Re: Build failures: unresolved symbol vfs_getattr

From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Veronika Kabatova <vkabatov@redhat.com>,
	Andrii Nakryiko <andriin@fb.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	bpf <bpf@vger.kernel.org>, "Frank Ch. Eigler" <fche@redhat.com>,
	Mark Wielaard <mjw@redhat.com>
Subject: Re: Build failures: unresolved symbol vfs_getattr
Date: Fri, 23 Oct 2020 11:22:05 -0700	[thread overview]
Message-ID: <CAEf4BzbM=FhKUUjaM9msL1k=t_CSrhoWUNYcubzToZvbAJCJ-A@mail.gmail.com> (raw)
In-Reply-To: <20201023065832.GA2435078@krava>

On Thu, Oct 22, 2020 at 11:58 PM Jiri Olsa <jolsa@redhat.com> wrote:
>
> On Fri, Oct 23, 2020 at 07:36:57AM +0200, Jiri Olsa wrote:
> > On Thu, Oct 22, 2020 at 01:00:19PM -0700, Andrii Nakryiko wrote:
> >
> > SNIP
> >
> > > >
> > > > hi,
> > > > FYI there's still no solution yet, so far the progress is:
> > > >
> > > > the proposed workaround was to use the negation -> we don't have
> > > > DW_AT_declaration tag, so let's find out instead which DW_TAG_subprogram
> > > > tags have attached code and skip them if they don't have any:
> > > >   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97060#c10
> > > >
> > > > the attached patch is doing that, but the resulting BTF is missing
> > > > several functions due to another bug in dwarf:
> > > >   https://bugzilla.redhat.com/show_bug.cgi?id=1890107
> > >
> > > It seems fine if there are only few functions (especially if those are
> > > unlikely to be traced). Do you have an estimate of how many functions
> > > have this second DWARF bug?
> >
> > it wasn't that many, I'll recheck
>
> 127 functions missing if the workaround is applied, list attached
>

some of those seem pretty useful... I guess the quick workaround in
pahole would be to just remember function names that were emitted
already. The problem with that is that we can pick a version without
parameter names, which is not the end of the world, but certainly
annoying.

But otherwise, I don't really have a good feeling what's the perfect
solution here...

> jirka
>
>
> ---
> 'acpi_ev_default_region_setup'
> 'acpi_ev_pci_bar_region_setup'
> 'acpi_ex_pci_bar_space_handler'
> 'acpi_ex_stop_trace_opcode'
> 'acpi_os_notify_command_complete'
> 'arch_cpu_idle_exit'
> 'arch_unregister_hw_breakpoint'
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> 'cap_task_setnice'
> 'cryptd_aead_queued'
> 'devm_regmap_field_bulk_free'
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> 'ext4_ext_release'
> 'fs_param_is_path'
> 'HUF_isError'
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> '__ia32_compat_sys_getsockopt'
> '__ia32_compat_sys_io_pgetevents_time32'
> '__ia32_compat_sys_preadv64'
> '__ia32_compat_sys_process_vm_readv'
> '__ia32_compat_sys_process_vm_writev'
> '__ia32_compat_sys_pwritev64'
> '__ia32_compat_sys_s390_ipc'
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> '__ia32_sys_fadvise64'
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> '__ia32_sys_geteuid16'
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> '__ia32_sys_getuid16'
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> '__ia32_sys_munlockall'
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> '__ia32_sys_old_shmctl'
> '__ia32_sys_pciconfig_iobase'
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> '__ia32_sys_pciconfig_write'
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> '_raw_write_unlock_irqrestore'
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> 'sock_no_shutdown'
> 'synchronize_rcu_tasks'
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> 'text_poke_kgdb'
> 'tty_driver_kref_put'
> 'watchdog_nmi_start'
> '__x64_sys_fadvise64'
> '__x64_sys_getegid16'
> '__x64_sys_geteuid16'
> '__x64_sys_getgid16'
> '__x64_sys_getuid16'
> '__x64_sys_inotify_init'
> '__x64_sys_io_pgetevents_time32'
> '__x64_sys_ipc'
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> '__x64_sys_old_shmctl'
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> '__x64_sys_s390_pci_mmio_read'
> '__x64_sys_s390_pci_mmio_write'
> '__x64_sys_sgetmask'
> '__x64_sys_spu_create'
> '__x64_sys_spu_run'
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> '__x64_sys_uselib'
> '__x64_sys_vm86'
> '__x64_sys_vm86old'
> 'xen_has_pv_nic_devices'
>