From b977f96d0a414e76d4c544f65791919dde1bc57e Mon Sep 17 00:00:00 2001
From: Michael Jeanson <mjeanson@efficios.com>
Date: Mon, 17 Oct 2022 13:49:51 -0400
Subject: [PATCH] fix: mm/slab_common: drop kmem_alloc & avoid dereferencing
 fields when not using (v6.1)

See uptream commit:

  commit 2c1d697fb8ba6d2d44f914d4268ae1ccdf025f1b
  Author: Hyeonggon Yoo <42.hyeyoo@gmail.com>
  Date:   Wed Aug 17 19:18:24 2022 +0900

    mm/slab_common: drop kmem_alloc & avoid dereferencing fields when not using

    Drop kmem_alloc event class, and define kmalloc and kmem_cache_alloc
    using TRACE_EVENT() macro.

    And then this patch does:
       - Do not pass pointer to struct kmem_cache to trace_kmalloc.
         gfp flag is enough to know if it's accounted or not.
       - Avoid dereferencing s->object_size and s->size when not using kmem_cache_alloc event.
       - Avoid dereferencing s->name in when not using kmem_cache_free event.
       - Adjust s->size to SLOB_UNITS(s->size) * SLOB_UNIT in SLOB

Upstream-Status: Backport [commit b977f96d0a414e76d4c544f]

Change-Id: Icd7925731ed4a737699c3746cb7bb7760a4e8009
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 include/instrumentation/events/kmem.h | 156 ++++++++++++++++++--------
 1 file changed, 111 insertions(+), 45 deletions(-)

diff --git a/include/instrumentation/events/kmem.h b/include/instrumentation/events/kmem.h
index 219533a1..0f5bd8e6 100644
--- a/include/instrumentation/events/kmem.h
+++ b/include/instrumentation/events/kmem.h
@@ -10,9 +10,58 @@
 #include <lttng/kernel-version.h>
 
 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(6,0,0))
-
 #include <../../mm/slab.h>
+#endif
+
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(6,1,0))
+LTTNG_TRACEPOINT_EVENT_MAP(kmalloc,
+
+	kmem_kmalloc,
+
+	TP_PROTO(unsigned long call_site,
+		 const void *ptr,
+		 size_t bytes_req,
+		 size_t bytes_alloc,
+		 gfp_t gfp_flags,
+		 int node),
+
+	TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags, node),
+
+	TP_FIELDS(
+		ctf_integer_hex(unsigned long, call_site, call_site)
+		ctf_integer_hex(const void *, ptr, ptr)
+		ctf_integer(size_t, bytes_req, bytes_req)
+		ctf_integer(size_t, bytes_alloc, bytes_alloc)
+		ctf_integer(gfp_t, gfp_flags, gfp_flags)
+		ctf_integer(int, node, node)
+		ctf_integer(bool, accounted, (IS_ENABLED(CONFIG_MEMCG_KMEM) &&
+			(gfp_flags & __GFP_ACCOUNT) ? true : false))
+	)
+)
+
+LTTNG_TRACEPOINT_EVENT(kmem_cache_alloc,
+
+	TP_PROTO(unsigned long call_site,
+		 const void *ptr,
+		 struct kmem_cache *s,
+		 gfp_t gfp_flags,
+		 int node),
+
+	TP_ARGS(call_site, ptr, s, gfp_flags, node),
 
+	TP_FIELDS(
+		ctf_integer_hex(unsigned long, call_site, call_site)
+		ctf_integer_hex(const void *, ptr, ptr)
+		ctf_integer(size_t, bytes_req, s->object_size)
+		ctf_integer(size_t, bytes_alloc, s->size)
+		ctf_integer(gfp_t, gfp_flags, gfp_flags)
+		ctf_integer(int, node, node)
+		ctf_integer(bool, accounted, IS_ENABLED(CONFIG_MEMCG_KMEM) ?
+			((gfp_flags & __GFP_ACCOUNT) ||
+			(s->flags & SLAB_ACCOUNT)) : false)
+	)
+)
+#elif (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(6,0,0))
 LTTNG_TRACEPOINT_EVENT_CLASS(kmem_alloc,
 
 	TP_PROTO(unsigned long call_site,
@@ -53,18 +102,16 @@ LTTNG_TRACEPOINT_EVENT_INSTANCE(kmem_alloc, kmem_cache_alloc,
 
 	TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags)
 )
-
-LTTNG_TRACEPOINT_EVENT_CLASS(kmem_alloc_node,
+#else
+LTTNG_TRACEPOINT_EVENT_CLASS(kmem_alloc,
 
 	TP_PROTO(unsigned long call_site,
 		 const void *ptr,
-		 struct kmem_cache *s,
 		 size_t bytes_req,
 		 size_t bytes_alloc,
-		 gfp_t gfp_flags,
-		 int node),
+		 gfp_t gfp_flags),
 
-	TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node),
+	TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags),
 
 	TP_FIELDS(
 		ctf_integer_hex(unsigned long, call_site, call_site)
@@ -72,42 +119,40 @@ LTTNG_TRACEPOINT_EVENT_CLASS(kmem_alloc_node,
 		ctf_integer(size_t, bytes_req, bytes_req)
 		ctf_integer(size_t, bytes_alloc, bytes_alloc)
 		ctf_integer(gfp_t, gfp_flags, gfp_flags)
-		ctf_integer(int, node, node)
-		ctf_integer(bool, accounted, IS_ENABLED(CONFIG_MEMCG_KMEM) ?
-			((gfp_flags & __GFP_ACCOUNT) ||
-			(s && s->flags & SLAB_ACCOUNT)) : false)
 	)
 )
 
-LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP(kmem_alloc_node, kmalloc_node,
+LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP(kmem_alloc, kmalloc,
 
