From 8f26c0037dd08b5b55f7cb38168dcc61ef904b53 Mon Sep 17 00:00:00 2001
From: Christian Hergert <chergert@redhat.com>
Date: Mon, 28 Aug 2023 14:56:39 -0700
Subject: [PATCH] libsysprof: sniff various forms of kernel process names

This is by no means perfect, but it gets the kernel tasks running on my
machine out of the profiles. We will no doubt need to add more in the
future, or find a way to record a flag for that in the capture format.
---
 src/libsysprof/sysprof-process-info.c   |  3 +++
 src/libsysprof/sysprof-symbol-private.h |  1 +
 src/libsysprof/sysprof-symbol.c         | 17 +++++++++++++++++
 3 files changed, 21 insertions(+)

diff --git a/src/libsysprof/sysprof-process-info.c b/src/libsysprof/sysprof-process-info.c
index fc35d981..795ce438 100644
--- a/src/libsysprof/sysprof-process-info.c
+++ b/src/libsysprof/sysprof-process-info.c
@@ -51,6 +51,9 @@ sysprof_process_info_new (SysprofMountNamespace *mount_namespace,
                                                0, 0,
                                                SYSPROF_SYMBOL_KIND_PROCESS);
 
+  if (pid == 0)
+    self->fallback_symbol->is_kernel_process = TRUE;
+
   if (pid > 0)
     egg_bitset_add (self->thread_ids, pid);
 
diff --git a/src/libsysprof/sysprof-symbol-private.h b/src/libsysprof/sysprof-symbol-private.h
index d6085bc3..331a5f45 100644
--- a/src/libsysprof/sysprof-symbol-private.h
+++ b/src/libsysprof/sysprof-symbol-private.h
@@ -41,6 +41,7 @@ struct _SysprofSymbol
 
   guint kind : 3;
   guint is_fallback : 1;
+  guint is_kernel_process : 1;
 };
 
 SysprofSymbol *_sysprof_symbol_new (GRefString       *name,
diff --git a/src/libsysprof/sysprof-symbol.c b/src/libsysprof/sysprof-symbol.c
index ed09d216..7524e3a3 100644
--- a/src/libsysprof/sysprof-symbol.c
+++ b/src/libsysprof/sysprof-symbol.c
@@ -151,6 +151,20 @@ sysprof_symbol_get_binary_path (SysprofSymbol *self)
   return self->binary_path;
 }
 
+static gboolean
+sniff_maybe_kernel_process (const char *str)
+{
+  if (g_str_has_prefix (str, "kworker/") ||
+      g_str_equal (str, "rcu_preempt") ||
+      g_str_has_prefix (str, "migration/") ||
+      g_str_has_prefix (str, "dmcrypt_write/") ||
+      g_str_has_prefix (str, "hwrng") ||
+      g_str_has_prefix (str, "ksoftirqd/"))
+    return TRUE;
+
+  return FALSE;
+}
+
 SysprofSymbol *
 _sysprof_symbol_new (GRefString        *name,
                      GRefString        *binary_path,
@@ -176,6 +190,9 @@ _sysprof_symbol_new (GRefString        *name,
   self->simple_hash = g_str_hash (name);
   self->kind = kind;
 
+  if (self->kind == SYSPROF_SYMBOL_KIND_PROCESS)
+    self->is_kernel_process = sniff_maybe_kernel_process (name);
+
   if (binary_nick != NULL)
     self->simple_hash ^= g_str_hash (binary_nick);