* Re: Patch "ACPI: APEI: GHES: Disable KASAN instrumentation when compile testing with clang < 18" has been added to the 6.12-stable tree [not found] <20260308164129.19119-1-sashal@kernel.org> @ 2026-03-09 21:28 ` Nathan Chancellor 2026-03-09 22:25 ` Sasha Levin 0 siblings, 1 reply; 2+ messages in thread From: Nathan Chancellor @ 2026-03-09 21:28 UTC (permalink / raw) To: stable, Sasha Levin Cc: stable-commits, Rafael J. Wysocki, Tony Luck, Borislav Petkov, Hanjun Guo, Mauro Carvalho Chehab, Shuai Xue, Len Brown, Nick Desaulniers, Bill Wendling, Justin Stitt On Sun, Mar 08, 2026 at 12:41:28PM -0400, Sasha Levin wrote: > This is a note to let you know that I've just added the patch titled > > ACPI: APEI: GHES: Disable KASAN instrumentation when compile testing with clang < 18 > > to the 6.12-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > acpi-apei-ghes-disable-kasan-instrumentation-when-co.patch > and it can be found in the queue-6.12 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@vger.kernel.org> know about it. > > > > commit ccd3cab8095d5c53eaf8a6598ff339ffaad6a696 > Author: Nathan Chancellor <nathan@kernel.org> > Date: Wed Jan 14 16:27:11 2026 -0700 > > ACPI: APEI: GHES: Disable KASAN instrumentation when compile testing with clang < 18 > > [ Upstream commit b584bfbd7ec417f257f651cc00a90c66e31dfbf1 ] > > After a recent innocuous change to drivers/acpi/apei/ghes.c, building > ARCH=arm64 allmodconfig with clang-17 or older (which has both > CONFIG_KASAN=y and CONFIG_WERROR=y) fails with: > > drivers/acpi/apei/ghes.c:902:13: error: stack frame size (2768) exceeds limit (2048) in 'ghes_do_proc' [-Werror,-Wframe-larger-than] > 902 | static void ghes_do_proc(struct ghes *ghes, > | ^ > > A KASAN pass that removes unneeded stack instrumentation, enabled by > default in clang-18 [1], drastically improves stack usage in this case. > > To avoid the warning in the common allmodconfig case when it can break > the build, disable KASAN for ghes.o when compile testing with clang-17 > and older. Disabling KASAN outright may hide legitimate runtime issues, > so live with the warning in that case; the user can either increase the > frame warning limit or disable -Werror, which they should probably do > when debugging with KASAN anyways. > > Closes: https://github.com/ClangBuiltLinux/linux/issues/2148 > Link: https://github.com/llvm/llvm-project/commit/51fbab134560ece663517bf1e8c2a30300d08f1a [1] > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > Cc: All applicable <stable@vger.kernel.org> > Link: https://patch.msgid.link/20260114-ghes-avoid-wflt-clang-older-than-18-v1-1-9c8248bfe4f4@kernel.org > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > Signed-off-by: Sasha Levin <sashal@kernel.org> > > diff --git a/drivers/acpi/apei/Makefile b/drivers/acpi/apei/Makefile > index 5db61dfb46915..1a0b85923cd42 100644 > --- a/drivers/acpi/apei/Makefile > +++ b/drivers/acpi/apei/Makefile > @@ -1,6 +1,10 @@ > # SPDX-License-Identifier: GPL-2.0 > obj-$(CONFIG_ACPI_APEI) += apei.o > obj-$(CONFIG_ACPI_APEI_GHES) += ghes.o > +# clang versions prior to 18 may blow out the stack with KASAN > +ifeq ($(CONFIG_COMPILE_TEST)_$(CONFIG_CC_IS_CLANG)_$(call clang-min-version, 180000),y_y_) > +KASAN_SANITIZE_ghes.o := n > +endif > obj-$(CONFIG_ACPI_APEI_PCIEAER) += ghes_helpers.o > obj-$(CONFIG_ACPI_APEI_EINJ) += einj.o > einj-y := einj-core.o The backports you have taken to make this apply cleanly to 6.12 20260308164114.18890-1-sashal@kernel.org 20260308164118.18945-1-sashal@kernel.org 20260308164121.19006-1-sashal@kernel.org 20260308164125.19064-1-sashal@kernel.org are excessive in my opinion. I think you should just address the conflict... There is absolutely no dependency on those changes so "Stable-dep-of" is a bit misleading. diff --git a/drivers/acpi/apei/Makefile b/drivers/acpi/apei/Makefile index 2c474e6477e1..346cdf0a0ef9 100644 --- a/drivers/acpi/apei/Makefile +++ b/drivers/acpi/apei/Makefile @@ -1,6 +1,10 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_ACPI_APEI) += apei.o obj-$(CONFIG_ACPI_APEI_GHES) += ghes.o +# clang versions prior to 18 may blow out the stack with KASAN +ifeq ($(CONFIG_COMPILE_TEST)_$(CONFIG_CC_IS_CLANG)_$(call clang-min-version, 180000),y_y_) +KASAN_SANITIZE_ghes.o := n +endif obj-$(CONFIG_ACPI_APEI_EINJ) += einj.o einj-y := einj-core.o einj-$(CONFIG_ACPI_APEI_EINJ_CXL) += einj-cxl.o ^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: Patch "ACPI: APEI: GHES: Disable KASAN