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authorBjörn-Egil Dahlberg <[email protected]>2016-06-13 16:55:55 +0200
committerBjörn-Egil Dahlberg <[email protected]>2016-06-13 17:16:21 +0200
commit8c19f3d39ff848817e8032f081577afbd5e75493 (patch)
tree5987109be046d419848e9319dfdd1a0518682515
parent99b379365981e14e2c8dde7b1a337c8ff856bd4a (diff)
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erts: Fix profile runnable processes race
-rw-r--r--erts/emulator/beam/erl_trace.c36
1 files changed, 22 insertions, 14 deletions
diff --git a/erts/emulator/beam/erl_trace.c b/erts/emulator/beam/erl_trace.c
index 3dca58d60b..4cf38bf894 100644
--- a/erts/emulator/beam/erl_trace.c
+++ b/erts/emulator/beam/erl_trace.c
@@ -2115,32 +2115,36 @@ profile_runnable_proc(Process *p, Eterm status){
Eterm *hp, msg;
Eterm where = am_undefined;
ErlHeapFragment *bp = NULL;
- int use_current = 1;
+ BeamInstr *current = NULL;
#ifndef ERTS_SMP
#define LOCAL_HEAP_SIZE (4 + 6 + ERTS_TRACE_PATCH_TS_MAX_SIZE)
-
DeclareTmpHeapNoproc(local_heap,LOCAL_HEAP_SIZE);
UseTmpHeapNoproc(LOCAL_HEAP_SIZE);
hp = local_heap;
#else
+ ErtsThrPrgrDelayHandle dhndl;
Uint hsz = 4 + 6 + patch_ts_size(erts_system_profile_ts_type)-1;
#endif
-
- if (ERTS_PROC_IS_EXITING(p)) {
- use_current = 0;
- /* could probably set 'where' to 'exiting' here,
- * though it's not documented as such */
- } else {
- if (!p->current) {
- p->current = find_function_from_pc(p->i);
+ /* Assumptions:
+ * We possibly don't have the MAIN_LOCK for the process p here.
+ * We assume that we can read from p->current and p->i atomically
+ */
+#ifdef ERTS_SMP
+ dhndl = erts_thr_progress_unmanaged_delay(); /* suspend purge operations */
+#endif
+
+ if (!ERTS_PROC_IS_EXITING(p)) {
+ if (p->current) {
+ current = p->current;
+ } else {
+ current = find_function_from_pc(p->i);
}
- use_current = p->current != NULL;
}
#ifdef ERTS_SMP
- if (!use_current) {
+ if (!current) {
hsz -= 4;
}
@@ -2148,11 +2152,15 @@ profile_runnable_proc(Process *p, Eterm status){
hp = bp->mem;
#endif
- if (use_current) {
- where = TUPLE3(hp, p->current[0], p->current[1], make_small(p->current[2])); hp += 4;
+ if (current) {
+ where = TUPLE3(hp, current[0], current[1], make_small(current[2])); hp += 4;
} else {
where = make_small(0);
}
+
+#ifdef ERTS_SMP
+ erts_thr_progress_unmanaged_continue(dhndl);
+#endif
erts_smp_mtx_lock(&smq_mtx);