From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Ravi Bangoria <ravi.bangoria@linux.ibm.com>, mikey@neuling.org
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
"Naveen N . Rao" <naveen.n.rao@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org, paulus@samba.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] powerpc/watchpoint: Disable watchpoint hit by larx/stcx instructions
Date: Thu, 19 Sep 2019 20:25:55 +1000 (AEST) [thread overview]
Message-ID: <46YtKb2HHTz9sPM@ozlabs.org> (raw)
In-Reply-To: <20190910131513.30499-1-ravi.bangoria@linux.ibm.com>
On Tue, 2019-09-10 at 13:15:13 UTC, Ravi Bangoria wrote:
> If watchpoint exception is generated by larx/stcx instructions, the
> reservation created by larx gets lost while handling exception, and
> thus stcx instruction always fails. Generally these instructions are
> used in a while(1) loop, for example spinlocks. And because stcx
> never succeeds, it loops forever and ultimately hangs the system.
>
> Note that ptrace anyway works in one-shot mode and thus for ptrace
> we don't change the behaviour. It's up to ptrace user to take care
> of this.
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/bc01bdf6c5df5023272a7399962cf64f8fedc93e
cheers
WARNING: multiple messages have this Message-ID (diff)
From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Ravi Bangoria <ravi.bangoria@linux.ibm.com>, mikey@neuling.org
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
linux-kernel@vger.kernel.org, paulus@samba.org,
"Naveen N . Rao" <naveen.n.rao@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] powerpc/watchpoint: Disable watchpoint hit by larx/stcx instructions
Date: Thu, 19 Sep 2019 20:25:55 +1000 (AEST) [thread overview]
Message-ID: <46YtKb2HHTz9sPM@ozlabs.org> (raw)
In-Reply-To: <20190910131513.30499-1-ravi.bangoria@linux.ibm.com>
On Tue, 2019-09-10 at 13:15:13 UTC, Ravi Bangoria wrote:
> If watchpoint exception is generated by larx/stcx instructions, the
> reservation created by larx gets lost while handling exception, and
> thus stcx instruction always fails. Generally these instructions are
> used in a while(1) loop, for example spinlocks. And because stcx
> never succeeds, it loops forever and ultimately hangs the system.
>
> Note that ptrace anyway works in one-shot mode and thus for ptrace
> we don't change the behaviour. It's up to ptrace user to take care
> of this.
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/bc01bdf6c5df5023272a7399962cf64f8fedc93e
cheers
next prev parent reply other threads:[~2019-09-19 10:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-10 13:15 [PATCH v2] powerpc/watchpoint: Disable watchpoint hit by larx/stcx instructions Ravi Bangoria
2019-09-10 13:15 ` Ravi Bangoria
2019-09-19 10:25 ` Michael Ellerman [this message]
2019-09-19 10:25 ` Michael Ellerman
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