public inbox for [email protected]
 help / color / mirror / Atom feed
From: Suren Baghdasaryan <[email protected]>
To: [email protected]
Cc: [email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected]
Subject: [RFC PATCH 05/30] lib: code tagging framework
Date: Tue, 30 Aug 2022 14:48:54 -0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

Add basic infrastructure to support code tagging which stores tag common
information consisting of the module name, function, file name and line
number. Provide functions to register a new code tag type and navigate
between code tags.

Co-developed-by: Kent Overstreet <[email protected]>
Signed-off-by: Kent Overstreet <[email protected]>
Signed-off-by: Suren Baghdasaryan <[email protected]>
---
 include/linux/codetag.h |  71 ++++++++++++++
 lib/Kconfig.debug       |   4 +
 lib/Makefile            |   1 +
 lib/codetag.c           | 199 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 275 insertions(+)
 create mode 100644 include/linux/codetag.h
 create mode 100644 lib/codetag.c

diff --git a/include/linux/codetag.h b/include/linux/codetag.h
new file mode 100644
index 000000000000..a9d7adecc2a5
--- /dev/null
+++ b/include/linux/codetag.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * code tagging framework
+ */
+#ifndef _LINUX_CODETAG_H
+#define _LINUX_CODETAG_H
+
+#include <linux/types.h>
+
+struct codetag_iterator;
+struct codetag_type;
+struct seq_buf;
+struct module;
+
+/*
+ * An instance of this structure is created in a special ELF section at every
+ * code location being tagged.  At runtime, the special section is treated as
+ * an array of these.
+ */
+struct codetag {
+	unsigned int flags; /* used in later patches */
+	unsigned int lineno;
+	const char *modname;
+	const char *function;
+	const char *filename;
+} __aligned(8);
+
+union codetag_ref {
+	struct codetag *ct;
+};
+
+struct codetag_range {
+	struct codetag *start;
+	struct codetag *stop;
+};
+
+struct codetag_module {
+	struct module *mod;
+	struct codetag_range range;
+};
+
+struct codetag_type_desc {
+	const char *section;
+	size_t tag_size;
+};
+
+struct codetag_iterator {
+	struct codetag_type *cttype;
+	struct codetag_module *cmod;
+	unsigned long mod_id;
+	struct codetag *ct;
+};
+
+#define CODE_TAG_INIT {					\
+	.modname	= KBUILD_MODNAME,		\
+	.function	= __func__,			\
+	.filename	= __FILE__,			\
+	.lineno		= __LINE__,			\
+	.flags		= 0,				\
+}
+
+void codetag_lock_module_list(struct codetag_type *cttype, bool lock);
+struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype);
+struct codetag *codetag_next_ct(struct codetag_iterator *iter);
+
+void codetag_to_text(struct seq_buf *out, struct codetag *ct);
+
+struct codetag_type *
+codetag_register_type(const struct codetag_type_desc *desc);
+
+#endif /* _LINUX_CODETAG_H */
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index bcbe60d6c80c..22bc1eff7f8f 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -969,6 +969,10 @@ config DEBUG_STACKOVERFLOW
 
 	  If in doubt, say "N".
 
+config CODE_TAGGING
+	bool
+	select KALLSYMS
+
 source "lib/Kconfig.kasan"
 source "lib/Kconfig.kfence"
 
diff --git a/lib/Makefile b/lib/Makefile
index cc7762748708..574d7716e640 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -227,6 +227,7 @@ obj-$(CONFIG_OF_RECONFIG_NOTIFIER_ERROR_INJECT) += \
 	of-reconfig-notifier-error-inject.o
 obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
 
