linux-kernel - [PATCH 5.12 094/161] wireguard: do not use -O3

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Date:   Tue,  8 Jun 2021 20:27:04 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        "Jason A. Donenfeld" <Jason@...c4.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 5.12 094/161] wireguard: do not use -O3

From: Jason A. Donenfeld <Jason@...c4.com>

commit cc5060ca0285efe2728bced399a1955a7ce808b2 upstream.

Apparently, various versions of gcc have O3-related miscompiles. Looking
at the difference between -O2 and -O3 for gcc 11 doesn't indicate
miscompiles, but the difference also doesn't seem so significant for
performance that it's worth risking.

Link: https://lore.kernel.org/lkml/CAHk-=wjuoGyxDhAF8SsrTkN0-YfCx7E6jUN3ikC_tn2AKWTTsA@mail.gmail.com/
Link: https://lore.kernel.org/lkml/CAHmME9otB5Wwxp7H8bR_i2uH2esEMvoBMC8uEXBMH9p0q1s6Bw@mail.gmail.com/
Reported-by: Linus Torvalds <torvalds@...ux-foundation.org>
Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Cc: stable@...r.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@...c4.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/net/wireguard/Makefile |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/net/wireguard/Makefile
+++ b/drivers/net/wireguard/Makefile
@@ -1,5 +1,4 @@
-ccflags-y := -O3
-ccflags-y += -D'pr_fmt(fmt)=KBUILD_MODNAME ": " fmt'
+ccflags-y := -D'pr_fmt(fmt)=KBUILD_MODNAME ": " fmt'
 ccflags-$(CONFIG_WIREGUARD_DEBUG) += -DDEBUG
 wireguard-y := main.o
 wireguard-y += noise.o