On Thu, Jan 28, 2021 at 01:38:25PM +0000, Chris Clayton wrote:

Thanks, Thomas.

On 28/01/2021 11:24, Thomas Backlund wrote:

...

Den 28.1.2021 kl. 12:05, skrev Chris Clayton:

...

On 28/01/2021 09:34, Greg Kroah-Hartman wrote:

...

On Thu, Jan 28, 2021 at 09:17:10AM +0000, Chris Clayton wrote:

...

Hi,

Building 5.10.11 fails on my (x86-64) laptop thusly:

..

AS arch/x86/entry/thunk_64.o CC arch/x86/entry/vsyscall/vsyscall_64.o AS arch/x86/realmode/rm/header.o CC arch/x86/mm/pat/set_memory.o CC arch/x86/events/amd/core.o CC arch/x86/kernel/fpu/init.o CC arch/x86/entry/vdso/vma.o CC kernel/sched/core.o arch/x86/entry/thunk_64.o: warning: objtool: missing symbol for insn at offset 0x3e

AS arch/x86/realmode/rm/trampoline_64.o make[2]: *** [scripts/Makefile.build:360: arch/x86/entry/thunk_64.o] Error 255 make[2]: *** Deleting file 'arch/x86/entry/thunk_64.o' make[2]: *** Waiting for unfinished jobs....

..

Compiler is latest snapshot of gcc-10.

Happy to test the fix but please cc me as I'm not subscribed

Can you do 'git bisect' to track down the offending commit?

Sure, but I'll hold that request for a while. I updated to binutils-2.36 on Monday and I'm pretty sure that is a feature of this build fail. I've reverted binutils to 2.35.1, and the build succeeds. Updated to 2.36 again and, surprise, surprise, the kernel build fails again.

I've had a glance at the binutils ML and there are all sorts of issues being reported, but it's beyond my knowledge to assess if this build error is related to any of them.

I'll stick with binutils-2.35.1 for the time being.

...

And what exact gcc version are you using?

It's built from the 10-20210123 snapshot tarball.

I can report this to the binutils folks, but might it be better if the objtool maintainer looks at it first? The binutils change might just have opened the gate to a bug in objtool.

...

thanks,

greg k-h

AFAIK you need this in stable trees:

From 1d489151e9f9d1647110277ff77282fe4d96d09b Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf jpoimboe@redhat.com Date: Thu, 14 Jan 2021 16:14:01 -0600 Subject: [PATCH] objtool: Don't fail on missing symbol table

That may be the caae, but it doesn't fix the build failure I've reported in this thread. However, as suggested by Tor, https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/patch/?id=5e6dca... does fix it.

That hasn't made Linus' tree yet and I don't see a pull request, but it is in linux-next so I guess it could make it in -rc6.

Ok, thanks, so this is not a new regression for 5.10.y.

greg k-h

On Thu, Jan 28, 2021 at 01:38:25PM +0000, Chris Clayton wrote:

Thanks, Thomas.

On 28/01/2021 11:24, Thomas Backlund wrote:

...

Den 28.1.2021 kl. 12:05, skrev Chris Clayton:

...

On 28/01/2021 09:34, Greg Kroah-Hartman wrote:

...

On Thu, Jan 28, 2021 at 09:17:10AM +0000, Chris Clayton wrote:

...

Hi,

Building 5.10.11 fails on my (x86-64) laptop thusly:

..

AS arch/x86/entry/thunk_64.o CC arch/x86/entry/vsyscall/vsyscall_64.o AS arch/x86/realmode/rm/header.o CC arch/x86/mm/pat/set_memory.o CC arch/x86/events/amd/core.o CC arch/x86/kernel/fpu/init.o CC arch/x86/entry/vdso/vma.o CC kernel/sched/core.o arch/x86/entry/thunk_64.o: warning: objtool: missing symbol for insn at offset 0x3e

AS arch/x86/realmode/rm/trampoline_64.o make[2]: *** [scripts/Makefile.build:360: arch/x86/entry/thunk_64.o] Error 255 make[2]: *** Deleting file 'arch/x86/entry/thunk_64.o' make[2]: *** Waiting for unfinished jobs....

..

Compiler is latest snapshot of gcc-10.

Happy to test the fix but please cc me as I'm not subscribed

Can you do 'git bisect' to track down the offending commit?

