| Message ID | 6559f36c6c6cdc2552b0bccf31de967367aa790d.1489672478.git.jpoimboe@redhat.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Thu, 16 Mar 2017 08:56:28 -0500 Josh Poimboeuf <jpoimboe@redhat.com> wrote: > Paul Menzel reported a warning: > > WARNING: CPU: 0 PID: 774 at /build/linux-ROBWaj/linux-4.9.13/kernel/trace/trace_functions_graph.c:233 ftrace_return_to_handler+0x1aa/0x1e0 > Bad frame pointer: expected f6919d98, received f6919db0 > from func acpi_pm_device_sleep_wake return to c43b6f9d > > The warning means that function graph tracing is broken for the > acpi_pm_device_sleep_wake() function. That's because the acpi Makefile > unconditionally sets the '-Os' gcc flag to optimize for size. That's an > issue because mcount-based function graph tracing is incompatible with > '-Os' on x86, thanks to the following gcc bug: > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109 > > I have another patch pending which will ensure that mcount-based > function graph tracing is never used with CONFIG_CC_OPTIMIZE_FOR_SIZE on > x86. > > But this patch is needed in addition to that one because the ACPI > Makefile overrides that config option for no apparent reason. It has > had this flag since the beginning of git history, and there's no related > comment, so I don't know why it's there. As far as I can tell, there's > no reason for it to be there. The appropriate behavior is for it to > honor CONFIG_CC_OPTIMIZE_FOR_{SIZE,PERFORMANCE} like the rest of the > kernel. > > Reported-by: Paul Menzel <pmenzel@molgen.mpg.de> > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> > --- > drivers/acpi/Makefile | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile > index a391bbc..d94f92f 100644 > --- a/drivers/acpi/Makefile > +++ b/drivers/acpi/Makefile > @@ -2,7 +2,6 @@ > # Makefile for the Linux ACPI interpreter > # > > -ccflags-y := -Os Unless somebody can come up with a real reason to have this, Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> -- Steve > ccflags-$(CONFIG_ACPI_DEBUG) += -DACPI_DEBUG_OUTPUT > > # -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Dear Josh, On 2017-03-16 14:56, Josh Poimboeuf wrote: > Paul Menzel reported a warning: > > WARNING: CPU: 0 PID: 774 at > /build/linux-ROBWaj/linux-4.9.13/kernel/trace/trace_functions_graph.c:233 > ftrace_return_to_handler+0x1aa/0x1e0 > Bad frame pointer: expected f6919d98, received f6919db0 > from func acpi_pm_device_sleep_wake return to c43b6f9d > > The warning means that function graph tracing is broken for the > acpi_pm_device_sleep_wake() function. That's because the acpi Makefile > unconditionally sets the '-Os' gcc flag to optimize for size. That's > an > issue because mcount-based function graph tracing is incompatible with > '-Os' on x86, thanks to the following gcc bug: > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109 > > I have another patch pending which will ensure that mcount-based > function graph tracing is never used with CONFIG_CC_OPTIMIZE_FOR_SIZE > on > x86. > > But this patch is needed in addition to that one because the ACPI > Makefile overrides that config option for no apparent reason. It has > had this flag since the beginning of git history, and there's no > related > comment, so I don't know why it's there. As far as I can tell, there's > no reason for it to be there. The appropriate behavior is for it to > honor CONFIG_CC_OPTIMIZE_FOR_{SIZE,PERFORMANCE} like the rest of the > kernel. > > Reported-by: Paul Menzel <pmenzel@molgen.mpg.de> > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> > --- > drivers/acpi/Makefile | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile > index a391bbc..d94f92f 100644 > --- a/drivers/acpi/Makefile > +++ b/drivers/acpi/Makefile > @@ -2,7 +2,6 @@ > # Makefile for the Linux ACPI interpreter > # > > -ccflags-y := -Os > ccflags-$(CONFIG_ACPI_DEBUG) += -DACPI_DEBUG_OUTPUT > > # I checked out Linux 4.9.16, applied your patch on top, and copied the Debian 4.9 Linux kernel configuration, did `make menuconfig`, disabled building debugging symbols, and executed `ARCH=i386 make -j40 deb-pkg`. I installed that package on the Lenovo X60, and the result with tracing enabled has improved. The system suspends without a crash. Unfortunately, instead of resuming when pressing the power button, it starts from scratch. Suspend and resume without tracing enabled works though. I’ll try to collect logs, but I don’t know, if there will be any, if the system just resets. Maybe, this can be reproduced in QEMU? Kind regards, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Dear