Commit 54812d33 authored Jun 07, 2017 by Akhil P Oommen

staging: android: sync: fix list corruption in fence struct

Fence lock is not taken in sync_print_fence() while calling
sync_print_pt() which in turn calls fence_is_signaled() to check the
status of each fence before printing. This creates a race condition
that corrupts fence data structure when another thread calls
fence_is_signaled_locked() on the same fence. Since we don't need to
signal the fence while logging, it can be fixed by simply checking fence
flag status directly instead of calling fence_is_signaled_locked().

Change-Id: I1b4732cf3779a5b75a372e11170b438a4deabe67
Signed-off-by: Akhil P Oommen <akhilpo@codeaurora.org>

parent ccde34ff

drivers/staging/android/sync_debug.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -87,7 +87,7 @@ static void sync_print_pt(struct seq_file s, struct sync_pt pt, bool fence)
		int status = 1;
		struct sync_timeline *parent = sync_pt_parent(pt);

		if (fence_is_signaled_locked(&pt->base))
		if (test_bit(FENCE_FLAG_SIGNALED_BIT, &pt->base.flags))
		status = pt->base.status;

		seq_printf(s, " %s%spt %s",