File 1097-erts-Fix-bug-when-resetting-call_time-memo... of Package erlang

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File 1097-erts-Fix-bug-when-resetting-call_time-memory-while-t.patch of Package erlang (Revision 58ddfd9fcf4c281c82656d8c2d2a71df)

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From 9e1fa96c2850ae360969331a20f1b7dbcda2fff8 Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Wed, 2 Oct 2024 17:21:04 +0200
Subject: [PATCH] erts: Fix bug when resetting call_time/memory while tracing

Clearing the BpDataCallTrace hashes under the feet of executing
processes could cause crash.

Instead allocate a new cleared BpDataCallTrace
for the staged breakpoint.
---
 erts/emulator/beam/beam_bp.c                 | 42 ++++++------
 erts/emulator/beam/beam_bp.h                 |  2 +-
 erts/emulator/test/trace_call_time_SUITE.erl | 70 +++++++++++++++++++-
 3 files changed, 92 insertions(+), 22 deletions(-)

diff --git a/erts/emulator/beam/beam_bp.c b/erts/emulator/beam/beam_bp.c
index 7f105ce7c4..50c8c6eb90 100644
--- a/erts/emulator/beam/beam_bp.c
+++ b/erts/emulator/beam/beam_bp.c
@@ -121,6 +121,7 @@ static GenericBpData* check_break(const ErtsCodeInfo *ci, Uint break_flags);
 
 static void bp_meta_unref(BpMetaTracer *bmt);
 static void bp_count_unref(BpCount *bcp);
+static BpDataTime* bp_time_alloc(void);
 static void bp_time_unref(BpDataTime *bdt);
 static void consolidate_bp_data(Module *modp, ErtsCodeInfo *ci, int local);
 static void uninstall_breakpoint(ErtsCodeInfo *ci);
@@ -380,7 +381,6 @@ consolidate_bp_data(Module* modp, ErtsCodeInfo *ci_rw, int local)
     if (flags & ERTS_BPF_TIME_TRACE) {
 	dst->time = src->time;
 	erts_refc_inc(&dst->time->refc, 1);
-	ASSERT(dst->time->hash);
     }
 }
 
@@ -1308,6 +1308,11 @@ static void bp_hash_delete(bp_time_hash_t *hash) {
     hash->item = NULL;
 }
 
+static void bp_hash_reset(BpDataTime** bdt_p) {
+    bp_time_unref(*bdt_p);
+    *bdt_p = bp_time_alloc();
+}
+
 void erts_schedule_time_break(Process *p, Uint schedule) {
     process_breakpoint_time_t *pbt = NULL;
     bp_data_time_item_t sitem, *item = NULL;
@@ -1388,6 +1393,7 @@ set_break(BpFunctions* f, Binary *match_spec, Uint break_flags,
     }
 }
 
+
 static void
 set_function_break(ErtsCodeInfo *ci, Binary *match_spec, Uint break_flags,
 		   enum erts_break_op count_op, ErtsTracer tracer)
@@ -1450,17 +1456,11 @@ set_function_break(ErtsCodeInfo *ci, Binary *match_spec, Uint break_flags,
 	ASSERT((bp->flags & ~ERTS_BPF_ALL) == 0);
 	return;
     } else if (common & ERTS_BPF_TIME_TRACE) {
-	BpDataTime* bdt = bp->time;
-	Uint i = 0;
-
 	if (count_op == ERTS_BREAK_PAUSE) {
 	    bp->flags &= ~ERTS_BPF_TIME_TRACE_ACTIVE;
 	} else {
 	    bp->flags |= ERTS_BPF_TIME_TRACE_ACTIVE;
-	    for (i = 0; i < bdt->n; i++) {
-		bp_hash_delete(&(bdt->hash[i]));
-		bp_hash_init(&(bdt->hash[i]), 32);
-	    }
+            bp_hash_reset(&bp->time);
 	}
 	ASSERT((bp->flags & ~ERTS_BPF_ALL) == 0);
 	return;
@@ -1492,18 +1492,8 @@ set_function_break(ErtsCodeInfo *ci, Binary *match_spec, Uint break_flags,
 	erts_atomic_init_nob(&bcp->acount, 0);
 	bp->count = bcp;
     } else if (break_flags & ERTS_BPF_TIME_TRACE) {
-	BpDataTime* bdt;
-	Uint i;
-
 	ASSERT((bp->flags & ERTS_BPF_TIME_TRACE) == 0);
-	bdt = Alloc(sizeof(BpDataTime));
-	erts_refc_init(&bdt->refc, 1);
-	bdt->n = erts_no_schedulers + 1;
-	bdt->hash = Alloc(sizeof(bp_time_hash_t)*(bdt->n));
-	for (i = 0; i < bdt->n; i++) {
-	    bp_hash_init(&(bdt->hash[i]), 32);
-	}
-	bp->time = bdt;
+	bp->time = bp_time_alloc();
     }
 
     bp->flags |= break_flags;
@@ -1578,6 +1568,19 @@ bp_count_unref(BpCount* bcp)
     }
 }
 
