Re: [patch 0/4] entry: Rework syscall skip logic

["Michal Suchánek" <msuchanek@suse.de>]

On Sun, Jul 12, 2026 at 11:25:12PM +0200, Thomas Gleixner wrote:
> This are the reworked leftovers of the larger entry logic rework series,
> which can be found here:
> 
>   https://lore.kernel.org/lkml/20260707181957.433213175@kernel.org
> 
> The undisputed part of the series has been merged into:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git core/entry
> 
> After a fruitless discussion about the most resilent approach, I decided to
> give up wasting my time and reworked the series so it caters to the desire
> of powerpc and s390 to be special.
> 
> That results in almost identical behavior except for the case where
> tracing/probe/BPF sets the syscall number to -1 (or any other out of range
> value) and also sets the syscall return value to something different than
> -ENOSYS.
> 
> PowerPC and S390 will overwrite that value with -ENOSYS.
> 
> Loongarch, RISC-V and x86 will not overwrite it because those architectures
> preset the return value to -ENOSYS and skip out of range syscalls
> completely. Loongarch and RISC-V always did the out of range skip. X86
> gained that in the already applied rework, which means that the final patch
> which splits the skip decision from the syscall number does not longer
> change x86 behavior for the above case.
> 
> Documentation is also updated and describes the two implementation variants
> and the subtle difference in the resulting behavior.
> 
> The series applies on top of:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git core/entry
> 
> and is also available from git:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git entry/rework

Hello,

applying this on top of 7.2~rc3 and running tests for the cases that
were reported as problematic I see results as expected.

This version of the patchset works for me.

Tested-by: Michal Suchánek <msuchanek@suse.de>

This is certainly not comprehensive, there are many corner cases not
tested. Some were broken to start with as well.

Thanks

Michal