-	kmem_kmalloc_node,
+	kmem_kmalloc,
 
 	TP_PROTO(unsigned long call_site, const void *ptr,
-		 struct kmem_cache *s, size_t bytes_req, size_t bytes_alloc,
-		 gfp_t gfp_flags, int node),
+		 size_t bytes_req, size_t bytes_alloc, gfp_t gfp_flags),
 
-	TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node)
+	TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags)
 )
 
-LTTNG_TRACEPOINT_EVENT_INSTANCE(kmem_alloc_node, kmem_cache_alloc_node,
+LTTNG_TRACEPOINT_EVENT_INSTANCE(kmem_alloc, kmem_cache_alloc,
 
 	TP_PROTO(unsigned long call_site, const void *ptr,
-		 struct kmem_cache *s, size_t bytes_req, size_t bytes_alloc,
-		 gfp_t gfp_flags, int node),
+		 size_t bytes_req, size_t bytes_alloc, gfp_t gfp_flags),
 
-	TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node)
+	TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags)
 )
-#else
-LTTNG_TRACEPOINT_EVENT_CLASS(kmem_alloc,
+#endif
+
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(6,0,0))
+LTTNG_TRACEPOINT_EVENT_CLASS(kmem_alloc_node,
 
 	TP_PROTO(unsigned long call_site,
 		 const void *ptr,
+		 struct kmem_cache *s,
 		 size_t bytes_req,
 		 size_t bytes_alloc,
-		 gfp_t gfp_flags),
+		 gfp_t gfp_flags,
+		 int node),
 
-	TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags),
+	TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node),
 
 	TP_FIELDS(
 		ctf_integer_hex(unsigned long, call_site, call_site)
@@ -115,27 +160,33 @@ LTTNG_TRACEPOINT_EVENT_CLASS(kmem_alloc,
 		ctf_integer(size_t, bytes_req, bytes_req)
 		ctf_integer(size_t, bytes_alloc, bytes_alloc)
 		ctf_integer(gfp_t, gfp_flags, gfp_flags)
+		ctf_integer(int, node, node)
+		ctf_integer(bool, accounted, IS_ENABLED(CONFIG_MEMCG_KMEM) ?
+			((gfp_flags & __GFP_ACCOUNT) ||
+			(s && s->flags & SLAB_ACCOUNT)) : false)
 	)
 )
 
-LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP(kmem_alloc, kmalloc,
+LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP(kmem_alloc_node, kmalloc_node,
 
-	kmem_kmalloc,
+	kmem_kmalloc_node,
 
 	TP_PROTO(unsigned long call_site, const void *ptr,
-		 size_t bytes_req, size_t bytes_alloc, gfp_t gfp_flags),
+		 struct kmem_cache *s, size_t bytes_req, size_t bytes_alloc,
+		 gfp_t gfp_flags, int node),
 
-	TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags)
+	TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node)
 )
 
-LTTNG_TRACEPOINT_EVENT_INSTANCE(kmem_alloc, kmem_cache_alloc,
+LTTNG_TRACEPOINT_EVENT_INSTANCE(kmem_alloc_node, kmem_cache_alloc_node,
 
 	TP_PROTO(unsigned long call_site, const void *ptr,
-		 size_t bytes_req, size_t bytes_alloc, gfp_t gfp_flags),
+		 struct kmem_cache *s, size_t bytes_req, size_t bytes_alloc,
+		 gfp_t gfp_flags, int node),
 
-	TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags)
+	TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node)
 )
-
+#else
 LTTNG_TRACEPOINT_EVENT_CLASS(kmem_alloc_node,
 
 	TP_PROTO(unsigned long call_site,
@@ -192,19 +243,6 @@ LTTNG_TRACEPOINT_EVENT_MAP(kfree,
 		ctf_integer_hex(const void *, ptr, ptr)
 	)
 )
-
-LTTNG_TRACEPOINT_EVENT(kmem_cache_free,
-
-	TP_PROTO(unsigned long call_site, const void *ptr, const char *name),
-
-	TP_ARGS(call_site, ptr, name),
-
-	TP_FIELDS(
-		ctf_integer_hex(unsigned long, call_site, call_site)
-		ctf_integer_hex(const void *, ptr, ptr)
-		ctf_string(name, name)
-	)
-)
 #else
 LTTNG_TRACEPOINT_EVENT_CLASS(kmem_free,
 
@@ -235,6 +273,34 @@ LTTNG_TRACEPOINT_EVENT_INSTANCE(kmem_free, kmem_cache_free,
 )
 #endif
 
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(6,1,0))
+LTTNG_TRACEPOINT_EVENT(kmem_cache_free,
+
+	TP_PROTO(unsigned long call_site, const void *ptr, const struct kmem_cache *s),
+
+	TP_ARGS(call_site, ptr, s),
+
+	TP_FIELDS(
+		ctf_integer_hex(unsigned long, call_site, call_site)
+		ctf_integer_hex(const void *, ptr, ptr)
+		ctf_string(name, s->name)
+	)
+)
+#elif (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,12,0))
+LTTNG_TRACEPOINT_EVENT(kmem_cache_free,
+
+	TP_PROTO(unsigned long call_site, const void *ptr, const char *name),
+
+	TP_ARGS(call_site, ptr, name),
+
+	TP_FIELDS(
+		ctf_integer_hex(unsigned long, call_site, call_site)
+		ctf_integer_hex(const void *, ptr, ptr)
+		ctf_string(name, name)
+	)
+)
+#endif
+
 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,3,0))
 LTTNG_TRACEPOINT_EVENT_MAP(mm_page_free, kmem_mm_page_free,
 #else
-- 
2.19.1