[Buildroot] [PATCH] linux: run depmod only if modules directory exists

[Buildroot] [PATCH] linux: run depmod only if modules directory exists

[Paul Cercueil]

If the modules directory that corresponds to the version of the kernel
being built has been deleted, don't try to run depmod, which will
obviously fail.

This can happen for instance when the modules are stripped from the main
root filesystem, and placed into a separate filesystem image, so that
the root filesystem and the kernel can be updated separately.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 linux/linux.mk | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/linux/linux.mk b/linux/linux.mk
index b90b032bb9..d31933fea1 100644
--- a/linux/linux.mk
+++ b/linux/linux.mk
@@ -490,7 +490,8 @@ endef
 # Run depmod in a target-finalize hook, to encompass modules installed by
 # packages.
 define LINUX_RUN_DEPMOD
-	if grep -q "CONFIG_MODULES=y" $(LINUX_DIR)/.config; then \
+	if test -d $(TARGET_DIR)/lib/modules/$(LINUX_VERSION_PROBED) \
+		&& grep -q "CONFIG_MODULES=y" $(LINUX_DIR)/.config; then \
 		$(HOST_DIR)/sbin/depmod -a -b $(TARGET_DIR) $(LINUX_VERSION_PROBED); \
 	fi
 endef
-- 
2.27.0

[Buildroot] [PATCH] linux: run depmod only if modules directory exists

[Yann E. MORIN]

Paul, All,

On 2020-06-23 13:38 +0200, Paul Cercueil spake thusly:
> If the modules directory that corresponds to the version of the kernel
> being built has been deleted, don't try to run depmod, which will
> obviously fail.
> 
> This can happen for instance when the modules are stripped from the main
> root filesystem, and placed into a separate filesystem image, so that
> the root filesystem and the kernel can be updated separately.

I fail to see how this can happen, sine:

  - LINUX_RUN_DEPMOD is run as a TARGET_FINALIZE_HOOKS

  - TARGET_FINALIZE_HOOKS are run ultra-early in the target-finalize
    step, way before we run post-build scripts.

So, how can you end up with a /lib/modules/VERSIO/ directory missing?

(Note that I find your reason valid, I'm just curious to understand how
this can happen before I apply the patch.)

Regards,
Yann E. MORIN.

> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
>  linux/linux.mk | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/linux/linux.mk b/linux/linux.mk
> index b90b032bb9..d31933fea1 100644
> --- a/linux/linux.mk
> +++ b/linux/linux.mk
> @@ -490,7 +490,8 @@ endef
>  # Run depmod in a target-finalize hook, to encompass modules installed by
>  # packages.
>  define LINUX_RUN_DEPMOD
> -	if grep -q "CONFIG_MODULES=y" $(LINUX_DIR)/.config; then \
> +	if test -d $(TARGET_DIR)/lib/modules/$(LINUX_VERSION_PROBED) \
> +		&& grep -q "CONFIG_MODULES=y" $(LINUX_DIR)/.config; then \
>  		$(HOST_DIR)/sbin/depmod -a -b $(TARGET_DIR) $(LINUX_VERSION_PROBED); \
>  	fi
>  endef
> -- 
> 2.27.0
> 
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 561 099 427 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'

[Buildroot] [PATCH] linux: run depmod only if modules directory exists

[Paul Cercueil]

Hi Yann,

Le mer. 24 juin 2020 ? 22:17, Yann E. MORIN <yann.morin.1998@free.fr> 
a ?crit :
> Paul, All,
> 
> On 2020-06-23 13:38 +0200, Paul Cercueil spake thusly:
>>  If the modules directory that corresponds to the version of the 
>> kernel
>>  being built has been deleted, don't try to run depmod, which will
>>  obviously fail.
>> 
>>  This can happen for instance when the modules are stripped from the 
>> main
>>  root filesystem, and placed into a separate filesystem image, so 
>> that
>>  the root filesystem and the kernel can be updated separately.
> 
> I fail to see how this can happen, sine:
> 
>   - LINUX_RUN_DEPMOD is run as a TARGET_FINALIZE_HOOKS
> 
>   - TARGET_FINALIZE_HOOKS are run ultra-early in the target-finalize
>     step, way before we run post-build scripts.
> 
> So, how can you end up with a /lib/modules/VERSIO/ directory missing?
> 
> (Note that I find your reason valid, I'm just curious to understand 
> how
> this can happen before I apply the patch.)

In the first run, the modules folder is erased after LINUX_RUN_DEPMOD 
is executed, yes. The problem is in successive runs, because then 
LINUX_RUN_DEPMOD is still executed but the modules folder is gone and 
is not re-installed unless the kernel package is rebuilt.

