corresponding check to not error out if that happens but just
continue with the next fragment.

This is currently triggered by
arch/arm64/boot/dts/renesas/salvator-panel-aa104xd12.dtso in the kernel
repository which creates /panel in its first fragment and modifies it in
its second.

Reported-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/all/CAL_JsqL9MPycDjqQfPNAuGfC6EMrdzUivr+fuOS7YgU3biGd4A@mail.gmail.com/
Fixes: 1fad065080e6 ("libfdt: overlay: ensure that existing phandles are not overwritten")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
---
 libfdt/fdt_overlay.c                | 8 +++++++-
 tests/overlay_overlay_bypath.dts    | 4 ++++
 tests/overlay_overlay_no_fixups.dts | 8 ++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/libfdt/fdt_overlay.c b/libfdt/fdt_overlay.c
index e19506fb56a5..28b667ffc490 100644
--- a/libfdt/fdt_overlay.c
+++ b/libfdt/fdt_overlay.c
@@ -729,7 +729,13 @@ static int overlay_prevent_phandle_overwrite(void *fdt, void *fdto)
 			return overlay;
 
 		target = fdt_overlay_target_offset(fdt, fdto, fragment, NULL);
-		if (target < 0)
+		if (target == -FDT_ERR_NOTFOUND)
+			/*
+			 * The subtree doesn't exist in the base, so nothing
+			 * will be overwritten.
+			 */
+			continue;
+		else if (target < 0)
 			return target;
 
 		ret = overlay_prevent_phandle_overwrite_node(fdt, target,
diff --git a/tests/overlay_overlay_bypath.dts b/tests/overlay_overlay_bypath.dts
index f23e7b6035e2..dfcb7cdb25a4 100644
--- a/tests/overlay_overlay_bypath.dts
+++ b/tests/overlay_overlay_bypath.dts
@@ -46,3 +46,7 @@
 		new-sub-test-property;
 	};
 };
+
+&{/new-local-node} {
+	another-new-property;
+};
diff --git a/tests/overlay_overlay_no_fixups.dts b/tests/overlay_overlay_no_fixups.dts
index e8d0f96d889c..1dbdcdc2b40f 100644
--- a/tests/overlay_overlay_no_fixups.dts
+++ b/tests/overlay_overlay_no_fixups.dts
@@ -72,6 +72,14 @@
 		};
 	};
 
+	fragment@7 {
+		target-path = "/new-local-node";
+
+		__overlay__ {
+			another-new-property;
+		};
+	};
+
 	__local_fixups__ {
 		fragment@5 {
 			__overlay__ {

base-commit: ff4f17eb58650784ffb2e8a8fbefebce1038f80b
-- 
2.43.0


             reply	other threads:[~2024-06-26  7:56 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-26  7:55 Uwe Kleine-König [this message]
2024-07-02 13:44 ` [PATCH] libfdt: overlay: Fix phandle overwrite check for new subtrees Uwe Kleine-König
2024-07-03 17:06   ` Rob Herring
2024-07-05 11:49     ` David Gibson
2024-07-05 20:53       ` Uwe Kleine-König
2024-07-05 23:46 ` David Gibson

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