Re: [PATCH] linux-custom: Add lock to dependency installation

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2018-03-05 08:16, Alexander Smirnov wrote:
> 
> 
> On 02/23/2018 12:25 AM, Jan Kiszka wrote:
>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>
>> The build script of linux-custom requires the same lock protection as
>> build.sh of the dpkg builder class. Otherwise, we see the infamous build
>> failures again due to contention on the dpkg database lock.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>   meta/recipes-kernel/linux/files/build-kernel.sh | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/meta/recipes-kernel/linux/files/build-kernel.sh
>> b/meta/recipes-kernel/linux/files/build-kernel.sh
>> index 94897ec..42c8ff6 100644
>> --- a/meta/recipes-kernel/linux/files/build-kernel.sh
>> +++ b/meta/recipes-kernel/linux/files/build-kernel.sh
>> @@ -13,8 +13,10 @@ REPACK_DIR="$1/../repack"
>>   REPACK_LINUX_IMAGE_DIR="${REPACK_DIR}/linux-image"
>>   REPACK_LINUX_HEADERS_DIR="${REPACK_DIR}/linux-headers"
>>   -apt-get install -y -o Debug::pkgProblemResolver=yes
>> --no-install-recommends \
>> -    ${KBUILD_DEPENDS}
>> +# Lock-protected because apt and dpkg do not wait in case of contention
>> +flock /dpkg.lock \
>> +    apt-get install -y -o Debug::pkgProblemResolver=yes \
>> +        --no-install-recommends ${KBUILD_DEPENDS}
> 
> The same stuff as in "meta/recipes-devtools/buildchroot/files/build.sh",
> but different style. Can we keep things similar as much as possible?
> 
> Why not
> 
> (
>    ...
> ) 42>/dpkg.lock
> 
> ?

This is

if (x)
	y;

vs.

if (x) {
	y;
	z;
}

See also the man page of flock.

Jan

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