Yabin Cui edda32dabe coresight: Serialize enabling/disabling a link device. ... When tracing etm data of multiple threads on multiple cpus through perf interface, some link devices are shared between paths of different cpus. It creates race conditions when different cpus wants to enable/disable the same link device at the same time. Example 1: Two cpus want to enable different ports of a coresight funnel, thus calling the funnel enable operation at the same time. But the funnel enable operation isn't reentrantable. Example 2: For an enabled coresight dynamic replicator with refcnt=1, one cpu wants to disable it, while another cpu wants to enable it. Ideally we still have an enabled replicator with refcnt=1 at the end. But in reality the result is uncertain. Since coresight devices claim themselves when enabled for self-hosted usage, the race conditions above usually make the link devices not usable after many cycles. To fix the race conditions, this patch uses spinlocks to serialize enabling/disabling link devices. Fixes: a06ae8609b ("coresight: add CoreSight core layer framework") Signed-off-by: Yabin Cui <yabinc@google.com> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: stable <stable@vger.kernel.org> # 5.3 Link: https://lore.kernel.org/r/20191104181251.26732-14-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2019-11-04 21:57:57 +01:00
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coresight	coresight: Serialize enabling/disabling a link device.	2019-11-04 21:57:57 +01:00
intel_th	Char/Misc driver patches for 5.4-rc1	2019-09-18 11:14:31 -07:00
stm	LED updates for 5.4-rc1	2019-09-17 18:40:42 -07:00
Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00