+obj-$(CONFIG_CODE_TAGGING) += codetag.o
 lib-$(CONFIG_GENERIC_BUG) += bug.o
 
 obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
diff --git a/lib/codetag.c b/lib/codetag.c
new file mode 100644
index 000000000000..7708f8388e55
--- /dev/null
+++ b/lib/codetag.c
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/codetag.h>
+#include <linux/idr.h>
+#include <linux/kallsyms.h>
+#include <linux/module.h>
+#include <linux/seq_buf.h>
+#include <linux/slab.h>
+
+struct codetag_type {
+	struct list_head link;
+	unsigned int count;
+	struct idr mod_idr;
+	struct rw_semaphore mod_lock; /* protects mod_idr */
+	struct codetag_type_desc desc;
+};
+
+static DEFINE_MUTEX(codetag_lock);
+static LIST_HEAD(codetag_types);
+
+void codetag_lock_module_list(struct codetag_type *cttype, bool lock)
+{
+	if (lock)
+		down_read(&cttype->mod_lock);
+	else
+		up_read(&cttype->mod_lock);
+}
+
+struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype)
+{
+	struct codetag_iterator iter = {
+		.cttype = cttype,
+		.cmod = NULL,
+		.mod_id = 0,
+		.ct = NULL,
+	};
+
+	return iter;
+}
+
+static inline struct codetag *get_first_module_ct(struct codetag_module *cmod)
+{
+	return cmod->range.start < cmod->range.stop ? cmod->range.start : NULL;
+}
+
+static inline
+struct codetag *get_next_module_ct(struct codetag_iterator *iter)
+{
+	struct codetag *res = (struct codetag *)
+			((char *)iter->ct + iter->cttype->desc.tag_size);
+
+	return res < iter->cmod->range.stop ? res : NULL;
+}
+
+struct codetag *codetag_next_ct(struct codetag_iterator *iter)
+{
+	struct codetag_type *cttype = iter->cttype;
+	struct codetag_module *cmod;
+	struct codetag *ct;
+
+	lockdep_assert_held(&cttype->mod_lock);
+
+	if (unlikely(idr_is_empty(&cttype->mod_idr)))
+		return NULL;
+
+	ct = NULL;
+	while (true) {
+		cmod = idr_find(&cttype->mod_idr, iter->mod_id);
+
+		/* If module was removed move to the next one */
+		if (!cmod)
+			cmod = idr_get_next_ul(&cttype->mod_idr,
+					       &iter->mod_id);
+
+		/* Exit if no more modules */
+		if (!cmod)
+			break;
+
+		if (cmod != iter->cmod) {
+			iter->cmod = cmod;
+			ct = get_first_module_ct(cmod);
+		} else
+			ct = get_next_module_ct(iter);
+
+		if (ct)
+			break;
+
+		iter->mod_id++;
+	}
+
+	iter->ct = ct;
+	return ct;
+}
+
+void codetag_to_text(struct seq_buf *out, struct codetag *ct)
+{
+	seq_buf_printf(out, "%s:%u module:%s func:%s",
