Commit 79fe9044 authored Oct 17, 2017 by Maheshwar Ajja

msm: vidc: Fix mutex lock deadlock issue



The debugfs method to trigger ssr has already acquired
debugfs srcu lock and is trying to acquire device->lock
in trigger_ssr() function. device->lock was already
acquired by another thread in core_release(). The function
core_release() calling ion_client_destroy() api which is
is trying to acquire the same debugfs srcu lock in function
debugfs_remove_recursive() resulting in deadlock between
trigger_ssr() and core_release() functions. Resolve the 
issue by acquiring core->lock before trigger_ssr() function
to ensure trigger_ssr() and core_release() functions does not
execute at the same time.

CRs-Fixed: 2128555
Change-Id: I35c5c115f0e6281f47a7f108ec75c5870efa743e
Signed-off-by: Maheshwar Ajja <majja@codeaurora.org>

parent 099e9fc7

drivers/media/platform/msm/vidc/msm_vidc_common.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -5302,6 +5302,8 @@ int msm_vidc_trigger_ssr(struct msm_vidc_core *core,
		return -EINVAL;
		}
		hdev = core->device;

		mutex_lock(&core->lock);
		if (core->state == VIDC_CORE_INIT_DONE) {
		/*
		* In current implementation user-initiated SSR triggers
		@@ -5317,7 +5319,11 @@ int msm_vidc_trigger_ssr(struct msm_vidc_core *core,
		__func__);
		core->trigger_ssr = false;
		}
		} else {
		dprintk(VIDC_WARN, "%s: video core %pK not initialized\n",
		__func__, core);
		}
		mutex_unlock(&core->lock);

		return rc;
		}