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| author | Li Zhong <zhong@linux.vnet.ibm.com> | 2012-11-23 00:05:03 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2012-11-23 00:05:03 +0100 |
| commit | a093b93ee0e08cd73a07848752bc09ecea68cb13 (patch) | |
| tree | 7a59d44658150cf43de771556fc0320505cc82b2 /drivers/cpuidle | |
| parent | bf4d1b5ddb78f86078ac6ae0415802d5f0c68f92 (diff) | |
| download | linux-a093b93ee0e08cd73a07848752bc09ecea68cb13.tar.gz linux-a093b93ee0e08cd73a07848752bc09ecea68cb13.tar.bz2 linux-a093b93ee0e08cd73a07848752bc09ecea68cb13.zip | |
cpuidle: fix a suspicious RCU usage in menu governor
I saw this suspicious RCU usage on the next tree of 11/15
[ 67.123404] ===============================
[ 67.123413] [ INFO: suspicious RCU usage. ]
[ 67.123423] 3.7.0-rc5-next-20121115-dirty #1 Not tainted
[ 67.123434] -------------------------------
[ 67.123444] include/trace/events/timer.h:186 suspicious rcu_dereference_check() usage!
[ 67.123458]
[ 67.123458] other info that might help us debug this:
[ 67.123458]
[ 67.123474]
[ 67.123474] RCU used illegally from idle CPU!
[ 67.123474] rcu_scheduler_active = 1, debug_locks = 0
[ 67.123493] RCU used illegally from extended quiescent state!
[ 67.123507] 1 lock held by swapper/1/0:
[ 67.123516] #0: (&cpu_base->lock){-.-...}, at: [<c0000000000979b0>] .__hrtimer_start_range_ns+0x28c/0x524
[ 67.123555]
[ 67.123555] stack backtrace:
[ 67.123566] Call Trace:
[ 67.123576] [c0000001e2ccb920] [c00000000001275c] .show_stack+0x78/0x184 (unreliable)
[ 67.123599] [c0000001e2ccb9d0] [c0000000000c15a0] .lockdep_rcu_suspicious+0x120/0x148
[ 67.123619] [c0000001e2ccba70] [c00000000009601c] .enqueue_hrtimer+0x1c0/0x1c8
[ 67.123639] [c0000001e2ccbb00] [c000000000097aa0] .__hrtimer_start_range_ns+0x37c/0x524
[ 67.123660] [c0000001e2ccbc20] [c0000000005c9698] .menu_select+0x508/0x5bc
[ 67.123678] [c0000001e2ccbd20] [c0000000005c740c] .cpuidle_idle_call+0xa8/0x6e4
[ 67.123699] [c0000001e2ccbdd0] [c0000000000459a0] .pSeries_idle+0x10/0x34
[ 67.123717] [c0000001e2ccbe40] [c000000000014dc8] .cpu_idle+0x130/0x280
[ 67.123738] [c0000001e2ccbee0] [c0000000006ffa8c] .start_secondary+0x378/0x384
[ 67.123758] [c0000001e2ccbf90] [c00000000000936c] .start_secondary_prolog+0x10/0x14
hrtimer_start was added in 198fd638 and ae515197. The patch below tries
to use RCU_NONIDLE around it to avoid the above report.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle')
| -rw-r--r-- | drivers/cpuidle/governors/menu.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 2efee27714a0..bd40b943b6db 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -407,8 +407,9 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) perfect_us = perfect_cstate_ms * 1000; if (repeat && (4 * timer_us < data->expected_us)) { - hrtimer_start(hrtmr, ns_to_ktime(1000 * timer_us), - HRTIMER_MODE_REL_PINNED); + RCU_NONIDLE(hrtimer_start(hrtmr, + ns_to_ktime(1000 * timer_us), + HRTIMER_MODE_REL_PINNED)); /* In repeat case, menu hrtimer is started */ per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_REPEAT; } else if (perfect_us < data->expected_us) { @@ -418,8 +419,9 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) * In that case, it makes sense to re-enter * into a deeper C-state after some time. */ - hrtimer_start(hrtmr, ns_to_ktime(1000 * timer_us), - HRTIMER_MODE_REL_PINNED); + RCU_NONIDLE(hrtimer_start(hrtmr, + ns_to_ktime(1000 * timer_us), + HRTIMER_MODE_REL_PINNED)); /* In general case, menu hrtimer is started */ per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_GENERAL; } |