+		       ct->filename, ct->lineno,
+		       ct->modname, ct->function);
+}
+
+static inline size_t range_size(const struct codetag_type *cttype,
+				const struct codetag_range *range)
+{
+	return ((char *)range->stop - (char *)range->start) /
+			cttype->desc.tag_size;
+}
+
+static void *get_symbol(struct module *mod, const char *prefix, const char *name)
+{
+	char buf[64];
+	int res;
+
+	res = snprintf(buf, sizeof(buf), "%s%s", prefix, name);
+	if (WARN_ON(res < 1 || res > sizeof(buf)))
+		return NULL;
+
+	return mod ?
+		(void *)find_kallsyms_symbol_value(mod, buf) :
+		(void *)kallsyms_lookup_name(buf);
+}
+
+static struct codetag_range get_section_range(struct module *mod,
+					      const char *section)
+{
+	return (struct codetag_range) {
+		get_symbol(mod, "__start_", section),
+		get_symbol(mod, "__stop_", section),
+	};
+}
+
+static int codetag_module_init(struct codetag_type *cttype, struct module *mod)
+{
+	struct codetag_range range;
+	struct codetag_module *cmod;
+	int err;
+
+	range = get_section_range(mod, cttype->desc.section);
+	if (!range.start || !range.stop) {
+		pr_warn("Failed to load code tags of type %s from the module %s\n",
+			cttype->desc.section,
+			mod ? mod->name : "(built-in)");
+		return -EINVAL;
+	}
+
+	/* Ignore empty ranges */
+	if (range.start == range.stop)
+		return 0;
+
+	BUG_ON(range.start > range.stop);
+
+	cmod = kmalloc(sizeof(*cmod), GFP_KERNEL);
+	if (unlikely(!cmod))
+		return -ENOMEM;
+
+	cmod->mod = mod;
+	cmod->range = range;
+
+	down_write(&cttype->mod_lock);
+	err = idr_alloc(&cttype->mod_idr, cmod, 0, 0, GFP_KERNEL);
+	if (err >= 0)
+		cttype->count += range_size(cttype, &range);
+	up_write(&cttype->mod_lock);
+
+	if (err < 0) {
+		kfree(cmod);
+		return err;
+	}
+
+	return 0;
+}
+
+struct codetag_type *
+codetag_register_type(const struct codetag_type_desc *desc)
+{
+	struct codetag_type *cttype;
+	int err;
+
+	BUG_ON(desc->tag_size <= 0);
+
+	cttype = kzalloc(sizeof(*cttype), GFP_KERNEL);
+	if (unlikely(!cttype))
+		return ERR_PTR(-ENOMEM);
+
+	cttype->desc = *desc;
+	idr_init(&cttype->mod_idr);
+	init_rwsem(&cttype->mod_lock);
+
+	err = codetag_module_init(cttype, NULL);
+	if (unlikely(err)) {
+		kfree(cttype);
+		return ERR_PTR(err);
+	}
+
+	mutex_lock(&codetag_lock);
+	list_add_tail(&cttype->link, &codetag_types);
+	mutex_unlock(&codetag_lock);
+
+	return cttype;
+}
-- 
2.37.2.672.g94769d06f0-goog


