Re: wait skips signals but first one

[Chet Ramey]

On 1/5/24 2:46 PM, Mykyta Dorokhin wrote:

> Bash Version: 5.1
> Patch Level: 16
> Release Status: release
>
> Description:
>
>
> I'm working on a custom project within the Yocto framework. After a recent 
> build system update, the bash
> version updated to 5.1.16. Subsequently, I've noticed peculiar side effects 
> related to using 'wait' and signals.
> Below is a script demonstrating the issue.
>
> The problem lies in the fact that, in the case of waiting on 'wait' in the 
> script, only the first signal
> interrupts 'wait'; subsequent signals of the same type do not interrupt 'wait', 
> and it remains blocked.
>
> I manually switched bash versions and compiled a table (bash version - Yocto 
> version):
>
> 5.0.18 (dunfell): No issues
> 5.1.4 (hardknott): Has issues
> 5.1.8 (honister): Has issues
> 5.1.16 (kirkstone): Has issues
> 5.2.21 (master): Has issues
>
> Meanwhile, in my home desktop distribution, Ubuntu 22.04, I tested the same 
> scenario, and everything works correctly; signals are processed as expected.
>
> My assumption is that the problem may be related to my Yocto build being 
> intended for a 32-bit device, and perhaps the bug only manifests in this case.

The only way I could see a potential problem was if you're using a 32-bit
build on a 64-bit device.


> I consider this a significant issue. Could you confirm whether any testing has 
> been conducted on 32-bit platforms,
> as it seems that everything works correctly on 64-bit desktops?

I don't have any 32-bit platforms available for testing, but I have a hard
time believing that it would make a difference.

Like you, I can't reproduce it on the desktop platforms I have available
right now.

The bash devel git branch has fairly fine granularity. If you can automate
the signal sending somewhat, maybe by having a child process send signals
to $$, you could use your script and `git bisect' to find the commit where
the behavior changed. bash-5.0 was frozen 12/31/2018, and bash-5.1 was
frozen 12/14/2020, so that should get you started with the devel branch
commits you want to inspect.

http://git.savannah.gnu.org/cgit/bash.git/log/?h=devel


--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

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