[PATCH v2] ppc: cpufreq: disable preemption while checking CPU throttling state

[Michael Ellerman]

Denis Kirjanov <kda at linux-powerpc.org> writes:

>     [   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 at linux-powerpc.org>
>
> v2:  wrap powernv_cpufreq_throttle_check()
> as suggested by Gautham R Shenoy

That should be below the "---".

When did this break?

cheers