  parent reply	other threads:[~2022-08-30 21:50 UTC|newest]

Thread overview: 138+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-30 21:48 [RFC PATCH 00/30] Code tagging framework and applications Suren Baghdasaryan
2022-08-30 21:48 ` [RFC PATCH 01/30] kernel/module: move find_kallsyms_symbol_value declaration Suren Baghdasaryan
2022-08-30 21:48 ` [RFC PATCH 02/30] lib/string_helpers: Drop space in string_get_size's output Suren Baghdasaryan
2022-08-30 21:48 ` [RFC PATCH 03/30] Lazy percpu counters Suren Baghdasaryan
2022-08-31 10:02   ` Mel Gorman
2022-08-31 15:37     ` Suren Baghdasaryan
2022-08-31 16:20     ` Kent Overstreet
2022-09-01  6:51   ` Peter Zijlstra
2022-09-01 14:32     ` Kent Overstreet
2022-09-01 14:48       ` Steven Rostedt
2022-09-01 15:43         ` Kent Overstreet
2022-09-01 18:59       ` Peter Zijlstra
2022-08-30 21:48 ` [RFC PATCH 04/30] scripts/kallysms: Always include __start and __stop symbols Suren Baghdasaryan
2022-08-30 21:48 ` Suren Baghdasaryan [this message]
2022-08-30 21:48 ` [RFC PATCH 06/30] lib: code tagging module support Suren Baghdasaryan
2022-08-30 21:48 ` [RFC PATCH 07/30] lib: add support for allocation tagging Suren Baghdasaryan
2022-08-30 21:48 ` [RFC PATCH 08/30] lib: introduce page " Suren Baghdasaryan
2022-08-30 21:48 ` [RFC PATCH 09/30] change alloc_pages name in dma_map_ops to avoid name conflicts Suren Baghdasaryan
2022-08-30 21:48 ` [RFC PATCH 10/30] mm: enable page allocation tagging for __get_free_pages and alloc_pages Suren Baghdasaryan
2022-08-31 10:11   ` Mel Gorman
2022-08-31 15:45     ` Suren Baghdasaryan
2022-08-31 15:52       ` Suren Baghdasaryan
2022-08-31 17:46     ` Kent Overstreet
2022-09-01  1:07       ` Suren Baghdasaryan
2022-09-01  7:41       ` Peter Zijlstra
2022-08-30 21:49 ` [RFC PATCH 11/30] mm: introduce slabobj_ext to support slab object extensions Suren Baghdasaryan
2022-09-01 23:35   ` Roman Gushchin
2022-09-02  0:23     ` Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 12/30] mm: introduce __GFP_NO_OBJ_EXT flag to selectively prevent slabobj_ext creation Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 13/30] mm/slab: introduce SLAB_NO_OBJ_EXT to avoid obj_ext creation Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 14/30] mm: prevent slabobj_ext allocations for slabobj_ext and kmem_cache objects Suren Baghdasaryan
2022-09-01 23:40   ` Roman Gushchin
2022-09-02  0:24     ` Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 15/30] lib: introduce slab allocation tagging Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 16/30] mm: enable slab allocation tagging for kmalloc and friends Suren Baghdasaryan
2022-09-01 23:50   ` Roman Gushchin
2022-08-30 21:49 ` [RFC PATCH 17/30] lib/string.c: strsep_no_empty() Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 18/30] codetag: add codetag query helper functions Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 19/30] move stack capture functionality into a separate function for reuse Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 20/30] lib: introduce support for storing code tag context Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 21/30] lib: implement context capture support for page and slab allocators Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 22/30] Code tagging based fault injection Suren Baghdasaryan
2022-08-31  1:51   ` Randy Dunlap
2022-08-31 15:56     ` Suren Baghdasaryan
2022-08-31 10:37   ` Dmitry Vyukov
2022-08-31 15:51     ` Suren Baghdasaryan
2022-08-31 17:30     ` Kent Overstreet
2022-09-01  8:43       ` Dmitry Vyukov
2022-08-30 21:49 ` [RFC PATCH 23/30] timekeeping: Add a missing include Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 24/30] wait: Clean up waitqueue_entry initialization Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 25/30] lib/time_stats: New library for statistics on events Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 26/30] bcache: Convert to lib/time_stats Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 27/30] Code tagging based latency tracking Suren Baghdasaryan
2022-08-31  1:53   ` Randy Dunlap
2022-08-31 15:55     ` Suren Baghdasaryan
2022-09-01  7:11   ` Peter Zijlstra
2022-09-01 14:43     ` Kent Overstreet
2022-09-01 21:38   ` Steven Rostedt
2022-09-01 21:46     ` Steven Rostedt
