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Date: Wed, 2 Sep 2026 17:51:54 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>, Bill Wendling <morbo@google.com>,
 Justin Stitt <justinstitt@google.com>, linux-kernel@vger.kernel.org,
 llvm@lists.linux.dev
Subject: Re: [PATCH] scripts/checkstack.pl: support llvm-objdump disassembly
 for x86
Message-Id: <20260902175154.14870f981733146727c67c20@linux-foundation.org>
In-Reply-To: <20260902-checkstack_llvm_objdump-v1-1-edb4eca5f163@google.com>
References: <20260902-checkstack_llvm_objdump-v1-1-edb4eca5f163@google.com>
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On Wed, 02 Sep 2026 14:01:53 -0700 Nick Desaulniers <ndesaulniers@google.com> wrote:

> When running `make LLVM=1 checkstack`, OBJDUMP is set to llvm-objdump.
> llvm-objdump outputs disassembly with instruction size suffixes (such as
> subq/addq/subl/addl), tabs/whitespace differences, spaces after commas,
> and trailing comments (e.g. `# imm = 0x...`).
> 
> Because scripts/checkstack.pl used rigid regular expressions specifically
> tuned to GNU objdump format (e.g. requiring exactly four spaces, no
> suffix, and no space after comma), checkstack.pl failed to match any
> stack adjustment instructions and yielded no output when using
> llvm-objdump on x86.
> 
> Update the regular expressions for x86 to match optional suffixes,
> variable whitespace, and trailing comments.

OK, so checkstack is broken with LLVM.

Users of checkstack/LLVM in earlier kernels won't like that, so
should we backport this with cc:stable?