This patch fixes resume/unhibernate on GPROF kernels where kgmon(8)
has activated kernel profiling.
I think the problem is that code called from cpu_hatch() does not play
nicely with _mcount(), so GPROF kernels crash during resume. I can't
point you to which code in particular, but keeping all CPUs out of
_mcount() until the primary CPU has completed resume/unhibernate fixes
the crash.
ok?
Index: sys/lib/libkern/mcount.c
===================================================================
RCS file: /cvs/src/sys/lib/libkern/mcount.c,v
retrieving revision 1.14
diff -u -p -r1.14 mcount.c
--- sys/lib/libkern/mcount.c 11 Jan 2022 09:21:34 -0000 1.14
+++ sys/lib/libkern/mcount.c 9 Jul 2023 17:49:55 -0000
@@ -33,6 +33,32 @@
#include <sys/param.h>
#include <sys/gmon.h>
+#ifdef _KERNEL
+#ifdef SUSPEND
+#include <sys/atomic.h>
+
+#include <lib/libkern/libkern.h> /* KASSERT */
+
+volatile int mcount_disabled;
+
+void
+mcount_disable(void)
+{
+ KASSERT(CPU_IS_PRIMARY(curcpu()));
+ mcount_disabled = 1;
+ membar_producer();
+}
+
+void
+mcount_enable(void)
+{
+ KASSERT(CPU_IS_PRIMARY(curcpu()));
+ mcount_disabled = 0;
+ membar_producer();
+}
+#endif /* SUSPEND */
+#endif /* _KERNEL */
+
/*
* mcount is called on entry to each function compiled with the profiling
* switch set. _mcount(), which is declared in a machine-dependent way
@@ -63,7 +89,10 @@ _MCOUNT_DECL(u_long frompc, u_long selfp
*/
if (gmoninit == 0)
return;
-
+#ifdef SUSPEND
+ if (mcount_disabled)
+ return;
+#endif
if ((p = curcpu()->ci_gmon) == NULL)
return;
#else
Index: sys/kern/subr_suspend.c
===================================================================
RCS file: /cvs/src/sys/kern/subr_suspend.c,v
retrieving revision 1.15
diff -u -p -r1.15 subr_suspend.c
--- sys/kern/subr_suspend.c 2 Jul 2023 19:02:27 -0000 1.15
+++ sys/kern/subr_suspend.c 9 Jul 2023 17:49:55 -0000
@@ -26,6 +26,9 @@
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <dev/wscons/wsdisplayvar.h>
+#ifdef GPROF
+#include <sys/gmon.h>
+#endif
#ifdef HIBERNATE
#include <sys/hibernate.h>
#endif
@@ -63,6 +66,9 @@ top:
if (sleep_showstate(v, sleepmode))
return EOPNOTSUPP;
+#ifdef GPROF
+ mcount_disable();
+#endif
#if NWSDISPLAY > 0
wsdisplay_suspend();
#endif
@@ -192,6 +198,9 @@ fail_hiballoc:
start_periodic_resettodr();
#if NWSDISPLAY > 0
wsdisplay_resume();
+#endif
+#ifdef GPROF
+ mcount_enable();
#endif
sys_sync(curproc, NULL, NULL);
if (cpu_setperf != NULL)
Index: sys/sys/gmon.h
===================================================================
RCS file: /cvs/src/sys/sys/gmon.h,v
retrieving revision 1.9
diff -u -p -r1.9 gmon.h
--- sys/sys/gmon.h 11 Jan 2022 23:59:55 -0000 1.9
+++ sys/sys/gmon.h 9 Jul 2023 17:49:55 -0000
@@ -158,6 +158,10 @@ struct gmonparam {
#ifdef _KERNEL
extern int gmoninit; /* Is the kernel ready for being profiled? */
+#ifdef SUSPEND
+void mcount_disable(void);
+void mcount_enable(void);
+#endif
#else /* !_KERNEL */
#include <sys/cdefs.h>
Index: lib/libc/gmon/mcount.c
===================================================================
RCS file: /cvs/src/lib/libc/gmon/mcount.c,v
retrieving revision 1.16
diff -u -p -r1.16 mcount.c
--- lib/libc/gmon/mcount.c 11 Jan 2022 09:21:34 -0000 1.16
+++ lib/libc/gmon/mcount.c 9 Jul 2023 17:49:55 -0000
@@ -31,6 +31,32 @@
#include <sys/types.h>
#include <sys/gmon.h>
+#ifdef _KERNEL
+#ifdef SUSPEND
+#include <sys/atomic.h>
+
+#include <lib/libkern/libkern.h> /* KASSERT */
+
+volatile int mcount_disabled;
+
+void
+mcount_disable(void)
+{
+ KASSERT(CPU_IS_PRIMARY(curcpu()));
+ mcount_disabled = 1;
+ membar_producer();
+}
+
+void
+mcount_enable(void)
+{
+ KASSERT(CPU_IS_PRIMARY(curcpu()));
+ mcount_disabled = 0;
+ membar_producer();
+}
+#endif /* SUSPEND */
+#endif /* _KERNEL */
+
/*
* mcount is called on entry to each function compiled with the profiling
* switch set. _mcount(), which is declared in a machine-dependent way
@@ -61,7 +87,10 @@ _MCOUNT_DECL(u_long frompc, u_long selfp
*/
if (gmoninit == 0)
return;
-
+#ifdef SUSPEND
+ if (mcount_disabled)
+ return;
+#endif
if ((p = curcpu()->ci_gmon) == NULL)
return;
#else
