From: Arnd Bergmann <arnd@arndb.de>
To: Hans Verkuil <hans.verkuil@cisco.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
Mark Brown <broonie@kernel.org>,
Nathan Chancellor <natechancellor@gmail.com>,
Arnd Bergmann <arnd@arndb.de>,
Dafna Hirschfeld <dafna3@gmail.com>,
Tom aan de Wiel <tom.aandewiel@gmail.com>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/3] media: vicodec: avoic clang frame size warning
Date: Tue, 19 Feb 2019 18:01:57 +0100 [thread overview]
Message-ID: <20190219170209.4180739-2-arnd@arndb.de> (raw)
In-Reply-To: <20190219170209.4180739-1-arnd@arndb.de>
Clang-9 makes some different inlining decisions compared to gcc, which
leads to a warning about a possible stack overflow problem when building
with CONFIG_KASAN, including when setting asan-stack=0, which avoids
most other frame overflow warnings:
drivers/media/platform/vicodec/codec-fwht.c:673:12: error: stack frame size of 2224 bytes in function 'encode_plane'
Manually adding noinline_for_stack annotations in those functions
called by encode_plane() or decode_plane() that require a significant
amount of kernel stack makes this impossible to happen with any
compiler.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/media/platform/vicodec/codec-fwht.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/drivers/media/platform/vicodec/codec-fwht.c b/drivers/media/platform/vicodec/codec-fwht.c
index d1d6085da9f1..135d56bcc2c5 100644
--- a/drivers/media/platform/vicodec/codec-fwht.c
+++ b/drivers/media/platform/vicodec/codec-fwht.c
@@ -47,7 +47,7 @@ static const uint8_t zigzag[64] = {
};
-static int rlc(const s16 *in, __be16 *output, int blocktype)
+static int noinline_for_stack rlc(const s16 *in, __be16 *output, int blocktype)
{
s16 block[8 * 8];
s16 *wp = block;
@@ -106,8 +106,8 @@ static int rlc(const s16 *in, __be16 *output, int blocktype)
* This function will worst-case increase rlc_in by 65*2 bytes:
* one s16 value for the header and 8 * 8 coefficients of type s16.
*/
-static u16 derlc(const __be16 **rlc_in, s16 *dwht_out,
- const __be16 *end_of_input)
+static noinline_for_stack u16
+derlc(const __be16 **rlc_in, s16 *dwht_out, const __be16 *end_of_input)
{
/* header */
const __be16 *input = *rlc_in;
@@ -373,7 +373,8 @@ static void fwht(const u8 *block, s16 *output_block, unsigned int stride,
* Furthermore values can be negative... This is just a version that
* works with 16 signed data
*/
-static void fwht16(const s16 *block, s16 *output_block, int stride, int intra)
+static void noinline_for_stack
+fwht16(const s16 *block, s16 *output_block, int stride, int intra)
{
/* we'll need more than 8 bits for the transformed coefficients */
s32 workspace1[8], workspace2[8];
@@ -456,7 +457,8 @@ static void fwht16(const s16 *block, s16 *output_block, int stride, int intra)
}
}
-static void ifwht(const s16 *block, s16 *output_block, int intra)
+static noinline_for_stack void
+ifwht(const s16 *block, s16 *output_block, int intra)
{
/*
* we'll need more than 8 bits for the transformed coefficients
@@ -604,9 +606,9 @@ static int var_inter(const s16 *old, const s16 *new)
return ret;
}
-static int decide_blocktype(const u8 *cur, const u8 *reference,
- s16 *deltablock, unsigned int stride,
- unsigned int input_step)
+static noinline_for_stack int
+decide_blocktype(const u8 *cur, const u8 *reference, s16 *deltablock,
+ unsigned int stride, unsigned int input_step)
{
s16 tmp[64];
s16 old[64];
--
2.20.0
next prev parent reply other threads:[~2019-02-19 17:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-19 17:01 [PATCH 1/3] media: saa7146: avoid high stack usage with clang Arnd Bergmann
2019-02-19 17:01 ` Arnd Bergmann [this message]
2019-02-19 19:01 ` [PATCH 2/3] media: vicodec: avoic clang frame size warning Nick Desaulniers
2019-02-19 19:14 ` Arnd Bergmann
2019-02-19 19:56 ` Hans Verkuil
2019-02-19 17:01 ` [PATCH 3/3] media: go7007: avoid clang frame overflow warning with KASAN Arnd Bergmann
2019-02-19 18:41 ` [PATCH 1/3] media: saa7146: avoid high stack usage with clang Nick Desaulniers
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