From: Denis Kirjanov <kda@linux-powerpc.org>
To: linuxppc-dev@lists.ozlabs.org
Cc: ego@linux.vnet.ibm.com, Denis Kirjanov <kda@linux-powerpc.org>
Subject: [PATCH v2] ppc: cpufreq: disable preemption while checking CPU throttling state
Date: Fri, 4 Nov 2016 07:08:38 -0400 [thread overview]
Message-ID: <1478257718-14923-1-git-send-email-kda@linux-powerpc.org> (raw)
[ 67.700897] BUG: using smp_processor_id() in preemptible [00000000] code: cat/7343
[ 67.700988] caller is .powernv_cpufreq_throttle_check+0x2c/0x710
[ 67.700998] CPU: 13 PID: 7343 Comm: cat Not tainted 4.8.0-rc5-dirty #1
[ 67.701038] Call Trace:
[ 67.701066] [c0000007d25b75b0] [c000000000971378] .dump_stack+0xe4/0x150 (unreliable)
[ 67.701153] [c0000007d25b7640] [c0000000005162e4] .check_preemption_disabled+0x134/0x150
[ 67.701238] [c0000007d25b76e0] [c0000000007b63ac] .powernv_cpufreq_throttle_check+0x2c/0x710
[ 67.701322] [c0000007d25b7790] [c0000000007b6d18] .powernv_cpufreq_target_index+0x288/0x360
[ 67.701407] [c0000007d25b7870] [c0000000007acee4] .__cpufreq_driver_target+0x394/0x8c0
[ 67.701491] [c0000007d25b7920] [c0000000007b22ac] .cpufreq_set+0x7c/0xd0
[ 67.701565] [c0000007d25b79b0] [c0000000007adf50] .store_scaling_setspeed+0x80/0xc0
[ 67.701650] [c0000007d25b7a40] [c0000000007ae270] .store+0xa0/0x100
[ 67.701723] [c0000007d25b7ae0] [c0000000003566e8] .sysfs_kf_write+0x88/0xb0
[ 67.701796] [c0000007d25b7b70] [c0000000003553b8] .kernfs_fop_write+0x178/0x260
[ 67.701881] [c0000007d25b7c10] [c0000000002ac3cc] .__vfs_write+0x3c/0x1c0
[ 67.701954] [c0000007d25b7cf0] [c0000000002ad584] .vfs_write+0xc4/0x230
[ 67.702027] [c0000007d25b7d90] [c0000000002aeef8] .SyS_write+0x58/0x100
[ 67.702101] [c0000007d25b7e30] [c00000000000bfec] system_call+0x38/0xfc
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
v2: wrap powernv_cpufreq_throttle_check()
as suggested by Gautham R Shenoy
---
drivers/cpufreq/powernv-cpufreq.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index d3ffde8..112e0e2 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -647,8 +647,15 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
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());
--
1.8.3.1
next reply other threads:[~2016-11-04 11:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-04 11:08 Denis Kirjanov [this message]
2016-11-07 2:31 ` [PATCH v2] ppc: cpufreq: disable preemption while checking CPU throttling state Gautham R Shenoy
2016-11-07 5:15 ` Denis Kirjanov
2016-11-07 7:36 ` Michael Ellerman
2016-11-07 8:02 ` Denis Kirjanov
2016-11-08 0:21 ` Michael Ellerman
2016-11-08 3:17 ` Gautham R Shenoy
2016-11-08 8:27 ` Michael Ellerman
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