commit ba64f031f2435aad5a85f8f37dbbe2a982cbbe6b
author Philip Gladstone <pjsg@users.noreply.github.com> Fri Sep 20 01:12:01 2019 -0400
committer yonghong-song <yhs@fb.com> Thu Sep 19 22:12:01 2019 -0700
tree ca19438c78a7ed417fcc67b9459a77b98b3ee5fa
parent c99c7c4063213f4bb6e8347f9b4d36ed316aa8c9

Fixes #2518 -- weird behaviour of lookup_or_init (#2520)

* Allow lookup_or_init to return NULL (rather than just returning from the current function)
* Fixed a couple of bad edits found when running tests. Also fixed a bug in the
test runner. Also fixed a bug in libbcc where the python signature did not match
the actual implementation.

tools/lib/ucalls.py

diff --git a/tools/lib/ucalls.py b/tools/lib/ucalls.py
index d072af0..1175195 100755
--- a/tools/lib/ucalls.py
+++ b/tools/lib/ucalls.py
@@ -164,7 +164,9 @@
                    (void *)method);
 #ifndef LATENCY
     valp = counts.lookup_or_init(&data.method, &val);
-    ++(*valp);
+    if (valp) {
+        ++(*valp);
+    }
 #endif
 #ifdef LATENCY
     entry.update(&data, &timestamp);
@@ -189,8 +191,10 @@
         return 0;   // missed the entry event
     }
     info = times.lookup_or_init(&data.method, &zero);
-    info->num_calls += 1;
-    info->total_ns += bpf_ktime_get_ns() - *entry_timestamp;
+    if (info) {
+        info->num_calls += 1;
+        info->total_ns += bpf_ktime_get_ns() - *entry_timestamp;
+    }
     entry.delete(&data);
     return 0;
 }
@@ -210,7 +214,9 @@
 #endif
 #ifndef LATENCY
     valp = syscounts.lookup_or_init(&id, &val);
-    ++(*valp);
+    if (valp) {
+        ++(*valp);
+    }
 #endif
     return 0;
 }
@@ -227,8 +233,10 @@
     }
     id = e->id;
     info = systimes.lookup_or_init(&id, &zero);
-    info->num_calls += 1;
-    info->total_ns += bpf_ktime_get_ns() - e->timestamp;
+    if (info) {
+        info->num_calls += 1;
+        info->total_ns += bpf_ktime_get_ns() - e->timestamp;
+    }
     sysentry.delete(&pid);
     return 0;
 }

tools/lib/uflow.py

diff --git a/tools/lib/uflow.py b/tools/lib/uflow.py
index 63fab87..f904533 100755
--- a/tools/lib/uflow.py
+++ b/tools/lib/uflow.py
@@ -89,6 +89,9 @@
 
     data.pid = bpf_get_current_pid_tgid();
     depth = entry.lookup_or_init(&data.pid, &zero);
+    if (!depth) {
+        depth = &zero;
+    }
     data.depth = DEPTH;
     UPDATE
 

tools/lib/uobjnew.py

diff --git a/tools/lib/uobjnew.py b/tools/lib/uobjnew.py
index 85f5768..63dd80a 100755
--- a/tools/lib/uobjnew.py
+++ b/tools/lib/uobjnew.py
@@ -80,8 +80,10 @@
     struct val_t *valp, zero = {};
     key.size = size;
     valp = allocs.lookup_or_init(&key, &zero);
-    valp->total_size += size;
-    valp->num_allocs += 1;
+    if (valp) {
+        valp->total_size += size;
+        valp->num_allocs += 1;
+    }
     return 0;
 }
     """
@@ -98,8 +100,10 @@
     bpf_usdt_readarg(4, ctx, &size);
     bpf_probe_read(&key.name, sizeof(key.name), (void *)classptr);
     valp = allocs.lookup_or_init(&key, &zero);
-    valp->total_size += size;
-    valp->num_allocs += 1;
+    if (valp) {
+        valp->total_size += size;
+        valp->num_allocs += 1;
+    }
     return 0;
 }
     """
@@ -115,8 +119,10 @@
     u64 size = 0;
     bpf_usdt_readarg(1, ctx, &size);
     valp = allocs.lookup_or_init(&key, &zero);
-    valp->total_size += size;
-    valp->num_allocs += 1;
+    if (valp) {
+        valp->total_size += size;
+        valp->num_allocs += 1;
+    }
     return 0;
 }
     """
@@ -128,7 +134,9 @@
     bpf_usdt_readarg(1, ctx, &classptr);
     bpf_probe_read(&key.name, sizeof(key.name), (void *)classptr);
     valp = allocs.lookup_or_init(&key, &zero);
-    valp->num_allocs += 1;  // We don't know the size, unfortunately
+    if (valp) {
+        valp->num_allocs += 1;  // We don't know the size, unfortunately
+    }
     return 0;
 }
     """
@@ -146,7 +154,9 @@
     struct key_t key = { .name = "<ALL>" };
     struct val_t *valp, zero = {};
     valp = allocs.lookup_or_init(&key, &zero);
-    valp->num_allocs += 1;
+    if (valp) {
+        valp->num_allocs += 1;
+    }
     return 0;
 }
     """

tools/lib/ustat.py

diff --git a/tools/lib/ustat.py b/tools/lib/ustat.py
index 1edc985..bd5b98b 100755
--- a/tools/lib/ustat.py
+++ b/tools/lib/ustat.py
@@ -94,7 +94,9 @@
     u64 *valp, zero = 0;
     u32 tgid = bpf_get_current_pid_tgid() >> 32;
     valp = %s_%s_counts.lookup_or_init(&tgid, &zero);
-    ++(*valp);
+    if (valp) {
+        ++(*valp);
+    }
     return 0;
 }
         """