From: Eric Dumazet <edumazet@google.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Eric Dumazet <eric.dumazet@gmail.com>,
Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH] x86/traps: do not hash pointers in handle_stack_overflow()
Date: Fri, 7 Feb 2020 07:18:18 -0800 [thread overview]
Message-ID: <CANn89i+mo08vK3ejvmn7DxvHEkAox4Xpm9Dm5hGc=9-+Xwxi4g@mail.gmail.com> (raw)
In-Reply-To: <87tv42xxr5.fsf@nanos.tec.linutronix.de>
On Fri, Feb 7, 2020 at 6:44 AM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> Eric Dumazet <edumazet@google.com> writes:
>
> > Mangling stack pointers in handle_stack_overflow() is moot,
> > as registers (including RSP/RBP) are clear anyway.
> >
> > BUG: stack guard page was hit at 0000000063381e80 (stack is
> > 000000008edc5696..0000000012256c50)
>
> To illustrate your argument above it would be useful to provide the post
> patch output as well.
Unfortunately this KASAN report has no repro yet. I have no idea what
triggered the fault ;)
>
> > kernel stack overflow (double-fault): 0000 [#1] PREEMPT SMP KASAN
> > ...
> > RSP: 0018:ffffc90002c1ffc0 EFLAGS: 00010802
> > RAX: 1ffff11004a0094c RBX: ffff888025004180 RCX: c9d82d1007bb146c
> > RDX: dffffc0000000000 RSI: ffff888025004a40 RDI: ffff888025004180
> > RBP: ffffc90002c201c0 R08: dffffc0000000000 R09: fffffbfff1405915
> > R10: fffffbfff1405915 R11: 0000000000000000 R12: ffff888025004a60
> > R13: ffff888025004a10 R14: c9d82d1007bb146c R15: ffff888025004180
> > ...
> >
> > Signed-off-by: Eric Dumazet <edumazet@google.com>
> > Cc: Andy Lutomirski <luto@kernel.org>
> > ---
> > arch/x86/kernel/traps.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> > index 6ef00eb6fbb925e86109f86845e2b3ccef4023ec..44873df292bd3f9f77bb721c53cb8a1c40994cca 100644
> > --- a/arch/x86/kernel/traps.c
> > +++ b/arch/x86/kernel/traps.c
> > @@ -296,7 +296,7 @@ __visible void __noreturn handle_stack_overflow(const char *message,
> > struct pt_regs *regs,
> > unsigned long fault_address)
> > {
> > - printk(KERN_EMERG "BUG: stack guard page was hit at %p (stack is %p..%p)\n",
> > + printk(KERN_EMERG "BUG: stack guard page was hit at %px (stack
> > is %px..%px)\n",
>
> While touching this, can you please switch it to pr_emerg() ?
>
Sure I will, thanks.
prev parent reply other threads:[~2020-02-07 15:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-07 4:38 [PATCH] x86/traps: do not hash pointers in handle_stack_overflow() Eric Dumazet
2020-02-07 14:44 ` Thomas Gleixner
2020-02-07 15:18 ` Eric Dumazet [this message]
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