[Xenomai-git] Jan Kiszka : nucleus: Fix endless loop of DEBUG_SYNCH_RELAX
Module: xenomai-head
Branch: master
Commit: 834766db37076e444f7fc1acd8bcffd9975c710c
URL:
http://git.xenomai.org/?p=xenomai-head.git;a=commit;h=834766db37076e444f7fc1acd8bcffd9975c710c
Author: Jan Kiszka
Date: Wed Nov 11 10:35:27 2009 +0100
nucleus: Fix endless loop of DEBUG_SYNCH_RELAX
When a thread is about to block on a mutex resource that is currently
held by a relaxed thread, it will receive SIGXCPU if the relaxed owner
debugging feature is enable. But after the signal is delivered and
handled, the sleeper will restart the mutex service and then receive the
same signal over and over again.
Fix this fatal loop by temporarily disabling the warning for the sleeper
after the first delivery, but also rearming it for the next run right
after that. This will still cause re-deliveries for the same blocking
call if the sleeper may fall out due to a different signal delivery. But
endless loops will be avoided and the solution is kept simple.
Signed-off-by: Jan Kiszka
---
include/nucleus/thread.h |1 +
ksrc/nucleus/synch.c | 11 ---
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/include/nucleus/thread.h b/include/nucleus/thread.h
index 389a12b..1124eb4 100644
--- a/include/nucleus/thread.h
+++ b/include/nucleus/thread.h
@@ -62,6 +62,7 @@
#define XNFPU 0x0010 /**< Thread uses FPU */
#define XNSHADOW 0x0020 /**< Shadow thread */
#define XNROOT0x0040 /**< Root thread (that is, Linux/IDLE) */
+#define XNSWREP 0x0080 /**< Mode switch already reported */
/*! @} */ /* Ends doxygen comment group: nucleus_state_flags */
diff --git a/ksrc/nucleus/synch.c b/ksrc/nucleus/synch.c
index 816c7ab..1a9bbb4 100644
--- a/ksrc/nucleus/synch.c
+++ b/ksrc/nucleus/synch.c
@@ -987,9 +987,12 @@ EXPORT_SYMBOL_GPL(xnsynch_release_all_ownerships);
*/
void xnsynch_detect_relaxed_owner(struct xnsynch *synch, struct xnthread
*sleeper)
{
- if (xnthread_test_state(sleeper, XNTRAPSW) &&
- xnthread_test_state(synch->owner, XNRELAX))
+ if (xnthread_test_state(sleeper, XNTRAPSW|XNSWREP) == XNTRAPSW &&
+ xnthread_test_state(synch->owner, XNRELAX)) {
+ xnthread_set_state(sleeper, XNSWREP);
xnshadow_send_sig(sleeper, SIGXCPU, 0, 1);
+ } else
+ xnthread_clear_state(sleeper, XNSWREP);
}
/*
@@ -1010,8 +1013,10 @@ void xnsynch_detect_claimed_relax(struct xnthread *owner)
for (ht = getheadpq(&synch->pendq); ht != NULL;
ht = nextpq(&synch->pendq, ht)) {
sleeper = link2thread(ht, plink);
- if (xnthread_test_state(sleeper, XNRELAX))
+ if (xnthread_test_state(sleeper, XNRELAX)) {
+ xnthread_set_state(sleeper, XNSWREP);
xnshadow_send_sig(sleeper, SIGXCPU, 0, 1);
+ }
}
}
}
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[Xenomai-git] Jan Kiszka : nucleus: Fix endless loop of DEBUG_SYNCH_RELAX
Module: xenomai-jki
Branch: for-upstream
Commit: 834766db37076e444f7fc1acd8bcffd9975c710c
URL:
http://git.xenomai.org/?p=xenomai-jki.git;a=commit;h=834766db37076e444f7fc1acd8bcffd9975c710c
Author: Jan Kiszka
Date: Wed Nov 11 10:35:27 2009 +0100
nucleus: Fix endless loop of DEBUG_SYNCH_RELAX
When a thread is about to block on a mutex resource that is currently
held by a relaxed thread, it will receive SIGXCPU if the relaxed owner
debugging feature is enable. But after the signal is delivered and
handled, the sleeper will restart the mutex service and then receive the
same signal over and over again.
Fix this fatal loop by temporarily disabling the warning for the sleeper
after the first delivery, but also rearming it for the next run right
after that. This will still cause re-deliveries for the same blocking
call if the sleeper may fall out due to a different signal delivery. But
endless loops will be avoided and the solution is kept simple.
