From: Petr Mladek <pmladek@suse.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Yue Haibing <yuehaibing@huawei.com>,
sergey.senozhatsky@gmail.com, andriy.shevchenko@linux.intel.com,
geert+renesas@glider.be, me@tobin.cc,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH -next] lib/vsprintf: Make function pointer_string static
Date: Mon, 29 Apr 2019 16:30:37 +0200 [thread overview]
Message-ID: <20190429143037.3qu5fzdo6g26rsmf@pathway.suse.cz> (raw)
In-Reply-To: <20190429091320.019e726b@gandalf.local.home>
On Mon 2019-04-29 09:13:20, Steven Rostedt wrote:
> On Mon, 29 Apr 2019 13:08:01 +0200
> Petr Mladek <pmladek@suse.com> wrote:
>
> > > Looks like commit "vsprintf: Do not check address of well-known
> > > strings" removed the: "static noinline_for_stack"
> > >
> > > Does pointer_string() need that still?
> >
> > Heh, it was removed by mistake and well hidden in the diff.
> >
> > I have pushed Yue's fix into printk.git, branch
> > for-5.2-vsprintf-hardening
> >
> > Thanks for the patch.
>
> But doesn't it still need the "noinline_for_stack", that doesn't look
> like it changed.
Good question. I have just double checked it. And pointer_string() with
"noinline_for_stack" does not make any difference in the stack
usage here.
I actually played with this before:
"noinline_for_stack" is a black magic added by
the commit cf3b429b03e827c7180 ("vsprintf.c: use noinline_for_stack").
It is evidently useful in some cases. But I somehow doubt
that it really makes things better when used everywhere.
Therefore I have got a bit relaxed and omitted it in most
newly added functions that did not affect the results.
They are the same before and after the patchset:
pmladek@pathway:/prace/kernel/linux-printk> objdump -d lib/vsprintf.o | perl scripts/checkstack.pl
0x00000e12 symbol_string [vsprintf.o]: 248
0x00000e6d symbol_string [vsprintf.o]: 248
0x000012fb ip6_addr_string_sa [vsprintf.o]: 112
0x00001415 ip6_addr_string_sa [vsprintf.o]: 112
0x000028c6 resource_string.isra.9 [vsprintf.o]: 104
0x00002964 resource_string.isra.9 [vsprintf.o]: 104
Would you like to fix this clearly, for example, rebase and
put both "static noinline_for_stack" back or add yet
another commit or?
IMHO, it is not too important. Anyway, I am open for any
advice. I do not want to create more mess.
Best Regards,
Petr
next prev parent reply other threads:[~2019-04-29 14:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-26 16:46 [PATCH -next] lib/vsprintf: Make function pointer_string static Yue Haibing
2019-04-26 17:02 ` Steven Rostedt
2019-04-29 11:08 ` Petr Mladek
2019-04-29 13:13 ` Steven Rostedt
2019-04-29 14:30 ` Petr Mladek [this message]
2019-04-29 14:39 ` Steven Rostedt
2019-04-29 16:42 ` Joe Perches
2019-04-30 8:42 ` Petr Mladek
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