[PATCH] selftests/mm: Add CONFIG_FTRACE to config

[PATCH] selftests/mm: Add CONFIG_FTRACE to config

[Dev Jain]

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.

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/
Signed-off-by: Dev Jain <dev.jain@arm.com>
---
 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

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

[Aishwarya]

Tested the patch on v6.16-rc1.

After applying the patch, I re-ran the kselftest-mm test suite. The specific test
'merge.handle_uprobe_upon_merged_vma' now passes successfully, and the issue is
no longer observed.

Tested-by: Aishwarya TCV <aishwarya.tcv@arm.com>

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

[Pedro Falcato]

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.

While I did consider this before sending my patch, not every architecture
supports uprobes :/ So this isn't a complete fix.

Also, does every architecture support ftrace? If not (and it does not seem so,
e.g there's an ARM variant that does not), I would guess this config fragment
blows up.

-- 
Pedro

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

[Lorenzo Stoakes]

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.

>
> 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>

> ---
>  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
>

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

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 750 bytes --]

On Wed, Jun 11, 2025 at 05:40:11PM +0530, Dev Jain wrote:

> If CONFIG_UPROBES is not set, a merge subtest fails:

...

> 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.

> +++ 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

If we need UPROBES we should enable UPROBES explicitly, otherwise it
looks like we're just randomly enabling FTRACE even though it's not
used itself.  If it's a dependency for UPROBES and we also enable
UPROBES that's a bit more obvious.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

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

[Dev Jain]

On 11/06/25 6:09 pm, Mark Brown wrote:
> On Wed, Jun 11, 2025 at 05:40:11PM +0530, Dev Jain wrote:
>
>> If CONFIG_UPROBES is not set, a merge subtest fails:
> ...
>
>> 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.
>> +++ 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
> If we need UPROBES we should enable UPROBES explicitly, otherwise it
> looks like we're just randomly enabling FTRACE even though it's not
> used itself.  If it's a dependency for UPROBES and we also enable
> UPROBES that's a bit more obvious.

Fair point actually; I'll send a v2 if no other objections are there.

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

[Dev Jain]

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

[Donet Tom]

On 6/11/25 5:40 PM, 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.
>
> 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/
> Signed-off-by: Dev Jain <dev.jain@arm.com>
> ---
>   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

I have tested this patch, and it is working fine.

ok 7 merge.forked_source_vma
#  RUN           merge.handle_uprobe_upon_merged_vma ...
#            OK  merge.handle_uprobe_upon_merged_vma
ok 8 merge.handle_uprobe_upon_merged_vma
# PASSED: 8 / 8 tests passed.


Tested-by : Donet Tom <donettom@linux.ibm.com>

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

[Dev Jain]

On 11/06/25 6:00 pm, Pedro Falcato wrote:
> 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.
> While I did consider this before sending my patch, not every architecture
> supports uprobes :/ So this isn't a complete fix.
>
> Also, does every architecture support ftrace? If not (and it does not seem so,
> e.g there's an ARM variant that does not), I would guess this config fragment
> blows up.

Sorry forgot to reply.

What do you mean by "config fragment blows up"? I think scripts will just pull
these configs and build the kernel, and if the config is not supported, it will
be thrown out of .config, and after applying your patch, the test will be skipped,
so everyone is happy I guess?

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

[Pedro Falcato]

On Thu, Jun 12, 2025 at 11:58:21AM +0530, Dev Jain wrote:
> 
> On 11/06/25 6:00 pm, Pedro Falcato wrote:
> > 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.
> > While I did consider this before sending my patch, not every architecture
> > supports uprobes :/ So this isn't a complete fix.
> > 
> > Also, does every architecture support ftrace? If not (and it does not seem so,
> > e.g there's an ARM variant that does not), I would guess this config fragment
> > blows up.
> 
> Sorry forgot to reply.
> 
> What do you mean by "config fragment blows up"? I think scripts will just pull
> these configs and build the kernel, and if the config is not supported, it will
> be thrown out of .config, and after applying your patch, the test will be skipped,
> so everyone is happy I guess?

Right, I spoke with Mark Brown off-list and apparently it should be safe to add
unsupported config options there (and I wasn't sure about that, maybe it could
fail, or maybe kbuild would fail, or<...>). So yeah, I'm fully supportive of
a patch adding CONFIG_UPROBES.

- 
Pedro