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authorArnd Bergmann <arnd@arndb.de>2017-02-03 17:35:46 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-02-14 15:22:51 -0800
commitcc187c6200f8316cc211d77fc35f269e7135fab4 (patch)
tree5ee70f5ec91cdcc54f5fd3a28c8b6929d70cde98 /drivers/net
parent3b7ff5ed114fdb65517ee564a717b9c5fa374c94 (diff)
downloadlinux-linaro-stable-cc187c6200f8316cc211d77fc35f269e7135fab4.tar.gz
hns: avoid stack overflow with CONFIG_KASAN
commit b3f2d07f4649adcf6905953a10d217b5683e4077 upstream. The use of ACCESS_ONCE() looks like a micro-optimization to force gcc to use an indexed load for the register address, but it has an absolutely detrimental effect on builds with gcc-5 and CONFIG_KASAN=y, leading to a very likely kernel stack overflow aside from very complex object code: hisilicon/hns/hns_dsaf_gmac.c: In function 'hns_gmac_update_stats': hisilicon/hns/hns_dsaf_gmac.c:419:1: error: the frame size of 2912 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] hisilicon/hns/hns_dsaf_ppe.c: In function 'hns_ppe_reset_common': hisilicon/hns/hns_dsaf_ppe.c:390:1: error: the frame size of 1184 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] hisilicon/hns/hns_dsaf_ppe.c: In function 'hns_ppe_get_regs': hisilicon/hns/hns_dsaf_ppe.c:621:1: error: the frame size of 3632 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] hisilicon/hns/hns_dsaf_rcb.c: In function 'hns_rcb_get_common_regs': hisilicon/hns/hns_dsaf_rcb.c:970:1: error: the frame size of 2784 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] hisilicon/hns/hns_dsaf_gmac.c: In function 'hns_gmac_get_regs': hisilicon/hns/hns_dsaf_gmac.c:641:1: error: the frame size of 5728 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] hisilicon/hns/hns_dsaf_rcb.c: In function 'hns_rcb_get_ring_regs': hisilicon/hns/hns_dsaf_rcb.c:1021:1: error: the frame size of 2208 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_comm_init': hisilicon/hns/hns_dsaf_main.c:1209:1: error: the frame size of 1904 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] hisilicon/hns/hns_dsaf_xgmac.c: In function 'hns_xgmac_get_regs': hisilicon/hns/hns_dsaf_xgmac.c:748:1: error: the frame size of 4704 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_update_stats': hisilicon/hns/hns_dsaf_main.c:2420:1: error: the frame size of 1088 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_get_regs': hisilicon/hns/hns_dsaf_main.c:2753:1: error: the frame size of 10768 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] This does not seem to happen any more with gcc-7, but removing the ACCESS_ONCE seems safe anyway and it avoids a serious issue for some people. I have verified that with gcc-5.3.1, the object code we get is better in the new version both with and without CONFIG_KASAN, as we no longer allocate a 1344 byte stack frame for hns_dsaf_get_regs() but otherwise have practically identical object code. With gcc-7.0.0, removing ACCESS_ONCE has no effect, the object code is already good either way. This patch is probably not urgent to get into 4.11 as only KASAN=y builds with certain compilers are affected, but I still think it makes sense to backport into older kernels. Fixes: 511e6bc ("net: add Hisilicon Network Subsystem DSAF support") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/ethernet/hisilicon/hns/hns_dsaf_reg.h8
1 files changed, 2 insertions, 6 deletions
diff --git a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_reg.h b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_reg.h
index bdbd80423b17..9ff2881f933d 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_reg.h
+++ b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_reg.h
@@ -900,9 +900,7 @@
static inline void dsaf_write_reg(void __iomem *base, u32 reg, u32 value)
{
- u8 __iomem *reg_addr = ACCESS_ONCE(base);
-
- writel(value, reg_addr + reg);
+ writel(value, base + reg);
}
#define dsaf_write_dev(a, reg, value) \
@@ -910,9 +908,7 @@ static inline void dsaf_write_reg(void __iomem *base, u32 reg, u32 value)
static inline u32 dsaf_read_reg(u8 __iomem *base, u32 reg)
{
- u8 __iomem *reg_addr = ACCESS_ONCE(base);
-
- return readl(reg_addr + reg);
+ return readl(base + reg);
}
#define dsaf_read_dev(a, reg) \