Re: [PATCH] cpufreq: powernv: Fix crash in gpstate_timer_handler

[Viresh Kumar <viresh.kumar@linaro.org>]

On 04-08-16, 20:59, Akshay Adiga wrote:
> 'commit 09ca4c9b5958 ("cpufreq: powernv: Replacing pstate_id with
> frequency table index")' changes calc_global_pstate() to use
> cpufreq_table index instead of pstate_id.
> 
> But in gpstate_timer_handler() pstate_id was being passed instead
> of cpufreq_table index, which caused the index_to_pstate() to access
> out of bound indices, leading to this crash.
> 
> Adding sanity check for index and pstate, to ensure only valid pstate
> and index values are returned.
> 
> Call Trace:
> [c00000078d66b130] [c00000000011d224] __free_irq+0x234/0x360
> (unreliable)
> [c00000078d66b1c0] [c00000000011d44c] free_irq+0x6c/0xa0
> [c00000078d66b1f0] [c00000000006c4f8] opal_event_shutdown+0x88/0xd0
> [c00000078d66b230] [c000000000067a4c] opal_shutdown+0x1c/0x90
> [c00000078d66b260] [c000000000063a00] pnv_shutdown+0x20/0x40
> [c00000078d66b280] [c000000000021538] machine_restart+0x38/0x90
> [c0000000078d66b310] [c000000000965ea0] panic+0x284/0x300
> [c00000078d66b3a0] [c00000000001f508] die+0x388/0x450
> [c00000078d66b430] [c000000000045a50] bad_page_fault+0xd0/0x140
> [c00000078d66b4a0] [c000000000008964] handle_page_fault+0x2c/0x30
>    interrupt: 300 at gpstate_timer_handler+0x150/0x260
>     LR = gpstate_timer_handler+0x130/0x260
> [c00000078d66b7f0] [c000000000132b58] call_timer_fn+0x58/0x1c0
> [c00000078d66b880] [c000000000132e20] expire_timers+0x130/0x1d0
> [c00000078d66b8f0] [c000000000133068] run_timer_softirq+0x1a8/0x230
> [c00000078d66b980] [c0000000000b535c] __do_softirq+0x18c/0x400
> [c00000078d66ba70] [c0000000000b5828] irq_exit+0xc8/0x100
> [c00000078d66ba90] [c00000000001e214] timer_interrupt+0xa4/0xe0
> [c00000078d66bac0] [c0000000000027d0] decrementer_common+0x150/0x180
>    interrupt: 901 at arch_local_irq_restore+0x74/0x90
>   0] [c000000000106b34] call_cpuidle+0x44/0x90
> [c00000078d66be50] [c00000000010708c] cpu_startup_entry+0x38c/0x460
> [c00000078d66bf20] [c00000000003d930] start_secondary+0x330/0x380
> [c00000078d66bf90] [c000000000008e6c] start_secondary_prolog+0x10/0x14
> 
> Fixes: 08d27eb ("cpufreq: powernv: Replacing pstate_id with
> frequency table index")
> Reported-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
> Signed-off-by: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
> ---
>  drivers/cpufreq/powernv-cpufreq.c | 21 ++++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh