A new warning in Clang 22 [1] complains that @clidr passed to get_clidr_el1() is an uninitialized const pointer. get_clidr_el1() doesn't really care since it casts away the const-ness anyways -- it is a false positive.
| ../arch/arm64/kvm/sys_regs.c:2978:23: warning: variable 'clidr' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer] | 2978 | get_clidr_el1(NULL, &clidr); /* Ugly... */ | | ^~~~~
Disable this warning for sys_regs.o with an iron fist as it doesn't make sense to waste maintainer's time or potentially break builds by backporting large changelists from 6.2+.
This patch isn't needed for anything past 6.1 as this code section was reworked in Commit 7af0c2534f4c ("KVM: arm64: Normalize cache configuration").
Cc: stable@vger.kernel.org Fixes: 7c8c5e6a9101e ("arm64: KVM: system register handling") Link: https://github.com/llvm/llvm-project/commit/00dacf8c22f065cb52efb14cd091d441... [1] Signed-off-by: Justin Stitt justinstitt@google.com --- I've sent a similar patch for 5.15. --- arch/arm64/kvm/Makefile | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index 5e33c2d4645a..5fdb5331bfad 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -24,6 +24,9 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o pmu.o
+# Work around a false positive Clang 22 -Wuninitialized-const-pointer warning +CFLAGS_sys_regs.o := $(call cc-disable-warning, uninitialized-const-pointer) + always-y := hyp_constants.h hyp-constants.s
define rule_gen_hyp_constants
--- base-commit: 830b3c68c1fb1e9176028d02ef86f3cf76aa2476 change-id: 20250728-stable-disable-unit-ptr-warn-281fee82539c
Best regards, -- Justin Stitt justinstitt@google.com
[ Sasha's backport helper bot ]
Hi,
Summary of potential issues: ⚠️ Could not find matching upstream commit
No upstream commit was identified. Using temporary commit for testing.
Results of testing on various branches:
| Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | origin/linux-6.1.y | Success | Success |
On Mon, Jul 28, 2025 at 02:07:36PM -0700, Justin Stitt wrote:
A new warning in Clang 22 [1] complains that @clidr passed to get_clidr_el1() is an uninitialized const pointer. get_clidr_el1() doesn't really care since it casts away the const-ness anyways -- it is a false positive.
| ../arch/arm64/kvm/sys_regs.c:2978:23: warning: variable 'clidr' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer] | 2978 | get_clidr_el1(NULL, &clidr); /* Ugly... */ | | ^~~~~
Disable this warning for sys_regs.o with an iron fist as it doesn't make sense to waste maintainer's time or potentially break builds by backporting large changelists from 6.2+.
This patch isn't needed for anything past 6.1 as this code section was reworked in Commit 7af0c2534f4c ("KVM: arm64: Normalize cache configuration").
Cc: stable@vger.kernel.org Fixes: 7c8c5e6a9101e ("arm64: KVM: system register handling") Link: https://github.com/llvm/llvm-project/commit/00dacf8c22f065cb52efb14cd091d441... [1] Signed-off-by: Justin Stitt justinstitt@google.com
Yes, I think this is an appropriate way to address this for stable.
Reviewed-by: Nathan Chancellor nathan@kernel.org
arch/arm64/kvm/Makefile | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index 5e33c2d4645a..5fdb5331bfad 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -24,6 +24,9 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \ kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o pmu.o +# Work around a false positive Clang 22 -Wuninitialized-const-pointer warning +CFLAGS_sys_regs.o := $(call cc-disable-warning, uninitialized-const-pointer)
always-y := hyp_constants.h hyp-constants.s define rule_gen_hyp_constants
base-commit: 830b3c68c1fb1e9176028d02ef86f3cf76aa2476 change-id: 20250728-stable-disable-unit-ptr-warn-281fee82539c
Best regards,
Justin Stitt justinstitt@google.com
linux-stable-mirror@lists.linaro.org
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