Re: [34-longterm 228/247] arch/x86/oprofile/op_model_amd.c: Performinitialisation on a single CPU

From: Robert Richter
Date: Mon Jun 27 2011 - 09:52:52 EST


On 24.06.11 09:02:39, Paul Gortmaker wrote:
> On 11-06-24 05:23 AM, Robert Richter wrote:
> > On 23.06.11 13:34:56, Paul Gortmaker wrote:
> >> From: Robert Richter <robert.richter@xxxxxxx>
> >>
> >> -------------------
> >> This is a commit scheduled for the next v2.6.34 longterm release.
> >> If you see a problem with using this for longterm, please comment.
> >> -------------------
> >>
> >> commit c7c25802b39c443b3745cfa973dc49a97a3491f8 upstream.
> >>
> >> Disable preemption in init_ibs(). The function only checks the
> >> ibs capabilities and sets up pci devices (if necessary). It runs
> >> only on one cpu but operates with the local APIC and some MSRs,
> >> thus it is better to disable preemption.
> >>
> >> [ 7.034377] BUG: using smp_processor_id() in preemptible [00000000] code: modprobe/483
> >> [ 7.034385] caller is setup_APIC_eilvt+0x155/0x180
> >> [ 7.034389] Pid: 483, comm: modprobe Not tainted 2.6.37-rc1-20101110+ #1
> >> [ 7.034392] Call Trace:
> >> [ 7.034400] [<ffffffff812a2b72>] debug_smp_processor_id+0xd2/0xf0
> >> [ 7.034404] [<ffffffff8101e985>] setup_APIC_eilvt+0x155/0x180
> >> [ ... ]
> >>
> >> Addresses https://bugzilla.kernel.org/show_bug.cgi?id=22812
> >>
> >> Reported-by: <atswartz@xxxxxxxxx>
> >> Signed-off-by: Robert Richter <robert.richter@xxxxxxx>
> >> Cc: oprofile-list@xxxxxxxxxxxxxxxxxxxxx <oprofile-list@xxxxxxxxxxxxxxxxxxxxx>
> >> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> >> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> >> Cc: Rafael J. Wysocki <rjw@xxxxxxx>
> >> Cc: Dan Carpenter <error27@xxxxxxxxx>
> >> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> >> LKML-Reference: <20110103111514.GM4739@xxxxxxxxxxxx>
> >> [ small cleanups ]
> >> Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> >> Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
> >> ---
> >> arch/x86/oprofile/op_model_amd.c | 24 ++++++++++++++++--------
> >> 1 files changed, 16 insertions(+), 8 deletions(-)
> >
> > This patch introduces a sleeping-while-atomic bug. There is another
> > upstream fix on top, see:
> >
> > commit 3d2606f42984613d324ad3047cf503bcddc3880a
> > Author: Robert Richter <robert.richter@xxxxxxx>
> > Date: Fri May 20 09:46:54 2011 +0200
> >
> > oprofile, x86: Enable preemption during pci device setup in IBS init
> >
> > This fix should be applied too (or instead).
>
> Thanks Robert. I guess I'll end up dropping c7c25802b39c
> then. I just did a quick test and it appears the 2.6.34
> code base is too old for me to be able to apply 3d2606f4298
> in anything close to resembling its original form.

This would be ok. Current upstream code is a reimplementation very
different from .34.

Thanks,

-Robert

--
Advanced Micro Devices, Inc.
Operating System Research Center

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/