Josh, On 2017-03-21 21:44, Paul Menzel wrote: > On 2017-03-16 14:56, Josh Poimboeuf wrote: >> Paul Menzel reported a warning: >> >> WARNING: CPU: 0 PID: 774 at >> /build/linux-ROBWaj/linux-4.9.13/kernel/trace/trace_functions_graph.c:233 >> ftrace_return_to_handler+0x1aa/0x1e0 >> Bad frame pointer: expected f6919d98, received f6919db0 >> from func acpi_pm_device_sleep_wake return to c43b6f9d >> >> The warning means that function graph tracing is broken for the >> acpi_pm_device_sleep_wake() function. That's because the acpi >> Makefile >> unconditionally sets the '-Os' gcc flag to optimize for size. That's >> an >> issue because mcount-based function graph tracing is incompatible with >> '-Os' on x86, thanks to the following gcc bug: >> >> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109 >> >> I have another patch pending which will ensure that mcount-based >> function graph tracing is never used with CONFIG_CC_OPTIMIZE_FOR_SIZE >> on >> x86. >> >> But this patch is needed in addition to that one because the ACPI >> Makefile overrides that config option for no apparent reason. It has >> had this flag since the beginning of git history, and there's no >> related >> comment, so I don't know why it's there. As far as I can tell, >> there's >> no reason for it to be there. The appropriate behavior is for it to >> honor CONFIG_CC_OPTIMIZE_FOR_{SIZE,PERFORMANCE} like the rest of the >> kernel. >> >> Reported-by: Paul Menzel <pmenzel@molgen.mpg.de> >> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> >> --- >> drivers/acpi/Makefile | 1 - >> 1 file changed, 1 deletion(-) >> >> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile >> index a391bbc..d94f92f 100644 >> --- a/drivers/acpi/Makefile >> +++ b/drivers/acpi/Makefile >> @@ -2,7 +2,6 @@ >> # Makefile for the Linux ACPI interpreter >> # >> >> -ccflags-y := -Os >> ccflags-$(CONFIG_ACPI_DEBUG) += -DACPI_DEBUG_OUTPUT >> >> # > > I checked out Linux 4.9.16, applied your patch on top, and copied the > Debian 4.9 Linux kernel configuration, did `make menuconfig`, disabled > building debugging symbols, and executed `ARCH=i386 make -j40 > deb-pkg`. > > I installed that package on the Lenovo X60, and the result with > tracing enabled has improved. The system suspends without a crash. > Unfortunately, instead of resuming when pressing the power button, it > starts from scratch. Suspend and resume without tracing enabled works > though. > > I’ll try to collect logs, but I don’t know, if there will be any, if > the system just resets. The system is able to resume with `no_console_suspend` passed to Linux on its command line. ``` $ more /proc/cmdline BOOT_IMAGE=/vmlinuz-4.9.16 root=UUID=0198e82a-32df-4f18-bec0-3e08802b084d ro noisapnp pcie_aspm=force pcie_aspm.policy=powersave nmi_watchdog=0 iomem=relaxed console=t tyS1,115200 console=tty0 no_console_suspend ``` Please tell me, what you need from my side. > Maybe, this can be reproduced in QEMU? Kind regards, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index a391bbc..d94f92f 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -2,7 +2,6 @@ # Makefile for the Linux ACPI interpreter # -ccflags-y := -Os ccflags-$(CONFIG_ACPI_DEBUG) += -DACPI_DEBUG_OUTPUT #
Paul Menzel reported a warning: WARNING: CPU: 0 PID: 774 at /build/linux-ROBWaj/linux-4.9.13/kernel/trace/trace_functions_graph.c:233 ftrace_return_to_handler+0x1aa/0x1e0 Bad frame pointer: expected f6919d98, received f6919db0 from func acpi_pm_device_sleep_wake return to c43b6f9d The warning means that function graph tracing is broken for the acpi_pm_device_sleep_wake() function. That's because the acpi Makefile unconditionally sets the '-Os' gcc flag to optimize for size. That's an issue because mcount-based function graph tracing is incompatible with '-Os' on x86, thanks to the following gcc bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109 I have another patch pending which will ensure that mcount-based function graph tracing is never used with CONFIG_CC_OPTIMIZE_FOR_SIZE on x86. But this patch is needed in addition to that one because the ACPI Makefile overrides that config option for no apparent reason. It has had this flag since the beginning of git history, and there's no related comment, so I don't know why it's there. As far as I can tell, there's no reason for it to be there. The appropriate behavior is for it to honor CONFIG_CC_OPTIMIZE_FOR_{SIZE,PERFORMANCE} like the rest of the kernel. Reported-by: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> --- drivers/acpi/Makefile | 1 - 1 file changed, 1 deletion(-)