From: <gregkh@linuxfoundation.org>
To: kda@linux-powerpc.org, ego@linux.vnet.ibm.com,
gregkh@linuxfoundation.org, rafael.j.wysocki@intel.com
Cc: <stable@vger.kernel.org>, <stable-commits@vger.kernel.org>
Subject: Patch "cpufreq: powernv: Disable preemption while checking CPU throttling state" has been added to the 4.4-stable tree
Date: Tue, 17 Jan 2017 17:11:21 +0100 [thread overview]
Message-ID: <14846694817571@kroah.com> (raw)
This is a note to let you know that I've just added the patch titled
cpufreq: powernv: Disable preemption while checking CPU throttling state
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cpufreq-powernv-disable-preemption-while-checking-cpu-throttling-state.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From 8a10c06a20ec8097a68fd7a4a1c0e285095b4d2f Mon Sep 17 00:00:00 2001
From: Denis Kirjanov <kda@linux-powerpc.org>
Date: Tue, 8 Nov 2016 05:39:28 -0500
Subject: cpufreq: powernv: Disable preemption while checking CPU throttling state
From: Denis Kirjanov <kda@linux-powerpc.org>
commit 8a10c06a20ec8097a68fd7a4a1c0e285095b4d2f upstream.
With preemption turned on we can read incorrect throttling state
while being switched to CPU on a different chip.
BUG: using smp_processor_id() in preemptible [00000000] code: cat/7343
caller is .powernv_cpufreq_throttle_check+0x2c/0x710
CPU: 13 PID: 7343 Comm: cat Not tainted 4.8.0-rc5-dirty #1
Call Trace:
[c0000007d25b75b0] [c000000000971378] .dump_stack+0xe4/0x150 (unreliable)
[c0000007d25b7640] [c0000000005162e4] .check_preemption_disabled+0x134/0x150
[c0000007d25b76e0] [c0000000007b63ac] .powernv_cpufreq_throttle_check+0x2c/0x710
[c0000007d25b7790] [c0000000007b6d18] .powernv_cpufreq_target_index+0x288/0x360
[c0000007d25b7870] [c0000000007acee4] .__cpufreq_driver_target+0x394/0x8c0
[c0000007d25b7920] [c0000000007b22ac] .cpufreq_set+0x7c/0xd0
[c0000007d25b79b0] [c0000000007adf50] .store_scaling_setspeed+0x80/0xc0
[c0000007d25b7a40] [c0000000007ae270] .store+0xa0/0x100
[c0000007d25b7ae0] [c0000000003566e8] .sysfs_kf_write+0x88/0xb0
[c0000007d25b7b70] [c0000000003553b8] .kernfs_fop_write+0x178/0x260
[c0000007d25b7c10] [c0000000002ac3cc] .__vfs_write+0x3c/0x1c0
[c0000007d25b7cf0] [c0000000002ad584] .vfs_write+0xc4/0x230
[c0000007d25b7d90] [c0000000002aeef8] .SyS_write+0x58/0x100
[c0000007d25b7e30] [c00000000000bfec] system_call+0x38/0xfc
Fixes: 09a972d16209 (cpufreq: powernv: Report cpu frequency throttling)
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/cpufreq/powernv-cpufreq.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -373,8 +373,14 @@ static int powernv_cpufreq_target_index(
if (unlikely(rebooting) && new_index != get_nominal_index())
return 0;
- if (!throttled)
+ if (!throttled) {
+ /* we don't want to be preempted while
+ * checking if the CPU frequency has been throttled
+ */
+ preempt_disable();
powernv_cpufreq_throttle_check(NULL);
+ preempt_enable();
+ }
freq_data.pstate_id = powernv_freqs[new_index].driver_data;
Patches currently in stable-queue which might be from kda@linux-powerpc.org are
queue-4.4/cpufreq-powernv-disable-preemption-while-checking-cpu-throttling-state.patch
reply other threads:[~2017-01-17 16:13 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=14846694817571@kroah.com \
--to=gregkh@linuxfoundation.org \
--cc=ego@linux.vnet.ibm.com \
--cc=kda@linux-powerpc.org \
--cc=rafael.j.wysocki@intel.com \
--cc=stable-commits@vger.kernel.org \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.