From: Jim Cromie <jim.cromie@gmail.com>
To: Jason Baron <jbaron@akamai.com>, linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, Jim Cromie <jim.cromie@gmail.com>
Subject: [RFC PATCH v5 28/28] dyndbg: RFC drop _ddebug.site pointer
Date: Tue, 11 May 2021 12:50:57 -0600 [thread overview]
Message-ID: <20210511185057.3815777-29-jim.cromie@gmail.com> (raw)
In-Reply-To: <20210511185057.3815777-1-jim.cromie@gmail.com>
In .h, flip the switch on #define SITE_CHK. This finally removes the
_ddebug.site pointer, and all uses of it. Due to this, the .site
cross-link done by DEFINE_DYNAMIC_DEBUG_METADATA() is lost to the
compiler, so suppress the resulting warnings by adding a "__used" to
the _ddebug_site records initialized there.
In .c, fix a bunch of fallout:
- mostly casts from struct to/from union
- convert a BUG_ON to a WARN,
it happens ~20x per `cat control`, probably headers on loaded modules
- fixup missing _ddebug_header.site,
bad initialization of some sort.
This seems to work, but should be cleaner. RFC
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
include/linux/dynamic_debug.h | 4 ++--
lib/dynamic_debug.c | 25 +++++++++++++++++--------
2 files changed, 19 insertions(+), 10 deletions(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 9ca413985fb2..7f2b255a25ae 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -6,7 +6,7 @@
#include <linux/jump_label.h>
#endif
-#define SITE_CHK /* include .site pointer and checks on it */
+// #define SITE_CHK /* include .site pointer and checks on it */
#ifdef SITE_CHK
#define SITE_CHK_(...) __VA_ARGS__
@@ -135,7 +135,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
const char *fmt, ...);
#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
- static struct _ddebug_site __aligned(8) \
+ static struct _ddebug_site __aligned(8) __used \
__section("__dyndbg_sites") name##_site = { \
.modname = KBUILD_MODNAME, \
.filename = __FILE__, \
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index aa4a476d70ad..db759c998c54 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -148,9 +148,12 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
static struct _ddebug_site *ddebug_site_get(struct _ddebug *dp)
{
- struct _ddebug *dh = dp - (dp->_index);
+ union _ddebug_header *dh = (union _ddebug_header *) (dp - dp->_index);
+
+ if (!is_dyndbg_header_pair(dh, dh->site)) {
+ v3pr_info("get: header fail\n");
+ }
- BUG_ON(!is_dyndbg_header_pair(dh, dh->site));
#ifdef SITE_CHK
if (dp >= __start___dyndbg && dp < __stop___dyndbg) {
@@ -178,7 +181,7 @@ static struct _ddebug_site *ddebug_site_get(struct _ddebug *dp)
return dp->site;
#else
- return &dh->site[dp->_index];
+ return (struct _ddebug_site *) &dh->site[dp->_index];
#endif
}
static inline void ddebug_site_put(struct _ddebug *dp)
@@ -1070,17 +1073,23 @@ static int __ddebug_add_module(struct _ddebug *tab, struct _ddebug_site *sites,
const char *modname)
{
struct ddebug_table *dt;
+ union _ddebug_header *dh = (union _ddebug_header *) &tab[0];
int i;
v3pr_info("add-module: %s.%d sites\n", modname, numdbgs);
- if (numdbgs && is_dyndbg_header_pair(tab, sites)) {
+ if (numdbgs && is_dyndbg_header_pair(dh, sites)) {
- v3pr_info(" header: %d %s.%s.%d\n", tab[0]._index, modname,
- tab[0].site->function, tab[0].lineno);
+ v3pr_info(" header: %d %s.\n", dh->_index, modname);
- SITE_CHK_(BUG_ON(tab[0].site != &sites[0]));
+ SITE_CHK_(BUG_ON(dh->site[0] != &sites[0]));
+ /* for !SITE_CHK, need to set site ptr, fixup missed init! */
+ if (!dh->site) {
+ dh->site = (union _ddebug_site_header *) sites;
+ v3pr_info(" header: %d %s.%s.%d\n", dh->_index, modname,
+ dh->site->function, dh->lineno);
+ }
if (numdbgs <= 1) {
v3pr_info(" skip header %s\n", modname);
return 0;
@@ -1110,7 +1119,7 @@ static int __ddebug_add_module(struct _ddebug *tab, struct _ddebug_site *sites,
for (i = 0; i < numdbgs; i++, base++) {
tab[i]._index = base;
v3pr_info(" %d %d %s.%s.%d\n", i, base, modname,
- tab[i].site->function, tab[i].lineno);
+ sites[i].function, tab[i].lineno);
}
mutex_lock(&ddebug_lock);
--
2.31.1
next prev parent reply other threads:[~2021-05-11 18:52 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210511185057.3815777-1-jim.cromie@gmail.com>
2021-05-11 18:50 ` [RFC PATCH v5 01/28] dyndbg: avoid calling dyndbg_emit_prefix when it has no work Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 02/28] dyndbg: drop uninformative vpr_info Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 03/28] dyndbg: split struct _ddebug's display fields to new _ddebug_site Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 04/28] dyndbg: __init iterate over __dyndbg & __dyndbg_site in parallel Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 05/28] dyndbg: refactor part of ddebug_change to ddebug_match_site Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 06/28] dyndbg: accept null site in ddebug_match_site Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 07/28] dyndbg: hoist ->site out of ddebug_match_site Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 08/28] dyndbg: accept null site in ddebug_change Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 09/28] dyndbg: accept null site in dynamic_emit_prefix Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 10/28] dyndbg: accept null site in ddebug_proc_show Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 11/28] dyndbg: refactor ddebug_alter_site out of ddebug_change Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 12/28] dyndbg: allow deleting site info via control interface Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 13/28] dyndbg+module: expose ddebug_sites to modules Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 14/28] dyndbg: add ddebug_site(_get|_put) abstraction Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 15/28] dyndbg: ddebug_add_module avoid adding empty modules Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 16/28] dyndbg: add _index to struct _ddebug Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 17/28] dyndbg: prevent build bugs via -DNO_DYNAMIC_DEBUG_TABLE Jim Cromie
2021-05-12 14:55 ` Ard Biesheuvel
2021-05-12 18:03 ` jim.cromie
2021-05-11 18:50 ` [RFC PATCH v5 18/28] dyndbg: RFC - DEFINE_DYNAMIC_DEBUG_TABLE Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 19/28] dyndbg: RFC handle __dyndbg* sections in module.lds.h Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 20/28] dyndbg: ddebug_add_module() handle headers Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 21/28] dyndbg: validate ddebug_site_get invariants Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 22/28] dyndbg: fix NULL deref after deleting sites Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 23/28] dyndbg: dont show header records in control Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 24/28] dyndbg: make site pointer and checks on it optional (not quite) Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 25/28] dyndbg: swap WARN_ON for BUG_ON see what 0-day says Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 26/28] dyndbg: fixup protect header when deleting site Jim Cromie
2021-05-11 18:50 ` [RFC PATCH v5 27/28] dyndbg: unionize _ddebug*_headers with struct _ddebug* Jim Cromie
2021-05-11 18:50 ` Jim Cromie [this message]
2021-05-12 22:08 ` Fwd: [RFC PATCH v5 00/28] dynamic debug diet plan jim.cromie
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