Commit-ID: 8eb231261fdd20768db23863d00ef277de4b0543
Gitweb: http://git.kernel.org/tip/8eb231261fdd20768db23863d00ef277de4b0543
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Tue, 7 Jul 2015 14:11:00 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 7 Jul 2015 18:46:47 +0200
tick/broadcast: Prevent hrtimer recursion
The hrtimer based broadcast vehicle can cause a hrtimer recursion
which went unnoticed until we changed the hrtimer expiry code to keep
track of the currently running timer.
local_timer_interrupt()
local_handler()
hrtimer_interrupt()
expire_hrtimers()
broadcast_hrtimer()
send_ipis()
local_handler()
hrtimer_interrupt()
....
Solution is simple: Prevent the local handler call from the broadcast
code when the broadcast 'device' is hrtimer based.
[ Split out from a larger combo patch ]
Tested-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Suzuki Poulose <Suzuki.Poulose@xxxxxxx>
Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@xxxxxxx>
Cc: Catalin Marinas <Catalin.Marinas@xxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Preeti U Murthy <preeti@xxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
---
kernel/time/tick-broadcast.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index d39f32c..a762040 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -265,8 +265,22 @@ static bool tick_do_broadcast(struct cpumask *mask)
* Check, if the current cpu is in the mask
*/
if (cpumask_test_cpu(cpu, mask)) {
+ struct clock_event_device *bc = tick_broadcast_device.evtdev;
+
cpumask_clear_cpu(cpu, mask);
- local = true;
+ /*
+ * We only run the local handler, if the broadcast
+ * device is not hrtimer based. Otherwise we run into
+ * a hrtimer recursion.
+ *
+ * local timer_interrupt()
+ * local_handler()
+ * expire_hrtimers()
+ * bc_handler()
+ * local_handler()
+ * expire_hrtimers()
+ */
+ local = !(bc->features & CLOCK_EVT_FEAT_HRTIMER);
}
if (!cpumask_empty(mask)) {
--
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