Re: build failure with crosstools gcc 15.1.0

["Arnd Bergmann" <arnd@arndb.de>]

On Thu, Jul 24, 2025, at 12:44, Mark Rutland wrote:
> On Fri, Jul 04, 2025 at 03:25:49PM +0200, Arnd Bergmann wrote:
>> On Mon, Jun 23, 2025, at 21:52, Jeff Johnson wrote:
>> > vmlinux.o: warning: objtool: ncsi_process_next_channel() falls through 
>> > to next function ncsi_channel_monitor.cold()
>> > vmlinux.o: error: objtool [elf.c:1360]: elf_write: elf_update failed: 
>> 
>> Sorry for the late reply, have you figured it out in the meantime?
>> 
>> I couldn't immediately reproduce it, so it may already be fixed
>> in linux-next.
>
> $ git clean -fdx
> $ usekorg 15.1.0 make ARCH=x86_64 CROSS_COMPILE=x86_64-linux- defconfig
> $ usekorg 15.1.0 make ARCH=x86_64 CROSS_COMPILE=x86_64-linux- -j56

This is very close to what I use. I assume you are also on an arm64
host here?

> Doing the same with the 14.2.0 binaries, e.g.
>
> $ git clean -fdx
> $ usekorg 14.2.0 make ARCH=x86_64 CROSS_COMPILE=x86_64-linux- defconfig
> $ usekorg 14.2.0 make ARCH=x86_64 CROSS_COMPILE=x86_64-linux- -j56
>
> ... builds successfully, but there are some objtool warnings:
>
> |   LD      vmlinux.o
> | vmlinux.o: warning: objtool: x86_init_dev_msi_info+0x58: relocation 
> to !ENDBR: irq_chip_retrigger_hierarchy+0x0
> | vmlinux.o: warning: objtool: .export_symbol+0x3e78: data relocation 
> to !ENDBR: irq_chip_retrigger_hierarchy+0x0
> | vmlinux.o: warning: objtool: .export_symbol+0x31140: data relocation 
> to !ENDBR: stpcpy+0x0
> | vmlinux.o: warning: objtool: dmar_msi_controller+0x58: data 
> relocation to !ENDBR: irq_chip_retrigger_hierarchy+0x0
> | vmlinux.o: warning: objtool: intcapxt_controller+0x58: data 
> relocation to !ENDBR: irq_chip_retrigger_hierarchy+0x0
> | vmlinux.o: warning: objtool: hpet_msi_controller+0x58: data 
> relocation to !ENDBR: irq_chip_retrigger_hierarchy+0x0
> | vmlinux.o: warning: objtool: ioapic_ir_chip+0x58: data relocation to 
> !ENDBR: irq_chip_retrigger_hierarchy+0x0
> | vmlinux.o: warning: objtool: ioapic_chip+0x58: data relocation to 
> !ENDBR: irq_chip_retrigger_hierarchy+0x0

My build output is empty with either of those toolchains. However
I've seen a couple of other warnings on randconfig builds recently,
all of these are with gcc-15.1:

drivers/gpu/drm/msm/msm.o: warning: objtool: submit_lock_objects+0x10c: sibling call from callable instruction with modified stack frame
drivers/gpu/drm/msm/msm_gem_submit.o: warning: objtool: submit_lock_objects+0x147: sibling call from callable instruction with modified stack frame
drivers/media/cec/core/cec-adap.o: warning: objtool: cec_receive_notify.isra.0+0x6c5: ignoring unreachables due to jump table quirk
kernel/trace/rv/reactor_panic.o: warning: objtool: rv_panic_reaction(): unexpected end of section .text.unlikely
vmlinux.o: warning: objtool: hdmi_display_enable+0x145: hdmi_pll_compute() missing __noreturn in .c/.h or NORETURN() in noreturns.h

      Arnd