Re: [PATCH] selftests/mm: Add CONFIG_FTRACE to config

[Dev Jain <dev.jain@arm.com>]

On 11/06/25 6:05 pm, Lorenzo Stoakes wrote:
> Thanks for this!
>
> On Wed, Jun 11, 2025 at 05:40:11PM +0530, Dev Jain wrote:
>> If CONFIG_UPROBES is not set, a merge subtest fails:
>>
>> Failure log:
>>
>>    7151 12:46:54.627936  # # #  RUN           merge.handle_uprobe_upon_merged_vma ...
>>    7152 12:46:54.639014  # # f /sys/bus/event_source/devices/uprobe/type
>>    7153 12:46:54.639306  # # fopen: No such file or directory
>>    7154 12:46:54.650451  # # # merge.c:473:handle_uprobe_upon_merged_vma:Expected read_sysfs("/sys/bus/event_source/devices/uprobe/type", &type) (1) == 0 (0)
>>    7155 12:46:54.650730  # # # handle_uprobe_upon_merged_vma: Test terminated by assertion
>>    7156 12:46:54.661750  # # #          FAIL  merge.handle_uprobe_upon_merged_vma
>>    7157 12:46:54.662030  # # not ok 8 merge.handle_uprobe_upon_merged_vma
>>
>> CONFIG_UPROBES is enabled by CONFIG_UPROBE_EVENTS, which gets enabled by
>> CONFIG_FTRACE. Therefore add this config to selftests/mm/config so that
>> CI systems can include this config in the kernel build.
> OK I see the dependency chain here:
>
> menuconfig FTRACE
>       bool "Tracers"
>       depends on TRACING_SUPPORT
>       default y if DEBUG_KERNEL
>       help
>         Enable the kernel tracing infrastructure.
>
> if FTRACE
>
> ...
>
> endif # FTRACE
>
> ..
>
> config UPROBE_EVENTS
>       bool "Enable uprobes-based dynamic events"
>       depends on ARCH_SUPPORTS_UPROBES
>       depends on MMU
>       depends on PERF_EVENTS
>       select UPROBES
>       select PROBE_EVENTS
>       select DYNAMIC_EVENTS
>       select TRACING
>       default y
>
> ...
>
>
> However we also need PERF_EVENTS w, which is defaulted to y if CONFIG_PROFILING
> is set:
>
> config PERF_EVENTS
>       bool "Kernel performance events and counters"
>       default y if PROFILING
>       depends on HAVE_PERF_EVENTS
>       select IRQ_WORK
>
> ...
>
>
> config PROFILING
>       bool "Profiling support"
>       help
>         Say Y here to enable the extended profiling support mechanisms used
>         by profilers.
>
> So maybe to be totally and completely pedantic we should add CONFIG_PROFILING
> here too.

I don't totally understand this config stuff but I will trust you and update
this in v2 : )

>
>> Fixes: efe99fabeb11b ("selftests/mm: add test about uprobe pte be orphan during vma merge")
>> Reported-by: Aishwarya <aishwarya.tcv@arm.com>
>> Closes: https://lore.kernel.org/all/20250610103729.72440-1-aishwarya.tcv@arm.com/
> This is already (semi-)addressed by
> https://lore.kernel.org/linux-mm/20250610122209.3177587-1-pfalcato@suse.de/,
> perhaps worth mentioning?
>
> Pedro's patch is still important, as for any system that hasn't happened to set
> this up, we get a skip + information rather than a failure.
>
>> Signed-off-by: Dev Jain <dev.jain@arm.com>
> This looks correct, see above for nits etc. but:
>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

Thanks.

>
>> ---
>>   tools/testing/selftests/mm/config | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/tools/testing/selftests/mm/config b/tools/testing/selftests/mm/config
>> index a28baa536332..e600b41030c1 100644
>> --- a/tools/testing/selftests/mm/config
>> +++ b/tools/testing/selftests/mm/config
>> @@ -8,3 +8,4 @@ CONFIG_GUP_TEST=y
>>   CONFIG_TRANSPARENT_HUGEPAGE=y
>>   CONFIG_MEM_SOFT_DIRTY=y
>>   CONFIG_ANON_VMA_NAME=y
>> +CONFIG_FTRACE=y
>> --
>> 2.30.2
>>
IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.