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[PATCH v4 7/9] rocker: fix rocker_tlv_put_* functions for KASAN

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Inlining these functions creates lots of stack variables that each take
64 bytes when KASAN is enabled, leading to this warning about potential
stack overflow:

drivers/net/ethernet/rocker/rocker_ofdpa.c: In function 'ofdpa_cmd_flow_tbl_add':
drivers/net/ethernet/rocker/rocker_ofdpa.c:621:1: error: the frame size of 2752 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

gcc-8 can now consolidate the stack slots itself, but on older versions
we get the same behavior by using a temporary variable that holds a
copy of the inline function argument.

Cc: stable@vger.kernel.org
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/ethernet/rocker/rocker_tlv.h | 48 ++++++++++++++++++++------------
 1 file changed, 30 insertions(+), 18 deletions(-)

diff --git a/drivers/net/ethernet/rocker/rocker_tlv.h b/drivers/net/ethernet/rocker/rocker_tlv.h
index a63ef82e7c72..dfae3c9d57c6 100644
--- a/drivers/net/ethernet/rocker/rocker_tlv.h
+++ b/drivers/net/ethernet/rocker/rocker_tlv.h
@@ -139,40 +139,52 @@ rocker_tlv_start(struct rocker_desc_info *desc_info)
 int rocker_tlv_put(struct rocker_desc_info *desc_info,
 		   int attrtype, int attrlen, const void *data);
 
-static inline int rocker_tlv_put_u8(struct rocker_desc_info *desc_info,
-				    int attrtype, u8 value)
+static inline int
+rocker_tlv_put_u8(struct rocker_desc_info *desc_info, int attrtype, u8 value)
 {
-	return rocker_tlv_put(desc_info, attrtype, sizeof(u8), &value);
+	u8 tmp = value; /* work around GCC PR81715 */
+
+	return rocker_tlv_put(desc_info, attrtype, sizeof(u8), &tmp);
 }
 
-static inline int rocker_tlv_put_u16(struct rocker_desc_info *desc_info,
-				     int attrtype, u16 value)
+static inline int
+rocker_tlv_put_u16(struct rocker_desc_info *desc_info, int attrtype, u16 value)
 {
-	return rocker_tlv_put(desc_info, attrtype, sizeof(u16), &value);
+	u16 tmp = value;
+
+	return rocker_tlv_put(desc_info, attrtype, sizeof(u16), &tmp);
 }
 
-static inline int rocker_tlv_put_be16(struct rocker_desc_info *desc_info,
-				      int attrtype, __be16 value)
+static inline int
+rocker_tlv_put_be16(struct rocker_desc_info *desc_info, int attrtype, __be16 value)
 {
-	return rocker_tlv_put(desc_info, attrtype, sizeof(__be16), &value);
+	__be16 tmp = value;
+
+	return rocker_tlv_put(desc_info, attrtype, sizeof(__be16), &tmp);
 }
 
-static inline int rocker_tlv_put_u32(struct rocker_desc_info *desc_info,
-				     int attrtype, u32 value)
+static inline int
+rocker_tlv_put_u32(struct rocker_desc_info *desc_info, int attrtype, u32 value)
 {
-	return rocker_tlv_put(desc_info, attrtype, sizeof(u32), &value);
+	u32 tmp = value;
+
+	return rocker_tlv_put(desc_info, attrtype, sizeof(u32), &tmp);
 }
 
-static inline int rocker_tlv_put_be32(struct rocker_desc_info *desc_info,
-				      int attrtype, __be32 value)
+static inline int
+rocker_tlv_put_be32(struct rocker_desc_info *desc_info, int attrtype, __be32 value)
 {
-	return rocker_tlv_put(desc_info, attrtype, sizeof(__be32), &value);
+	__be32 tmp = value;
+
+	return rocker_tlv_put(desc_info, attrtype, sizeof(__be32), &tmp);
 }
 
-static inline int rocker_tlv_put_u64(struct rocker_desc_info *desc_info,
-				     int attrtype, u64 value)
+static inline int
+rocker_tlv_put_u64(struct rocker_desc_info *desc_info, int attrtype, u64 value)
 {
-	return rocker_tlv_put(desc_info, attrtype, sizeof(u64), &value);
+	u64 tmp = value;
+
+	return rocker_tlv_put(desc_info, attrtype, sizeof(u64), &tmp);
 }
 
 static inline struct rocker_tlv *
-- 
2.9.0

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[PATCH v4 7/9] rocker: fix rocker_tlv_put_* functions for KASAN Arnd Bergmann <arnd@arndb.de> - 2017-09-22 23:40 +0200
  Re: [PATCH v4 7/9] rocker: fix rocker_tlv_put_* functions for KASAN David Miller <davem@davemloft.net> - 2017-09-26 05:30 +0200

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