Sure, but I'll hold that request for a while. I updated to binutils-2.36 on Monday and I'm pretty sure that is a feature of this build fail. I've reverted binutils to 2.35.1, and the build succeeds. Updated to 2.36 again and, surprise, surprise, the kernel build fails again.

I've had a glance at the binutils ML and there are all sorts of issues being reported, but it's beyond my knowledge to assess if this build error is related to any of them.

I'll stick with binutils-2.35.1 for the time being.

...

And what exact gcc version are you using?

It's built from the 10-20210123 snapshot tarball.

I can report this to the binutils folks, but might it be better if the objtool maintainer looks at it first? The binutils change might just have opened the gate to a bug in objtool.

...

thanks,

greg k-h

AFAIK you need this in stable trees:

From 1d489151e9f9d1647110277ff77282fe4d96d09b Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf jpoimboe@redhat.com Date: Thu, 14 Jan 2021 16:14:01 -0600 Subject: [PATCH] objtool: Don't fail on missing symbol table

That may be the caae, but it doesn't fix the build failure I've reported in this thread. However, as suggested by Tor, https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/patch/?id=5e6dca... does fix it.

That hasn't made Linus' tree yet and I don't see a pull request, but it is in linux-next so I guess it could make it in -rc6.

I mistakenly thought this was already in Linus' tree and submitted this patch to stable a few days ago.

I talked to Boris (-tip maintainer), he's going to submit a pull request to Linus this weekend.

On 28/01/2021 15:52, Josh Poimboeuf wrote:

On Thu, Jan 28, 2021 at 11:24:47AM +0000, Thomas Backlund wrote:

...

Den 28.1.2021 kl. 12:05, skrev Chris Clayton:

...

On 28/01/2021 09:34, Greg Kroah-Hartman wrote:

...

On Thu, Jan 28, 2021 at 09:17:10AM +0000, Chris Clayton wrote:

...

Hi,

Building 5.10.11 fails on my (x86-64) laptop thusly:

..

AS arch/x86/entry/thunk_64.o CC arch/x86/entry/vsyscall/vsyscall_64.o AS arch/x86/realmode/rm/header.o CC arch/x86/mm/pat/set_memory.o CC arch/x86/events/amd/core.o CC arch/x86/kernel/fpu/init.o CC arch/x86/entry/vdso/vma.o CC kernel/sched/core.o arch/x86/entry/thunk_64.o: warning: objtool: missing symbol for insn at offset 0x3e

AS arch/x86/realmode/rm/trampoline_64.o make[2]: *** [scripts/Makefile.build:360: arch/x86/entry/thunk_64.o] Error 255 make[2]: *** Deleting file 'arch/x86/entry/thunk_64.o' make[2]: *** Waiting for unfinished jobs....

..

Compiler is latest snapshot of gcc-10.

Happy to test the fix but please cc me as I'm not subscribed

Can you do 'git bisect' to track down the offending commit?

Sure, but I'll hold that request for a while. I updated to binutils-2.36 on Monday and I'm pretty sure that is a feature of this build fail. I've reverted binutils to 2.35.1, and the build succeeds. Updated to 2.36 again and, surprise, surprise, the kernel build fails again.

I've had a glance at the binutils ML and there are all sorts of issues being reported, but it's beyond my knowledge to assess if this build error is related to any of them.

I'll stick with binutils-2.35.1 for the time being.

...

And what exact gcc version are you using?

It's built from the 10-20210123 snapshot tarball.

I can report this to the binutils folks, but might it be better if the objtool maintainer looks at it first? The binutils change might just have opened the gate to a bug in objtool.

...

thanks,

greg k-h

AFAIK you need this in stable trees:

From 1d489151e9f9d1647110277ff77282fe4d96d09b Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf jpoimboe@redhat.com Date: Thu, 14 Jan 2021 16:14:01 -0600 Subject: [PATCH] objtool: Don't fail on missing symbol table

Actually I think you need:

5e6dca82bcaa ("x86/entry: Emit a symbol for register restoring thunk")

I submitted a patch to stable list a few days ago.

Yes, that's what I concluded, Josh. 5.10.11 builds with that patch added but it's not in Linus's tree yet, so, as I understand it, is not yet a candidate from stable.

(Though it's possible you need both commits, I'm not sure if binutils 2.36 has the symbol stripping stuff)