Module: xenomai-head
Branch: master
Commit: 7b37dfdaa2dd48bec0886113badb7e5195856277
URL:
http://git.xenomai.org/?p=xenomai-head.git;a=commit;h=7b37dfdaa2dd48bec0886113badb7e5195856277
Author: Jan Kiszka <jan.kis...@siemens.com>
Date: Mon Jul 18 14:07:00 2011 +0200
nucleus: Fix racy Linux task state manipulation
xnshadow_relax can race with do_sigwake_event on a different CPU /wrt
manipulating the Linux task state. Fix this by taking nklock before
calling clear_task_nowakeup.
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
ksrc/nucleus/shadow.c | 7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)
diff --git a/ksrc/nucleus/shadow.c b/ksrc/nucleus/shadow.c
index fc0af8e..a228c91 100644
--- a/ksrc/nucleus/shadow.c
+++ b/ksrc/nucleus/shadow.c
@@ -1137,8 +1137,15 @@ void xnshadow_relax(int notify, int reason)
splmax();
rpi_push(thread->sched, thread);
schedule_linux_call(LO_WAKEUP_REQ, current, 0);
+
+ /*
+ * Task nklock to synchronize the Linux task state manipulation with
+ * do_sigwake_event. nklock will be released by xnpod_suspend_thread.
+ */
+ xnlock_get(&nklock);
clear_task_nowakeup(current);
xnpod_suspend_thread(thread, XNRELAX, XN_INFINITE, XN_RELATIVE, NULL);
+
splnone();
if (XENO_DEBUG(NUCLEUS) && rthal_current_domain != rthal_root_domain)
xnpod_fatal("xnshadow_relax() failed for thread %s[%d]",
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