From: Heiko Carstens <hca@linux.ibm.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "Doug Anderson" <dianders@chromium.org>,
"Randy Dunlap" <rdunlap@infradead.org>,
linux-kernel@vger.kernel.org, "Andrew Chant" <achant@google.com>,
"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Brian Gerst" <brgerst@gmail.com>,
"Christian Brauner" <brauner@kernel.org>,
"Francesco Valla" <francesco@valla.it>,
"Guo Weikang" <guoweikang.kernel@gmail.com>,
"Huacai Chen" <chenhuacai@kernel.org>,
"Jan Hendrik Farr" <kernel@jfarr.cc>,
"Jeff Xu" <jeffxu@chromium.org>, "Kees Cook" <kees@kernel.org>,
"Masahiro Yamada" <masahiroy@kernel.org>,
"Michal Koutný" <mkoutny@suse.com>,
"Miguel Ojeda" <ojeda@kernel.org>,
"Mike Rapoport (Microsoft)" <rppt@kernel.org>,
"Nathan Chancellor" <nathan@kernel.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Shakeel Butt" <shakeel.butt@linux.dev>,
"Tejun Heo" <tj@kernel.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Thomas Weißschuh" <thomas.weissschuh@linutronix.de>,
"Uladzislau Rezki (Sony)" <urezki@gmail.com>,
"Sven Schnelle" <svens@linux.ibm.com>,
linux-s390 <linux-s390@vger.kernel.org>
Subject: Re: [PATCH] init/main.c: Wrap long kernel cmdline when printing to logs
Date: Tue, 21 Oct 2025 15:16:33 +0200 [thread overview]
Message-ID: <20251021131633.26700Dd6-hca@linux.ibm.com> (raw)
In-Reply-To: <CAMuHMdWGb0jVt9ziBtWdHWC9omPAFMHVPBHDpv0F1XzvR0THpg@mail.gmail.com>
On Tue, Oct 21, 2025 at 09:05:48AM +0200, Geert Uytterhoeven wrote:
> On Mon, 20 Oct 2025 at 18:04, Doug Anderson <dianders@chromium.org> wrote:
> > On Mon, Oct 20, 2025 at 8:42 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > > On Mon, 20 Oct 2025 at 17:33, Doug Anderson <dianders@chromium.org> wrote:
> > > > Printing the command line to the kernel log buffer is one of the very
> > > > rare cases where:
> > > > * There's a legitimate reason to print a (potentially) very long
> > > > string to the kernel buffer.
> > >
> > > arch/s390/Kconfig:
> > >
> > > config COMMAND_LINE_SIZE
> > > int "Maximum size of kernel command line"
> > > default 4096
> > > range 896 1048576
> > >
> > > Yummy...
> >
> > Wow, what are they expecting to stuff in there? An encoded initramfs
> > or something? I kinda feel like the 1MB number isn't something anyone
> > expects but is a number picked to effectively be "unlimited".
>
> Dunno, commit 622021cd6c560ce7 ("s390: make command line configurable")
> lacks the "why" part.
That was just a follow-on patch of commit 5ecb2da660ab ("s390: support command
lines longer than 896 bytes") which solved the real problem with a too short
maximum command line size back then. In order to never have to deal with this
sort of problem again it was made configurable.
But I doubt that anybody will change the default ever.
next prev parent reply other threads:[~2025-10-21 13:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-19 17:06 [PATCH] init/main.c: Wrap long kernel cmdline when printing to logs Douglas Anderson
2025-10-19 22:22 ` Randy Dunlap
2025-10-20 15:33 ` Doug Anderson
2025-10-20 15:40 ` Geert Uytterhoeven
2025-10-20 15:57 ` Doug Anderson
2025-10-21 7:05 ` Geert Uytterhoeven
2025-10-21 13:16 ` Heiko Carstens [this message]
2025-10-21 16:07 ` Doug Anderson
2025-10-20 17:18 ` Randy Dunlap
2025-10-20 18:51 ` Andrew Morton
2025-10-20 20:00 ` Doug Anderson
2025-10-21 20:55 ` Andrew Morton
2025-10-21 22:57 ` Doug Anderson
2025-10-21 23:06 ` Andrew Morton
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