Signed-off-by: Jan Kiszka
---
include/nucleus/thread.h |1 +
ksrc/nucleus/synch.c | 11 ---
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/include/nucleus/thread.h b/include/nucleus/thread.h
index 389a12b..1124eb4 100644
--- a/include/nucleus/thread.h
+++ b/include/nucleus/thread.h
@@ -62,6 +62,7 @@
#define XNFPU 0x0010 /**< Thread uses FPU */
#define XNSHADOW 0x0020 /**< Shadow thread */
#define XNROOT0x0040 /**< Root thread (that is, Linux/IDLE) */
+#define XNSWREP 0x0080 /**< Mode switch already reported */
/*! @} */ /* Ends doxygen comment group: nucleus_state_flags */
diff --git a/ksrc/nucleus/synch.c b/ksrc/nucleus/synch.c
index 816c7ab..1a9bbb4 100644
--- a/ksrc/nucleus/synch.c
+++ b/ksrc/nucleus/synch.c
@@ -987,9 +987,12 @@ EXPORT_SYMBOL_GPL(xnsynch_release_all_ownerships);
*/
void xnsynch_detect_relaxed_owner(struct xnsynch *synch, struct xnthread
*sleeper)
{
- if (xnthread_test_state(sleeper, XNTRAPSW) &&
- xnthread_test_state(synch->owner, XNRELAX))
+ if (xnthread_test_state(sleeper, XNTRAPSW|XNSWREP) == XNTRAPSW &&
+ xnthread_test_state(synch->owner, XNRELAX)) {
+ xnthread_set_state(sleeper, XNSWREP);
xnshadow_send_sig(sleeper, SIGXCPU, 0, 1);
+ } else
+ xnthread_clear_state(sleeper, XNSWREP);
}
/*
@@ -1010,8 +1013,10 @@ void xnsynch_detect_claimed_relax(struct xnthread *owner)
for (ht = getheadpq(&synch->pendq); ht != NULL;
ht = nextpq(&synch->pendq, ht)) {
sleeper = link2thread(ht, plink);
- if (xnthread_test_state(sleeper, XNRELAX))
+ if (xnthread_test_state(sleeper, XNRELAX)) {
+ xnthread_set_state(sleeper, XNSWREP);
xnshadow_send_sig(sleeper, SIGXCPU, 0, 1);
+ }
}
}
}
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[Xenomai-git] Jan Kiszka : nucleus: Fix endless loop of DEBUG_SYNCH_RELAX
Module: xenomai-jki
Branch: for-upstream
Commit: e6b0910e2eb0178120b9f8170420e760516c3cbb
URL:
http://git.xenomai.org/?p=xenomai-jki.git;a=commit;h=e6b0910e2eb0178120b9f8170420e760516c3cbb
Author: Jan Kiszka
Date: Wed Nov 11 10:35:27 2009 +0100
nucleus: Fix endless loop of DEBUG_SYNCH_RELAX
When a thread is about to block on a mutex resource that is currently
held by a relaxed thread, it will receive SIGXCPU if the relaxed owner
debugging feature is enable. But after the signal is delivered and
handled, the sleeper will restart the mutex service and then receive the
same signal over and over again.
Fix this fatal loop by temporarily disabling the warning for the sleeper
after the first delivery, but also rearming it for the next run right
after that. This will still cause re-deliveries for the same blocking
call if the sleeper may fall out due to a different signal delivery. But
endless loops will be avoided and the solution is kept simple.
Signed-off-by: Jan Kiszka
---
include/nucleus/thread.h |1 +
ksrc/nucleus/synch.c | 11 ---
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/include/nucleus/thread.h b/include/nucleus/thread.h
index 389a12b..1124eb4 100644
--- a/include/nucleus/thread.h
+++ b/include/nucleus/thread.h
@@ -62,6 +62,7 @@
#define XNFPU 0x0010 /**< Thread uses FPU */
#define XNSHADOW 0x0020 /**< Shadow thread */
#define XNROOT0x0040 /**< Root thread (that is, Linux/IDLE) */
+#define XNSWREP 0x0080 /**< Mode switch already reported */
/*! @} */ /* Ends doxygen comment group: nucleus_state_flags */
diff --git a/ksrc/nucleus/synch.c b/ksrc/nucleus/synch.c
index 816c7ab..84d5164 100644
--- a/ksrc/nucleus/synch.c
+++ b/ksrc/nucleus/synch.c
@@ -987,9 +987,12 @@ EXPORT_SYMBOL_GPL(xnsynch_release_all_ownerships);
*/
void xnsynch_detect_relaxed_owner(struct xnsynch *synch, struct xnthread
*sleeper)
{
- if (xnthread_test_state(sleeper, XNTRAPSW) &&
- xnthread_test_state(synch->owner, XNRELAX))
+ if (xnthread_test_state(sleeper, XNTRAPSW|XNSWREP) == XNTRAPSW &&
+ xnthread_test_state(synch->owner, XNRELAX)) {
+ xnthread_set_state(sleeper, XNSWREP);
xnshadow_send_sig(sleeper, SIGXCPU, 0, 1);
+ } else
+ xnthread_clear_state(sleeper, XNSWREP);
}
/*
@@ -1010,8 +1013,10 @@ void xnsynch_detect_claimed_relax(struct xnthread *owner)
for (ht = getheadpq(&synch->pendq); ht != NULL;
ht = nextpq(&synch->pendq, ht)) {
sleeper = link2thread(ht, plink);
- if (xnthread_test_state(sleeper, XNRELAX))
+ if (xnthread_test_state(sleeper, XNRELAX)) {
+ xnthread_set_state(sleeper, XNSWREP);
xnshadow_send_sig(sleeper, SIGXCPU, 0, 1);
+ }
}
}
}
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