f:nathan@kernel.org

* [PATCH 2/2] clk: bcm: rpi: Assign ->num before accessing ->hws
  2024-04-25 16:55 96% [PATCH 0/2] clk: bcm: Move a couple of __counted_by initializations Nathan Chancellor
  2024-04-25 16:55 93% ` [PATCH 1/2] clk: bcm: dvp: Assign ->num before accessing ->hws Nathan Chancellor
@ 2024-04-25 16:55 93% ` Nathan Chancellor
  1 sibling, 0 replies; 200+ results
From: Nathan Chancellor @ 2024-04-25 16:55 UTC (permalink / raw)
  To: Michael Turquette, Stephen Boyd, Florian Fainelli
  Cc: Kees Cook, Gustavo A. R. Silva, bcm-kernel-feedback-list,
	linux-clk, linux-rpi-kernel, linux-arm-kernel, linux-hardening,
	patches, llvm, stable, Nathan Chancellor

Commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with
__counted_by") annotated the hws member of 'struct clk_hw_onecell_data'
with __counted_by, which informs the bounds sanitizer about the number
of elements in hws, so that it can warn when hws is accessed out of
bounds. As noted in that change, the __counted_by member must be
initialized with the number of elements before the first array access
happens, otherwise there will be a warning from each access prior to the
initialization because the number of elements is zero. This occurs in
raspberrypi_discover_clocks() due to ->num being assigned after ->hws
has been accessed:

  UBSAN: array-index-out-of-bounds in drivers/clk/bcm/clk-raspberrypi.c:374:4
  index 3 is out of range for type 'struct clk_hw *[] __counted_by(num)' (aka 'struct clk_hw *[]')

Move the ->num initialization to before the first access of ->hws, which
clears up the warning.

Cc: stable@vger.kernel.org
Fixes: f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/clk/bcm/clk-raspberrypi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/bcm/clk-raspberrypi.c b/drivers/clk/bcm/clk-raspberrypi.c
index 829406dc44a2..4d411408e4af 100644
--- a/drivers/clk/bcm/clk-raspberrypi.c
+++ b/drivers/clk/bcm/clk-raspberrypi.c
@@ -371,8 +371,8 @@ static int raspberrypi_discover_clocks(struct raspberrypi_clk *rpi,
 			if (IS_ERR(hw))
 				return PTR_ERR(hw);
 
-			data->hws[clks->id] = hw;
 			data->num = clks->id + 1;
+			data->hws[clks->id] = hw;
 		}
 
 		clks++;

-- 
2.44.0


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