On 7/19/2026 12:47 AM, Ziyang Zhang wrote:
> The comment claimed every Linux ABI keeps its syscall numbers well below the
> minimum, and that the minimum is all N has to satisfy. Neither holds.
> 
> MIPS O32 bases its numbering at 4000, so the default 4096 is its getpriority.
> Raising N does not rescue it either, because O32 answers numbers its table 
> does
> not define with ENOSYS before the filter runs, which leaves no number that is
> both free and reachable on that ABI. arm32 bounds N from above too, with 
> ENOSYS
> or SIGILL past ARM_NR_BASE. Say all of this, so the number can be chosen with
> the target in mind.
> 
> guest_base == 0 is not the only requirement either. Host pointers are written
> back through the caller's out pointers, so the guest must match the host's
> pointer width and endianness. Fold that into the existing warning.
> 
> Also assert the two out pointers that lacked it, and point at Lorelei for
> argument marshalling, callbacks and variadic functions.
> 
> Co-authored-by: Kailiang Xu <[email protected]>
> Co-authored-by: Mingyuan Xia <[email protected]>
> Signed-off-by: Ziyang Zhang <[email protected]>
> ---
>  contrib/plugins/dlcall.c | 32 +++++++++++++++++++++++---------
>  1 file changed, 23 insertions(+), 9 deletions(-)
> 

Reviewed-by: Pierrick Bouvier <[email protected]>

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