From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
Sasha Levin <sashal@kernel.org>,
christophe.leroy@csgroup.eu, ast@kernel.org,
peterz@infradead.org, paulus@ozlabs.org, npiggin@gmail.com,
dja@axtens.net, masahiroy@kernel.org, aneesh.kumar@linux.ibm.com,
linuxppc-dev@lists.ozlabs.org
Subject: [PATCH AUTOSEL 5.18 04/10] powerpc/64s: Disable stack variable initialisation for prom_init
Date: Mon, 1 Aug 2022 15:02:16 -0400 [thread overview]
Message-ID: <20220801190222.3818378-4-sashal@kernel.org> (raw)
In-Reply-To: <20220801190222.3818378-1-sashal@kernel.org>
From: Michael Ellerman <mpe@ellerman.id.au>
[ Upstream commit be640317a1d0b9cf42fedb2debc2887a7cfa38de ]
With GCC 12 allmodconfig prom_init fails to build:
Error: External symbol 'memset' referenced from prom_init.c
make[2]: *** [arch/powerpc/kernel/Makefile:204: arch/powerpc/kernel/prom_init_check] Error 1
The allmodconfig build enables KASAN, so all calls to memset in
prom_init should be converted to __memset by the #ifdefs in
asm/string.h, because prom_init must use the non-KASAN instrumented
versions.
The build failure happens because there's a call to memset that hasn't
been caught by the pre-processor and converted to __memset. Typically
that's because it's a memset generated by the compiler itself, and that
is the case here.
With GCC 12, allmodconfig enables CONFIG_INIT_STACK_ALL_PATTERN, which
causes the compiler to emit memset calls to initialise on-stack
variables with a pattern.
Because prom_init is non-user-facing boot-time only code, as a
workaround just disable stack variable initialisation to unbreak the
build.
Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220718134418.354114-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kernel/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 4ddd161aef32..63c384c3e6d4 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -20,6 +20,7 @@ CFLAGS_prom.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
CFLAGS_prom_init.o += -fno-stack-protector
CFLAGS_prom_init.o += -DDISABLE_BRANCH_PROFILING
CFLAGS_prom_init.o += -ffreestanding
+CFLAGS_prom_init.o += $(call cc-option, -ftrivial-auto-var-init=uninitialized)
ifdef CONFIG_FUNCTION_TRACER
# Do not trace early boot code
--
2.35.1
WARNING: multiple messages have this Message-ID (diff)
From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
peterz@infradead.org, masahiroy@kernel.org, ast@kernel.org,
npiggin@gmail.com, aneesh.kumar@linux.ibm.com,
linuxppc-dev@lists.ozlabs.org,
Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
dja@axtens.net
Subject: [PATCH AUTOSEL 5.18 04/10] powerpc/64s: Disable stack variable initialisation for prom_init
Date: Mon, 1 Aug 2022 15:02:16 -0400 [thread overview]
Message-ID: <20220801190222.3818378-4-sashal@kernel.org> (raw)
In-Reply-To: <20220801190222.3818378-1-sashal@kernel.org>
From: Michael Ellerman <mpe@ellerman.id.au>
[ Upstream commit be640317a1d0b9cf42fedb2debc2887a7cfa38de ]
With GCC 12 allmodconfig prom_init fails to build:
Error: External symbol 'memset' referenced from prom_init.c
make[2]: *** [arch/powerpc/kernel/Makefile:204: arch/powerpc/kernel/prom_init_check] Error 1
The allmodconfig build enables KASAN, so all calls to memset in
prom_init should be converted to __memset by the #ifdefs in
asm/string.h, because prom_init must use the non-KASAN instrumented
versions.
The build failure happens because there's a call to memset that hasn't
been caught by the pre-processor and converted to __memset. Typically
that's because it's a memset generated by the compiler itself, and that
is the case here.
With GCC 12, allmodconfig enables CONFIG_INIT_STACK_ALL_PATTERN, which
causes the compiler to emit memset calls to initialise on-stack
variables with a pattern.
Because prom_init is non-user-facing boot-time only code, as a
workaround just disable stack variable initialisation to unbreak the
build.
Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220718134418.354114-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kernel/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 4ddd161aef32..63c384c3e6d4 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -20,6 +20,7 @@ CFLAGS_prom.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
CFLAGS_prom_init.o += -fno-stack-protector
CFLAGS_prom_init.o += -DDISABLE_BRANCH_PROFILING
CFLAGS_prom_init.o += -ffreestanding
+CFLAGS_prom_init.o += $(call cc-option, -ftrivial-auto-var-init=uninitialized)
ifdef CONFIG_FUNCTION_TRACER
# Do not trace early boot code
--
2.35.1
next prev parent reply other threads:[~2022-08-01 19:02 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-01 19:02 [PATCH AUTOSEL 5.18 01/10] pinctrl: Don't allow PINCTRL_AMD to be a module Sasha Levin
2022-08-01 19:02 ` [PATCH AUTOSEL 5.18 02/10] drm/amdgpu: Remove one duplicated ef removal Sasha Levin
2022-08-01 19:02 ` Sasha Levin
2022-08-01 19:02 ` Sasha Levin
2022-08-01 19:02 ` [PATCH AUTOSEL 5.18 03/10] ntfs: fix use-after-free in ntfs_ucsncmp() Sasha Levin
2022-08-01 19:02 ` Sasha Levin [this message]
2022-08-01 19:02 ` [PATCH AUTOSEL 5.18 04/10] powerpc/64s: Disable stack variable initialisation for prom_init Sasha Levin
2022-08-01 19:02 ` [PATCH AUTOSEL 5.18 05/10] spi: spi-rspi: Fix PIO fallback on RZ platforms Sasha Levin
2022-08-01 19:02 ` [PATCH AUTOSEL 5.18 06/10] mmu_gather: Let there be one tlb_{start,end}_vma() implementation Sasha Levin
2022-08-01 19:02 ` [PATCH AUTOSEL 5.18 07/10] mmu_gather: Force tlb-flush VM_PFNMAP vmas Sasha Levin
2022-08-01 19:02 ` [PATCH AUTOSEL 5.18 08/10] netfilter: nf_tables: add rescheduling points during loop detection walks Sasha Levin
2022-08-01 19:02 ` [PATCH AUTOSEL 5.18 09/10] netfilter: nft_queue: only allow supported familes and hooks Sasha Levin
2022-08-01 19:02 ` [PATCH AUTOSEL 5.18 10/10] ARM: findbit: fix overflowing offset Sasha Levin
2022-08-01 19:02 ` Sasha Levin
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