Cheers,
-Paul

> Regards,
> Yann E. MORIN.
> 
>>  Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>>  ---
>>   linux/linux.mk | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>> 
>>  diff --git a/linux/linux.mk b/linux/linux.mk
>>  index b90b032bb9..d31933fea1 100644
>>  --- a/linux/linux.mk
>>  +++ b/linux/linux.mk
>>  @@ -490,7 +490,8 @@ endef
>>   # Run depmod in a target-finalize hook, to encompass modules 
>> installed by
>>   # packages.
>>   define LINUX_RUN_DEPMOD
>>  -	if grep -q "CONFIG_MODULES=y" $(LINUX_DIR)/.config; then \
>>  +	if test -d $(TARGET_DIR)/lib/modules/$(LINUX_VERSION_PROBED) \
>>  +		&& grep -q "CONFIG_MODULES=y" $(LINUX_DIR)/.config; then \
>>   		$(HOST_DIR)/sbin/depmod -a -b $(TARGET_DIR) 
>> $(LINUX_VERSION_PROBED); \
>>   	fi
>>   endef
>>  --
>>  2.27.0
>> 
>>  _______________________________________________
>>  buildroot mailing list
>>  buildroot at busybox.net
>>  http://lists.busybox.net/mailman/listinfo/buildroot
> 
> --
> .-----------------.--------------------.------------------.--------------------.
> |  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' 
> conspiracy: |
> | +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___      
>          |
> | +33 561 099 427 `------------.-------:  X  AGAINST      |  \e/  
> There is no  |
> | http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   
> conspiracy.  |
> '------------------------------^-------^------------------^--------------------'

[Buildroot] [PATCH] linux: run depmod only if modules directory exists

[Yann E. MORIN]

Paul, All,

On 2020-06-23 13:38 +0200, Paul Cercueil spake thusly:
> If the modules directory that corresponds to the version of the kernel
> being built has been deleted, don't try to run depmod, which will
> obviously fail.
> 
> This can happen for instance when the modules are stripped from the main
> root filesystem, and placed into a separate filesystem image, so that
> the root filesystem and the kernel can be updated separately.
> 
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
>  linux/linux.mk | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/linux/linux.mk b/linux/linux.mk
> index b90b032bb9..d31933fea1 100644
> --- a/linux/linux.mk
> +++ b/linux/linux.mk
> @@ -490,7 +490,8 @@ endef
>  # Run depmod in a target-finalize hook, to encompass modules installed by
>  # packages.
>  define LINUX_RUN_DEPMOD
> -	if grep -q "CONFIG_MODULES=y" $(LINUX_DIR)/.config; then \
> +	if test -d $(TARGET_DIR)/lib/modules/$(LINUX_VERSION_PROBED) \

Removing stuff from target and then expecting everything continues to
work as expected is a bit hackish, I believe. But another maintainer
was OK with that patch, so applied to master now, thanks.

Regards,
Yann E. MORIN.

> +		&& grep -q "CONFIG_MODULES=y" $(LINUX_DIR)/.config; then \
>  		$(HOST_DIR)/sbin/depmod -a -b $(TARGET_DIR) $(LINUX_VERSION_PROBED); \
>  	fi
>  endef
> -- 
> 2.27.0
> 
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 561 099 427 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'

[Buildroot] [PATCH] linux: run depmod only if modules directory exists

[Peter Korsgaard]

>>>>> "Yann" == Yann E MORIN <yann.morin.1998@free.fr> writes:

 > Paul, All,
 > On 2020-06-23 13:38 +0200, Paul Cercueil spake thusly:
 >> If the modules directory that corresponds to the version of the kernel
 >> being built has been deleted, don't try to run depmod, which will
 >> obviously fail.
 >> 
 >> This can happen for instance when the modules are stripped from the main
 >> root filesystem, and placed into a separate filesystem image, so that
 >> the root filesystem and the kernel can be updated separately.
 >> 
 >> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
 >> ---
 >> linux/linux.mk | 3 ++-
 >> 1 file changed, 2 insertions(+), 1 deletion(-)
 >> 
 >> diff --git a/linux/linux.mk b/linux/linux.mk
 >> index b90b032bb9..d31933fea1 100644
 >> --- a/linux/linux.mk
 >> +++ b/linux/linux.mk
 >> @@ -490,7 +490,8 @@ endef
 >> # Run depmod in a target-finalize hook, to encompass modules installed by
 >> # packages.
 >> define LINUX_RUN_DEPMOD
 >> -	if grep -q "CONFIG_MODULES=y" $(LINUX_DIR)/.config; then \
 >> +	if test -d $(TARGET_DIR)/lib/modules/$(LINUX_VERSION_PROBED) \

 > Removing stuff from target and then expecting everything continues to
 > work as expected is a bit hackish, I believe. But another maintainer
 > was OK with that patch, so applied to master now, thanks.

Committed to 2020.02.x and 2020.05.x, thanks.

-- 
Bye, Peter Korsgaard