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From: David Laight <david.laight.linux@gmail.com>
To: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Nathan Chancellor <nathan@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Alexandre Chartre <alexandre.chartre@oracle.com>
Subject: Re: [PATCH] objtool: Fix stack overflow in validate_branch()
Date: Wed, 3 Dec 2025 11:02:26 +0000	[thread overview]
Message-ID: <20251203110226.4ae00f1f@pumpkin> (raw)
In-Reply-To: <mi4tihk4dbncn7belrhp6ooudhpw4vdggerktu5333w3gqf3uf@vqlhc3y667mg>

On Tue, 2 Dec 2025 15:01:17 -0800
Josh Poimboeuf <jpoimboe@kernel.org> wrote:

...
> +	while (fgets(line, sizeof(line), fp)) {
> +		if (strstr(line, "[stack]")) {
> +			if (sscanf(line, "%lx-%lx", &stack_start, &stack_end) != 2) {
> +				ERROR_GLIBC("sscanf");
> +				ret = -1;
> +				goto done;
> +			}
> +			stack_limit = stack_end - rlim.rlim_cur;
> +			goto done;

That assumes 'stack grows down'.
Someone will copy the code onto a 'backwards stack' system one day.
(I can't remember which ones they are.)

	David

  reply	other threads:[~2025-12-03 11:02 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-02 16:16 [PATCH] objtool: Fix stack overflow in validate_branch() Josh Poimboeuf
2025-12-02 16:20 ` Ingo Molnar
2025-12-02 16:49   ` Josh Poimboeuf
2025-12-02 17:03     ` Ingo Molnar
2025-12-02 17:11       ` Josh Poimboeuf
2025-12-02 19:56         ` Josh Poimboeuf
2025-12-02 20:20           ` Ingo Molnar
2025-12-02 22:05             ` David Laight
2025-12-02 23:01               ` Josh Poimboeuf
2025-12-03 11:02                 ` David Laight [this message]
2025-12-03 16:11                 ` Ingo Molnar
2025-12-03 16:40                 ` [tip: objtool/urgent] objtool: Add more robust signal error handling, detect and warn about stack overflows tip-bot2 for Josh Poimboeuf
2025-12-03 18:48                 ` tip-bot2 for Josh Poimboeuf
2025-12-03  9:25     ` [PATCH] objtool: Fix stack overflow in validate_branch() Ingo Molnar
2025-12-03 18:54       ` Josh Poimboeuf
2025-12-03 18:58         ` Josh Poimboeuf
2025-12-03 19:15           ` Ingo Molnar
2025-12-03 19:37             ` David Laight
2025-12-03 20:30               ` Linus Torvalds
2025-12-03 23:53             ` Josh Poimboeuf
2025-12-03 19:11         ` Ingo Molnar
2025-12-04  2:47           ` Josh Poimboeuf
2025-12-02 16:27 ` [tip: objtool/urgent] " tip-bot2 for Josh Poimboeuf
2025-12-02 16:28 ` [PATCH] " Josh Poimboeuf
2025-12-02 16:41   ` Ingo Molnar
2025-12-02 16:44 ` [tip: objtool/urgent] " tip-bot2 for Josh Poimboeuf

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