From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F0DF72EB866 for ; Fri, 19 Dec 2025 07:04:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766127884; cv=none; b=py140Vf8Y8SKZL/mSFK18osn/poYA91liygPvixJ2X96gTHnziwSm9g+wlY2a5T6NUgpY796dE9BZ/ZKCJaG99bXQYb6m9lVczhN4fvLPbjuclWrtrv9WHDtJtZbfU1Z/zE1Luuyi4C7Nxxfj4IJi2fKtBxvjMyvIZDG8sv7/ns= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766127884; c=relaxed/simple; bh=7pM3pg1E+9Zhsdy3FeEbki6cuZHG9Wz4UgMWqEJpnNo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tPg5bdYH6byECcrKxOcgkreIA8xRDJsIjlmdjRwLUoRcadiQVsZ8A/z8IEVWXsv2LeUcX1dmvji8wKAGt3pxfVt+aUaOCmBPh7Z3Cv5KNbPyUZDeTFBfr1XbCwbBtXFMlveu5iDTQyJH+f5STLue/3WZ7T8UPyCwu8QfoQpmKTg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TOr918U1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TOr918U1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7AD3C4CEF1; Fri, 19 Dec 2025 07:04:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1766127883; bh=7pM3pg1E+9Zhsdy3FeEbki6cuZHG9Wz4UgMWqEJpnNo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TOr918U1kBoZTAW5Zj1HzhhsHwDFWVt795xvXCPwfM6E+PyiG9LY60zL1vfEb0RGX BOaVX40lZQaLWgAaghTz47Y8D2PAj338vLnd3yeAWHOH1xeiMIUP+VwqxG8iazyZRz DllbqGBkxwWKORxC/b4IqP0Y1gLEm0VHXomya3cgfHlvpuNMFSMTpj319w01wgL7d9 TZ+J64XgCH7cmGJphFXXy8eAQN/cSbo6xtLpsWrXG+LJM6bJT27gvIBlX8jvjwsfcv jJDcoFzBbJyhf2ayhVy9BIG7iR4VmxYCQXn1zbDN7yxY3Qelg8xMTnKCpHtQsgPeh/ sHhI61OJzC5sg== Date: Fri, 19 Dec 2025 09:04:34 +0200 From: Mike Rapoport To: Thorsten Blum Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Kees Cook , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] fork: Replace simple_strtoul with kstrtoul in coredump_filter_setup Message-ID: References: <20251215142152.4082-2-thorsten.blum@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251215142152.4082-2-thorsten.blum@linux.dev> On Mon, Dec 15, 2025 at 03:21:52PM +0100, Thorsten Blum wrote: > Replace simple_strtoul() with the recommended kstrtoul() for parsing the > 'coredump_filter=' boot parameter. > > Check the return value of kstrtoul() and reject invalid values. This > adds error handling while preserving behavior for existing values, and > removes use of the deprecated simple_strtoul() helper. The current code > silently sets 'default_dump_filter = 0' if parsing fails, instead of > leaving the default value (MMF_DUMP_FILTER_DEFAULT) unchanged. > > Rename the static variable 'default_dump_filter' to 'coredump_filter' > since it does not necessarily contain the default value and the current > name can be misleading. > > Signed-off-by: Thorsten Blum Acked-by: Mike Rapoport (Microsoft) > --- > kernel/fork.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/kernel/fork.c b/kernel/fork.c > index b1f3915d5f8e..f33ee7fe53ad 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -1012,13 +1012,14 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) > > __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); > > -static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; > +static unsigned long coredump_filter = MMF_DUMP_FILTER_DEFAULT; > > static int __init coredump_filter_setup(char *s) > { > - default_dump_filter = > - (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & > - MMF_DUMP_FILTER_MASK; > + if (kstrtoul(s, 0, &coredump_filter)) > + return 0; > + coredump_filter <<= MMF_DUMP_FILTER_SHIFT; > + coredump_filter &= MMF_DUMP_FILTER_MASK; > return 1; > } > > @@ -1104,7 +1105,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, > __mm_flags_overwrite_word(mm, mmf_init_legacy_flags(flags)); > mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK; > } else { > - __mm_flags_overwrite_word(mm, default_dump_filter); > + __mm_flags_overwrite_word(mm, coredump_filter); > mm->def_flags = 0; > } > > -- > Thorsten Blum > GPG: 1D60 735E 8AEF 3BE4 73B6 9D84 7336 78FD 8DFE EAD4 > -- Sincerely yours, Mike.