From 418c85ea458a01522a2a61f5fd111043940b8e4e Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 15 Mar 2018 17:19:57 +0100 Subject: [PATCH] gpu: ipu-v3: prg: avoid possible array underflow [ Upstream commit 746d024c3211813946b319411aeb2b47767f8fb0 ] gcc-8 reports that we access an array with a negative index in an error case: drivers/gpu/ipu-v3/ipu-prg.c: In function 'ipu_prg_channel_disable': drivers/gpu/ipu-v3/ipu-prg.c:252:43: error: array subscript -22 is below array bounds of 'struct ipu_prg_channel[3]' [-Werror=array-bounds] This moves the range check in front of the first time that variable gets used. Signed-off-by: Arnd Bergmann Signed-off-by: Philipp Zabel Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/ipu-v3/ipu-prg.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/ipu-v3/ipu-prg.c b/drivers/gpu/ipu-v3/ipu-prg.c index cbccce8e594b..1c36fa3a90e2 100644 --- a/drivers/gpu/ipu-v3/ipu-prg.c +++ b/drivers/gpu/ipu-v3/ipu-prg.c @@ -252,10 +252,14 @@ void ipu_prg_channel_disable(struct ipuv3_channel *ipu_chan) { int prg_chan = ipu_prg_ipu_to_prg_chan(ipu_chan->num); struct ipu_prg *prg = ipu_chan->ipu->prg_priv; - struct ipu_prg_channel *chan = &prg->chan[prg_chan]; + struct ipu_prg_channel *chan; u32 val; - if (!chan->enabled || prg_chan < 0) + if (prg_chan < 0) + return; + + chan = &prg->chan[prg_chan]; + if (!chan->enabled) return; clk_prepare_enable(prg->clk_ipg); @@ -282,13 +286,15 @@ int ipu_prg_channel_configure(struct ipuv3_channel *ipu_chan, { int prg_chan = ipu_prg_ipu_to_prg_chan(ipu_chan->num); struct ipu_prg *prg = ipu_chan->ipu->prg_priv; - struct ipu_prg_channel *chan = &prg->chan[prg_chan]; + struct ipu_prg_channel *chan; u32 val; int ret; if (prg_chan < 0) return prg_chan; + chan = &prg->chan[prg_chan]; + if (chan->enabled) { ipu_pre_update(prg->pres[chan->used_pre], *eba); return 0; -- 2.20.1