+static BpDataTime* bp_time_alloc(void)
+{
+    const Uint n = erts_no_schedulers + 1;
+    BpDataTime *bdt = Alloc(offsetof(BpDataTime,hash) +
+                            sizeof(bp_time_hash_t)*n);
+    bdt->n = n;
+    erts_refc_init(&bdt->refc, 1);
+    for (Uint i = 0; i < n; i++) {
+        bp_hash_init(&(bdt->hash[i]), 32);
+    }
+    return bdt;
+}
+
 static void
 bp_time_unref(BpDataTime* bdt)
 {
@@ -1587,7 +1590,6 @@ bp_time_unref(BpDataTime* bdt)
 	for (i = 0; i < bdt->n; ++i) {
 	    bp_hash_delete(&(bdt->hash[i]));
 	}
-	Free(bdt->hash);
 	Free(bdt);
     }
 }
diff --git a/erts/emulator/beam/beam_bp.h b/erts/emulator/beam/beam_bp.h
index 3688f08332..d9b786dd1f 100644
--- a/erts/emulator/beam/beam_bp.h
+++ b/erts/emulator/beam/beam_bp.h
@@ -40,8 +40,8 @@ typedef struct {
 
 typedef struct bp_data_time {     /* Call time */
     Uint n;
-    bp_time_hash_t *hash;
     erts_refc_t refc;
+    bp_time_hash_t hash[1];
 } BpDataTime;
 
 typedef struct {
diff --git a/erts/emulator/test/trace_call_time_SUITE.erl b/erts/emulator/test/trace_call_time_SUITE.erl
index 2da660c881..df22e3d0f1 100644
--- a/erts/emulator/test/trace_call_time_SUITE.erl
+++ b/erts/emulator/test/trace_call_time_SUITE.erl
@@ -35,7 +35,7 @@
 
 -export([seq/3, seq_r/3]).
 -export([loaded/1, a_function/1, a_called_function/1, dec/1, nif_dec/1, dead_tracer/1,
-        return_stop/1,catch_crash/1]).
+        return_stop/1,reset/1,catch_crash/1]).
 
 -define(US_ERROR, 10000).
 -define(R_ERROR, 0.8).
@@ -91,6 +91,7 @@ all() ->
      disable_ongoing,
      apply_bif_bug,
      combo, bif, nif, called_function, dead_tracer, return_stop,
+     reset,
      catch_crash].
 
 %% Tests basic call time trace
@@ -633,6 +634,73 @@ spinner(N) ->
 quicky() ->
     done.
 
+%% OTP-19269: Verify call_time is reset correctly
+%% while traced functions are called.
+reset(_Config) ->
+    erlang:trace_pattern({'_','_','_'}, false, [call_time]),
+
+    CallTimeReader = fun({P,Cnt,_,_}) -> {P,Cnt} end,
+    reset_do(call_time, true, CallTimeReader),
+    reset_do(call_time, restart, CallTimeReader),
+    ok.
+
+reset_do(TraceType, ResetArg, InfoReader) ->
+    %%
+    1 = erlang:trace_pattern({?MODULE,aaa, 0}, true, [TraceType]),
+    1 = erlang:trace_pattern({?MODULE,bbb, 0}, true, [TraceType]),
+
+    Np = erlang:system_info(schedulers_online),
+    Tester = self(),
+    Pids = [begin
+                Pid = spawn_opt(fun() ->
+                                        receive go -> ok end,
+                                        aaa(),
+                                        bbb(),
+                                        Tester ! {running, self()},
+                                        loop_aaa_bbb()
+                                end,
+                                [link, {scheduler,I}]),
+                erlang:trace(Pid, true, [call]),
+                Pid ! go,
+                Pid
+            end
+            || I <- lists:seq(1,Np)],
+
+    %% Wait for all to make at least one traced call
+    [receive {running, P} -> ok end || P <- Pids],
+
+    {TraceType, AAA1} = erlang:trace_info({?MODULE,aaa,0}, TraceType),
+
+    io:format("Reset trace counters for aaa.\n", []),
+    1 = erlang:trace_pattern({?MODULE,aaa, 0}, ResetArg, [TraceType]),
+
+    {TraceType, AAA2} = erlang:trace_info({?MODULE,aaa,0}, TraceType),
+    {TraceType, BBB} = erlang:trace_info({?MODULE,bbb,0}, TraceType),
+
+    %% Verify counters are sane
+    lists:zipwith3(fun({P, ACnt1}=A1,
+                       {P, ACnt2}=A2,
+                       {P, BCnt}=B) ->
+                           io:format("A1=~p A2=~p B=~p\n", [A1,A2,B]),
+                           true = (ACnt1+ACnt2 =< BCnt)
+                  end,
+                  lists:sort(lists:map(InfoReader, AAA1)),
+                  lists:sort(lists:map(InfoReader, AAA2)),
+                  lists:sort(lists:map(InfoReader, BBB))),
+
+    [P ! die || P <- Pids],
+    1 = erlang:trace_pattern({?MODULE,aaa, 0}, false, [TraceType]),
+    1 = erlang:trace_pattern({?MODULE,bbb, 0}, false, [TraceType]),
+    ok.
+
+loop_aaa_bbb() ->
+    aaa = aaa(),
+    bbb = bbb(),
+    receive die -> ok
+    after 0 -> loop_aaa_bbb()
+    end.
+
+
 %% OTP-16994: next_catch returned a bogus stack pointer when call_time tracing
 %% was enabled, crashing the emulator.
 catch_crash(_Config) ->
-- 
2.43.0

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File 1097-erts-Fix-bug-when-resetting-call_time-memory-while-t.patch of Package erlang (Revision 58ddfd9fcf4c281c82656d8c2d2a71df)

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