instrumentation when compile testing with clang < 18" has been added to the 6.12-stable tree 2026-03-09 21:28 ` Patch "ACPI: APEI: GHES: Disable KASAN instrumentation when compile testing with clang < 18" has been added to the 6.12-stable tree Nathan Chancellor @ 2026-03-09 22:25 ` Sasha Levin 0 siblings, 0 replies; 2+ messages in thread From: Sasha Levin @ 2026-03-09 22:25 UTC (permalink / raw) To: Nathan Chancellor Cc: stable, stable-commits, Rafael J. Wysocki, Tony Luck, Borislav Petkov, Hanjun Guo, Mauro Carvalho Chehab, Shuai Xue, Len Brown, Nick Desaulniers, Bill Wendling, Justin Stitt On Mon, Mar 09, 2026 at 02:28:07PM -0700, Nathan Chancellor wrote: >On Sun, Mar 08, 2026 at 12:41:28PM -0400, Sasha Levin wrote: >> This is a note to let you know that I've just added the patch titled >> >> ACPI: APEI: GHES: Disable KASAN instrumentation when compile testing with clang < 18 >> >> to the 6.12-stable tree which can be found at: >> http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary >> >> The filename of the patch is: >> acpi-apei-ghes-disable-kasan-instrumentation-when-co.patch >> and it can be found in the queue-6.12 subdirectory. >> >> If you, or anyone else, feels it should not be added to the stable tree, >> please let <stable@vger.kernel.org> know about it. >> >> >> >> commit ccd3cab8095d5c53eaf8a6598ff339ffaad6a696 >> Author: Nathan Chancellor <nathan@kernel.org> >> Date: Wed Jan 14 16:27:11 2026 -0700 >> >> ACPI: APEI: GHES: Disable KASAN instrumentation when compile testing with clang < 18 >> >> [ Upstream commit b584bfbd7ec417f257f651cc00a90c66e31dfbf1 ] >> >> After a recent innocuous change to drivers/acpi/apei/ghes.c, building >> ARCH=arm64 allmodconfig with clang-17 or older (which has both >> CONFIG_KASAN=y and CONFIG_WERROR=y) fails with: >> >> drivers/acpi/apei/ghes.c:902:13: error: stack frame size (2768) exceeds limit (2048) in 'ghes_do_proc' [-Werror,-Wframe-larger-than] >> 902 | static void ghes_do_proc(struct ghes *ghes, >> | ^ >> >> A KASAN pass that removes unneeded stack instrumentation, enabled by >> default in clang-18 [1], drastically improves stack usage in this case. >> >> To avoid the warning in the common allmodconfig case when it can break >> the build, disable KASAN for ghes.o when compile testing with clang-17 >> and older. Disabling KASAN outright may hide legitimate runtime issues, >> so live with the warning in that case; the user can either increase the >> frame warning limit or disable -Werror, which they should probably do >> when debugging with KASAN anyways. >> >> Closes: https://github.com/ClangBuiltLinux/linux/issues/2148 >> Link: https://github.com/llvm/llvm-project/commit/51fbab134560ece663517bf1e8c2a30300d08f1a [1] >> Signed-off-by: Nathan Chancellor <nathan@kernel.org> >> Cc: All applicable <stable@vger.kernel.org> >> Link: https://patch.msgid.link/20260114-ghes-avoid-wflt-clang-older-than-18-v1-1-9c8248bfe4f4@kernel.org >> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> >> Signed-off-by: Sasha Levin <sashal@kernel.org> >> >> diff --git a/drivers/acpi/apei/Makefile b/drivers/acpi/apei/Makefile >> index 5db61dfb46915..1a0b85923cd42 100644 >> --- a/drivers/acpi/apei/Makefile >> +++ b/drivers/acpi/apei/Makefile >> @@ -1,6 +1,10 @@ >> # SPDX-License-Identifier: GPL-2.0 >> obj-$(CONFIG_ACPI_APEI) += apei.o >> obj-$(CONFIG_ACPI_APEI_GHES) += ghes.o >> +# clang versions prior to 18 may blow out the stack with KASAN >> +ifeq ($(CONFIG_COMPILE_TEST)_$(CONFIG_CC_IS_CLANG)_$(call clang-min-version, 180000),y_y_) >> +KASAN_SANITIZE_ghes.o := n >> +endif >> obj-$(CONFIG_ACPI_APEI_PCIEAER) += ghes_helpers.o >> obj-$(CONFIG_ACPI_APEI_EINJ) += einj.o >> einj-y := einj-core.o > >The backports you have taken to make this apply cleanly to 6.12 > > 20260308164114.18890-1-sashal@kernel.org > 20260308164118.18945-1-sashal@kernel.org > 20260308164121.19006-1-sashal@kernel.org > 20260308164125.19064-1-sashal@kernel.org > >are excessive in my opinion. I think you should just address the >conflict... There is absolutely no dependency on those changes so >"Stable-dep-of" is a bit misleading. ack -- Thanks, Sasha ^ permalink raw reply [flat|nested] 2+ messages in thread
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2026-03-09 21:28 ` Patch "ACPI: APEI: GHES: Disable KASAN instrumentation when compile testing with clang < 18" has been added to the 6.12-stable tree Nathan Chancellor
2026-03-09 22:25 ` Sasha Levin
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