From: Arnd Bergmann <arnd@arndb.de>
To: cbe-oss-dev@ozlabs.org, michael@ellerman.id.au
Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [Cbe-oss-dev] [PATCH 14/22] spufs: use SPU master control to prevent wild SPU execution
Date: Thu, 1 Mar 2007 14:50:50 +0100 [thread overview]
Message-ID: <200703011450.50935.arnd@arndb.de> (raw)
In-Reply-To: <1172729890.5852.40.camel@concordia.ozlabs.ibm.com>
On Thursday 01 March 2007, Michael Ellerman wrote:
> On Mon, 2006-11-20 at 18:45 +0100, Arnd Bergmann wrote:
> > plain text document attachment (spufs-master-control.diff)
> > When the user changes the runcontrol register, an SPU might be
> > running without a process being attached to it and waiting for
> > events. In order to prevent this, make sure we always disable
> > the priv1 master control when we're not inside of spu_run.
>
> Hi Arnd,
>
> Sorry I didn't comment on this when you sent it, I wasn't paying enough
> attention. This patch confuses me, you say we should make sure we always
> disable the master control when we're not inside spu_run, but I see
> several exit paths where we leave the master run bit enabled - or maybe
> I'm reading it wrong.
I think you're right, there is at least one path that I now saw
getting out of spufs_run_spu incorrectly. In particular, when
spu_reacquire_runnable() fails, we never call the master stop,
which is a bug, but should happen very infrequently in practice.
Do you see another case where we end up with the same problem?
If not, I'll prepare a patch to fix this one case.
Arnd <><
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: cbe-oss-dev@ozlabs.org, michael@ellerman.id.au
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org
Subject: Re: [Cbe-oss-dev] [PATCH 14/22] spufs: use SPU master control to prevent wild SPU execution
Date: Thu, 1 Mar 2007 14:50:50 +0100 [thread overview]
Message-ID: <200703011450.50935.arnd@arndb.de> (raw)
In-Reply-To: <1172729890.5852.40.camel@concordia.ozlabs.ibm.com>
On Thursday 01 March 2007, Michael Ellerman wrote:
> On Mon, 2006-11-20 at 18:45 +0100, Arnd Bergmann wrote:
> > plain text document attachment (spufs-master-control.diff)
> > When the user changes the runcontrol register, an SPU might be
> > running without a process being attached to it and waiting for
> > events. In order to prevent this, make sure we always disable
> > the priv1 master control when we're not inside of spu_run.
>
> Hi Arnd,
>
> Sorry I didn't comment on this when you sent it, I wasn't paying enough
> attention. This patch confuses me, you say we should make sure we always
> disable the master control when we're not inside spu_run, but I see
> several exit paths where we leave the master run bit enabled - or maybe
> I'm reading it wrong.
I think you're right, there is at least one path that I now saw
getting out of spufs_run_spu incorrectly. In particular, when
spu_reacquire_runnable() fails, we never call the master stop,
which is a bug, but should happen very infrequently in practice.
Do you see another case where we end up with the same problem?
If not, I'll prepare a patch to fix this one case.
Arnd <><
next prev parent reply other threads:[~2007-03-01 13:50 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-20 17:44 [PATCH 00/22] Cell patches for 2.6.20 Arnd Bergmann
2006-11-20 17:44 ` Arnd Bergmann
2006-11-20 17:44 ` [PATCH 01/22] powerpc: convert idle_loop to use hard_irq_disable() Arnd Bergmann
2006-11-20 17:44 ` Arnd Bergmann
2006-11-20 21:59 ` Paul Mackerras
2006-11-20 21:59 ` Paul Mackerras
2006-11-21 0:53 ` Benjamin Herrenschmidt
2006-11-21 0:53 ` Benjamin Herrenschmidt
2006-11-21 10:14 ` Arnd Bergmann
2006-11-21 10:14 ` Arnd Bergmann
2006-11-21 16:58 ` Olof Johansson
2006-11-21 16:58 ` Olof Johansson
2006-11-20 17:44 ` [PATCH 02/22] powerpc: change ppc_rtas declaration to weak Arnd Bergmann
2006-11-20 17:44 ` Arnd Bergmann
2006-11-20 17:44 ` [PATCH 03/22] spufs: Change %llx to 0x%llx Arnd Bergmann
2006-11-20 17:44 ` Arnd Bergmann
2006-11-20 17:44 ` [PATCH 04/22] spufs: add /lslr, /dma_info and /proxydma files Arnd Bergmann
2006-11-20 17:44 ` Arnd Bergmann
2006-11-20 17:44 ` [PATCH 05/22] spufs: Remove /spu_tag_mask file Arnd Bergmann
2006-11-20 17:44 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 06/22] spufs: implement /mbox_info, /ibox_info, and /wbox_info Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 07/22] spufs: read from signal files only if data is there Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 08/22] spufs: replace spu.nid with spu.node Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 09/22] spufs: return correct event for data storage interrupt Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 10/22] spufs: fix missing stop-and-signal Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 11/22] spufs: avoid user-triggered oops in ptrace Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 12/22] spufs: always map local store non-guarded Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 13/22] spufs: fix return value of spufs_mfc_write Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 14/22] spufs: use SPU master control to prevent wild SPU execution Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2007-03-01 6:18 ` Michael Ellerman
2007-03-01 6:18 ` Michael Ellerman
2007-03-01 13:50 ` Arnd Bergmann [this message]
2007-03-01 13:50 ` [Cbe-oss-dev] " Arnd Bergmann
2007-03-02 10:13 ` Michael Ellerman
2007-03-02 10:13 ` Michael Ellerman
2007-03-05 1:02 ` Arnd Bergmann
2007-03-07 8:58 ` Michael Ellerman
2007-03-07 8:58 ` Michael Ellerman
2006-11-20 17:45 ` [PATCH 15/22] spufs: Add runcntrl read accessors Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 16/22] spufs: load isolation kernel from spu_run Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 17/22] coredump: Add SPU elf notes to coredump Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-21 5:38 ` Michael Ellerman
2006-11-21 5:38 ` Michael Ellerman
2006-11-20 17:45 ` [PATCH 18/22] cell: add symbol exports for oprofile Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 19/22] cell: PMU register macros Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 20/22] cell: Move PMU-related stuff to include/asm-powerpc/cell-pmu.h Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 21/22] cell: add routines for managing PMU interrupts Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
2006-11-20 17:45 ` [PATCH 22/22] cell: add oprofile support Arnd Bergmann
2006-11-20 17:45 ` Arnd Bergmann
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