cpufreq: powernv: Disable preemption while checking CPU throttling state
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>
projects / firefly-linux-kernel-4.4.55.git / commit