From 5ac84ab421465f8f15ac9350f9f33a4416b4b3b7 Mon Sep 17 00:00:00 2001 From: Alexander Potapenko Date: Tue, 9 Sep 2025 12:09:02 +0200 Subject: prog: pkg/compiler: docs: introduce the `no_squash` attribute The `no_squash` per-syscall attribute prevents the fuzzer from generating squashed arguments to a particular syscall. This is particularly helpful for pseudo-syscalls with elaborate arguments that are hard to reason about when they are squashed - e.g. for syz_kvm_add_vcpu() that takes a SYZOS program as an input. I've considered an alternative solution that prohibits ANY for all pseudo-syscalls. But there is a bunch of existing programs (both the tests and the repros) for syscalls like syz_mount_image() for which the benefit of not passing ANY is not immediately obvious. I therefore decided to go with an explicit attribute that can later be enforced for every pseudo-syscall at compile time. --- sys/test/test.txt | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'sys') diff --git a/sys/test/test.txt b/sys/test/test.txt index 71ec2a011..54cf96f9b 100644 --- a/sys/test/test.txt +++ b/sys/test/test.txt @@ -799,6 +799,15 @@ hint_ints { } # Mutation tests. +no_squash_struct { + f0 int32 + f1 int32 + f2 int32 + f3 int32 + f4 array[int8] +} [packed] + +mutate_no_squash(a ptr[in, no_squash_struct]) (no_squash) mutate0() mutate1() -- cgit mrf-deployment