From 37e2a417a6cb6a981c85dfdcd3245a48f99a4165 Mon Sep 17 00:00:00 2001
From: Guillaume Nault <g.nault@alphalink.fr>
Date: Wed, 24 Jul 2013 20:27:45 +0200
Subject: triton: Fix race upon termination
The triton_terminate() function works by setting the need_close flag
of each triton context, then queues this context for execution by a
triton thread if not already running. But if the context is already
being run by a triton thread, it may not notice that its need_close
flag has been updated (this flag is only checked at the beginning
of ctx_thread()). So if no other event wakes up that context (i.e.
if ctx_thread() isn't run again), it will never terminate.
This patch moves the need_close flag check at the end of ctx_thread()
so that a triton context can take the need_close flag into account
event if it's updated while running.
The context spinlock is also used to protect the need_close flag as
it is concurrently updated by triton_terminate().
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
---
accel-pppd/triton/triton.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/accel-pppd/triton/triton.c b/accel-pppd/triton/triton.c
index 267cc2bc..d4c21e2f 100644
--- a/accel-pppd/triton/triton.c
+++ b/accel-pppd/triton/triton.c
@@ -185,11 +185,6 @@ static void ctx_thread(struct _triton_context_t *ctx)
uint64_t tt;
log_debug2("ctx %p %p: enter\n", ctx, ctx->thread);
- if (ctx->need_close) {
- if (ctx->ud->close)
- ctx->ud->close(ctx->ud);
- ctx->need_close = 0;
- }
while (1) {
spin_lock(&ctx->lock);
@@ -234,6 +229,17 @@ static void ctx_thread(struct _triton_context_t *ctx)
break;
}
+ spin_lock(&ctx->lock);
+ if (ctx->need_close) {
+ spin_unlock(&ctx->lock);
+ if (ctx->ud->close) {
+ ctx->ud->close(ctx->ud);
+ }
+ spin_lock(&ctx->lock);
+ ctx->need_close = 0;
+ }
+ spin_unlock(&ctx->lock);
+
log_debug2("ctx %p %p: exit\n", ctx, ctx->thread);
}
--
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