Messages in this thread Patch in this message | | | From | "Travis, Mike" <> | Subject | Re: [PATCH] x86/platform/uv: Dont use smp_processor_id while preemptable | Date | Sat, 21 May 2022 18:50:34 +0000 |
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Thanks, I'll do that.
________________________________________ From: Hans de Goede <hdegoede@redhat.com> Sent: Saturday, May 21, 2022 6:57 AM To: Travis, Mike; Borislav Petkov; Dave Hansen; Ingo Molnar; Thomas Gleixner; Wahl, Steve; x86@kernel.org Cc: Sivanich, Dimitri; Andy Shevchenko; Darren Hart; H. Peter Anvin; Anderson, Russ; linux-kernel@vger.kernel.org; platform-driver-x86@vger.kernel.org Subject: Re: [PATCH] x86/platform/uv: Dont use smp_processor_id while preemptable
Hi Mike,
On 5/20/22 22:37, Mike Travis wrote: > To avoid a "BUG: using smp_processor_id() in preemptible" debug > warning message, disable preemption around use of the processor id. > > Signed-off-by: Mike Travis <mike.travis@hpe.com> > Reviewed-by: Steve Wahl <steve.wahl@hpe.com> > Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
A git blame shows that this code has been around for quite a while; so presumably this should be backported to some of the stable kernel series ?
Maybe add an appropriate Cc: stable tag with the range of kernels this should be added to and/or add a Fixes: tag?
Regards,
Hans
> --- > arch/x86/platform/uv/uv_time.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/platform/uv/uv_time.c b/arch/x86/platform/uv/uv_time.c > index 54663f3e00cb..094190814a28 100644 > --- a/arch/x86/platform/uv/uv_time.c > +++ b/arch/x86/platform/uv/uv_time.c > @@ -275,14 +275,17 @@ static int uv_rtc_unset_timer(int cpu, int force) > */ > static u64 uv_read_rtc(struct clocksource *cs) > { > - unsigned long offset; > + unsigned long offset, time; > + unsigned int cpu = get_cpu(); > > if (uv_get_min_hub_revision_id() == 1) > offset = 0; > else > - offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE; > + offset = (uv_cpu_blade_processor_id(cpu) * L1_CACHE_BYTES) % PAGE_SIZE; > > - return (u64)uv_read_local_mmr(UVH_RTC | offset); > + time = (u64)uv_read_local_mmr(UVH_RTC | offset); > + put_cpu(); > + return time; > } > > /*
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