2022-09-01 21:54     ` Kent Overstreet
2022-09-01 22:34       ` Steven Rostedt
2022-09-01 22:55         ` Kent Overstreet
2022-09-02  0:23           ` Steven Rostedt
2022-09-02  1:35             ` Kent Overstreet
2022-09-02  1:59               ` Steven Rostedt
2022-08-30 21:49 ` [RFC PATCH 28/30] Improved symbolic error names Suren Baghdasaryan
2022-09-01 23:19   ` Joe Perches
2022-09-01 23:26     ` Kent Overstreet
2022-08-30 21:49 ` [RFC PATCH 29/30] dyndbg: Convert to code tagging Suren Baghdasaryan
2022-08-30 21:49 ` [RFC PATCH 30/30] MAINTAINERS: Add entries for code tagging & related Suren Baghdasaryan
2022-08-31  7:38 ` [RFC PATCH 00/30] Code tagging framework and applications Peter Zijlstra
2022-08-31  8:42   ` Kent Overstreet
2022-08-31 10:19     ` Mel Gorman
2022-08-31 10:47       ` Michal Hocko
2022-08-31 15:28         ` Suren Baghdasaryan
2022-08-31 16:48           ` Suren Baghdasaryan
2022-08-31 19:01         ` Kent Overstreet
2022-08-31 20:56           ` Yosry Ahmed
2022-08-31 21:38             ` Suren Baghdasaryan
2022-09-01 22:27             ` Roman Gushchin
2022-09-01 22:37               ` Kent Overstreet
2022-09-01 22:53                 ` Roman Gushchin
2022-09-01 23:36                   ` Suren Baghdasaryan
2022-09-02  0:17                   ` Kent Overstreet
2022-09-02  1:04                     ` Roman Gushchin
2022-09-02  1:16                       ` Kent Overstreet
2022-09-02 12:02                       ` Jens Axboe
2022-09-02 19:48                         ` Kent Overstreet
2022-09-02 19:53                           ` Jens Axboe
2022-09-02 20:05                             ` Kent Overstreet
2022-09-02 20:23                               ` Jens Axboe
2022-09-01  7:18           ` Michal Hocko
2022-09-01 15:33             ` Suren Baghdasaryan
2022-09-01 19:15               ` Michal Hocko
2022-09-01 19:39                 ` Suren Baghdasaryan
2022-09-01 20:15                   ` Kent Overstreet
2022-09-05  8:49                     ` Michal Hocko
2022-09-05 23:46                       ` Kent Overstreet
2022-09-06  7:23                         ` Michal Hocko
2022-09-06 18:20                           ` Kent Overstreet
2022-09-07 11:00                             ` Michal Hocko
2022-09-07 13:04                               ` Kent Overstreet
2022-09-07 13:45                                 ` Steven Rostedt
2022-09-08  6:35                                   ` Kent Overstreet
2022-09-08  6:49                                     ` Suren Baghdasaryan
2022-09-08  7:07                                       ` Kent Overstreet
2022-09-08  7:12                                     ` Michal Hocko
2022-09-08  7:29                                       ` Kent Overstreet
2022-09-08  7:47                                         ` Michal Hocko
2022-09-05  1:32                 ` Suren Baghdasaryan
2022-09-05  8:12                   ` Michal Hocko
2022-09-05  8:58                     ` Marco Elver
2022-09-05 18:07                       ` Suren Baghdasaryan
2022-09-05 18:03                     ` Suren Baghdasaryan
2022-09-06  8:01                       ` Michal Hocko
2022-09-06 15:35                         ` Suren Baghdasaryan
2022-09-05 15:07                   ` Steven Rostedt
2022-09-05 18:08                     ` Suren Baghdasaryan
2022-09-05 20:42                       ` Kent Overstreet
2022-09-05 22:16                         ` Steven Rostedt
2022-09-05 23:50                           ` Kent Overstreet
2022-09-01  8:05           ` David Hildenbrand
2022-09-01 14:23             ` Kent Overstreet
2022-09-01 15:07               ` David Hildenbrand
2022-09-01 15:39                 ` Suren Baghdasaryan
2022-09-01 15:48                 ` Kent Overstreet
2022-08-31 15:59       ` Kent Overstreet
2022-09-01  7:05         ` Peter Zijlstra
2022-09-01  7:36           ` Daniel Bristot de Oliveira
2022-09-01  7:42           ` Peter Zijlstra
2022-09-01 11:05         ` Mel Gorman
2022-09-01 16:31           ` Kent Overstreet
2022-09-01  7:00       ` Peter Zijlstra
2022-09-01 14:29         ` Kent Overstreet
2022-09-05 18:44       ` Nadav Amit
2022-09-05 19:16         ` Steven Rostedt
2022-09-01  4:52 ` Oscar Salvador
2022-09-01  5:05   ` Suren Baghdasaryan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox