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 4.9-stable tree
Date: Tue, 17 Jan 2017 17:12:28 +0100 [thread overview]
Message-ID: <14846695484433@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 4.9-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-4.9 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
@@ -647,8 +647,14 @@ 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();
+ }
cur_msec = jiffies_to_msecs(get_jiffies_64());
Patches currently in stable-queue which might be from kda@linux-powerpc.org are
queue-4.9/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=14846695484433@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).