svn commit: r242361 - in head/sys: dev/hwpmc kern
Attilio Rao
attilio at FreeBSD.org
Tue Oct 30 15:10:51 UTC 2012
Author: attilio
Date: Tue Oct 30 15:10:50 2012
New Revision: 242361
URL: http://svn.freebsd.org/changeset/base/242361
Log:
Fixup r240246: hwpmc needs to retain the pinning until ASTs are not
executed. This means past the point where userret() is generally
executed.
Skip the td_pinned check if a callchain tracing is currently happening
and add a more robust check to pmc_capture_user_callchain() in order to
catch td_pinned leak past ast() in hwpmc case.
Reported and tested by: fabient
MFC after: 1 week
X-MFC: r240246
Modified:
head/sys/dev/hwpmc/hwpmc_mod.c
head/sys/kern/subr_trap.c
Modified: head/sys/dev/hwpmc/hwpmc_mod.c
==============================================================================
--- head/sys/dev/hwpmc/hwpmc_mod.c Tue Oct 30 13:22:39 2012 (r242360)
+++ head/sys/dev/hwpmc/hwpmc_mod.c Tue Oct 30 15:10:50 2012 (r242361)
@@ -4248,7 +4248,7 @@ pmc_capture_user_callchain(int cpu, int
("[pmc,%d] cpu %d didn't find a sample to collect", __LINE__,
cpu));
- KASSERT(td->td_pinned > 0,
+ KASSERT(td->td_pinned == 1,
("[pmc,%d] invalid td_pinned value", __LINE__));
sched_unpin(); /* Can migrate safely now. */
Modified: head/sys/kern/subr_trap.c
==============================================================================
--- head/sys/kern/subr_trap.c Tue Oct 30 13:22:39 2012 (r242360)
+++ head/sys/kern/subr_trap.c Tue Oct 30 15:10:50 2012 (r242361)
@@ -145,6 +145,11 @@ userret(struct thread *td, struct trapfr
/*
* Check for misbehavior.
+ *
+ * In case there is a callchain tracing ongoing because of
+ * hwpmc(4), skip the scheduler pinning check.
+ * hwpmc(4) subsystem, infact, will collect callchain informations
+ * at ast() checkpoint, which is past userret().
*/
WITNESS_WARN(WARN_PANIC, NULL, "userret: returning");
KASSERT(td->td_critnest == 0,
@@ -155,7 +160,7 @@ userret(struct thread *td, struct trapfr
("userret: Returning with pagefaults disabled"));
KASSERT((td->td_pflags & TDP_NOSLEEPING) == 0,
("userret: Returning with sleep disabled"));
- KASSERT(td->td_pinned == 0,
+ KASSERT(td->td_pinned == 0 || (td->td_pflags & TDP_CALLCHAIN) != 0,
("userret: Returning with with pinned thread"));
KASSERT(td->td_vp_reserv == 0,
("userret: Returning while holding vnode reservation"));
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