Subject: Re: linux-next: build failure after merge of the perf tree

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Tue, 28 Mar 2023 16:47:23 -0300

Em Tue, Mar 28, 2023 at 12:33:32PM +1100, Stephen Rothwell escreveu:
> Hi Arnaldo,
> 
> Just a few datapoints:
> 
> My build machine (Debian Testing PowerpcLE, not quite the latest
> kernel):
 
> On Thu, 23 Mar 2023 10:27:36 -0300 Arnaldo Carvalho de Melo <[email-masked]> wrote:
> >  Which improves a bit the situation.
> > 
> > We could check if bpftool is available and if not, suggest installing
> > it.
> 
> $ ls -l /usr/sbin/bpftool
> -rwxr-xr-x 1 root root 790504 Mar  6 02:33 /usr/sbin/bpftool
> 
> > If it is available, we could check if /sys/kernel/bpf/ is available, if
> > not suggest using a kernel with CONFIG_DEBUG_INFO_BTF=y, as most distros
> > have by now.

The config files you used don't match the running kernels
 
> $ uname -a
> Linux zz1 6.0.0-5-powerpc64le #1 SMP Debian 6.0.10-2 (2022-12-01) ppc64le GNU/Linux
> $ ls -l /sys/kernel/bpf/
> ls: cannot access '/sys/kernel/bpf/': No such file or directory
> $ grep CONFIG_DEBUG_INFO_BTF /boot/config-6.0.0-5-powerpc64le
> # CONFIG_DEBUG_INFO_BTF is not set
> 
> And in the latest powerpc64le kernel:
> 
> $ grep CONFIG_DEBUG_INFO_BTF /boot/config-6.1.0-5-powerpc64le
> # CONFIG_DEBUG_INFO_BTF is not set
> 
> Debian Testing arm64, not quite the latest kernel:
> 
> $ uname -a
> Linux oak 6.1.0-5-arm64 #1 SMP Debian 6.1.12-1 (2023-02-15) aarch64 GNU/Linux
> $ ls -l /sys/kernel/bpf/
> ls: cannot access '/sys/kernel/bpf/': No such file or directory
> $ grep CONFIG_DEBUG_INFO_BTF /boot/config-6.1.0-5-arm64
> CONFIG_DEBUG_INFO_BTF=y
> CONFIG_DEBUG_INFO_BTF_MODULES=y

The running kernel is 6.1.12-1, the .config is 6.1.0-5

> Debian Testing amd64, the latest kernel:
> 
> $ uname -a
> Linux pine 6.1.0-6-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.15-1 (2023-03-05) x86_64 GNU/Linux
> $ ls -l /sys/kernel/bpf/
> ls: cannot access '/sys/kernel/bpf/': No such file or directory
> $ grep CONFIG_DEBUG_INFO_BTF /boot/config-6.1.0-6-amd64
> CONFIG_DEBUG_INFO_BTF=y
> CONFIG_DEBUG_INFO_BTF_MODULES=y

Ditto, 6.1.15-1 != 6.1.0-6

> 
> Debian Stable amd64, the latest kernel:
> 
> $ uname -a
> Linux gimli 5.10.0-21-cloud-amd64 #1 SMP Debian 5.10.162-1 (2023-01-21) x86_64 GNU/Linux
> $ ls -l /sys/kernel/bpf/
> ls: cannot access '/sys/kernel/bpf/': No such file or directory
> $ grep CONFIG_DEBUG_INFO_BTF /boot/config-5.10.0-21-cloud-amd64
> CONFIG_DEBUG_INFO_BTF=y

Ditto, 5.10.162-1  != 5.10.0-21-cloud

Here:

[acme@quaco pahole]$ grep CONFIG_DEBUG_INFO_BTF /boot/config-`uname -r`
CONFIG_DEBUG_INFO_BTF=y
CONFIG_DEBUG_INFO_BTF_MODULES=y
[acme@quaco pahole]$ uname -r
6.1.18-100.fc36.x86_64
[acme@quaco pahole]$

[acme@quaco pahole]$ ls -la /sys/kernel/btf/vmlinux
-r--r--r--. 1 root root 5499812 Mar 20 17:45 /sys/kernel/btf/vmlinux
[acme@quaco pahole]$ ls -la /sys/kernel/btf/nfsv4
-r--r--r--. 1 root root 319948 Mar 28 16:46 /sys/kernel/btf/nfsv4
[acme@quaco pahole]$ lsmod | grep -w nfsv4
nfsv4                1085440  1
dns_resolver           16384  1 nfsv4
nfs                   532480  2 nfsv4
sunrpc                704512  26 nfsd,rpcrdma,nfsv4,auth_rpcgss,lockd,rpcsec_gss_krb5,nfs_acl,nfs
[acme@quaco pahole]$ ls -la /sys/kernel/btf/nfsd
-r--r--r--. 1 root root 596066 Mar 28 16:46 /sys/kernel/btf/nfsd
[acme@quaco pahole]$ ls -la /sys/kernel/btf/lockd
-r--r--r--. 1 root root 180234 Mar 28 16:46 /sys/kernel/btf/lockd
[acme@quaco pahole]$
 
> -- 
> Cheers,
> Stephen Rothwell