From: Paul Mackerras <paulus@samba.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc: Fix possible deadlock on page fault
Date: Thu, 5 Sep 2013 19:53:16 +1000 [thread overview]
Message-ID: <20130905095316.GA18222@iris.ozlabs.ibm.com> (raw)
In-Reply-To: <1378365422-25203-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
On Thu, Sep 05, 2013 at 12:47:02PM +0530, Aneesh Kumar K.V wrote:
> @@ -280,6 +280,13 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
>
> perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
>
> + /*
> + * We want to do this outside mmap_sem, because reading code around nip
> + * can result in fault, which will cause a deadlock when called with
> + * mmap_sem held
> + */
> + store_update = store_updates_sp(regs);
We should only call store_updates_sp() if user_mode(regs); that was
the previous behaviour.
Paul.
next prev parent reply other threads:[~2013-09-05 9:53 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-05 7:17 [PATCH] powerpc: Fix possible deadlock on page fault Aneesh Kumar K.V
2013-09-05 9:53 ` Paul Mackerras [this message]
2013-09-05 11:48 ` Aneesh Kumar K.V
2013-09-05 11:50 ` Benjamin Herrenschmidt
2013-09-05 12:35 ` Aneesh Kumar K.V
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