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 24/28] dyndbg: make site pointer and checks on it optional (not quite)
Date: Tue, 11 May 2021 12:50:53 -0600 [thread overview]
Message-ID: <20210511185057.3815777-25-jim.cromie@gmail.com> (raw)
In-Reply-To: <20210511185057.3815777-1-jim.cromie@gmail.com>
Wrap declaration and uses of _ddebug.site pointer in ifdefs.
Mostly, this eliminates all the WARN_ONs in ddebug_site_get(),
which seem to be mostly proven (they were BUG_ONs).
This adds macro indirection around ifdef SITE_CHK; adding SITE_INIT_
to adjust the .site initializations, and SITE_COND, which abstracts a
logic test used by is_dyndbg_header_pair(i,s).
TODO: breaks when !defined SITE_CHK - the header, being just a struct
_ddebug, also lost the .site member. Need to specialize the header
struct, then unionize it back in.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
include/linux/dynamic_debug.h | 20 ++++++++++++++++----
lib/dynamic_debug.c | 13 ++++++++++---
2 files changed, 26 insertions(+), 7 deletions(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 06ae1d8d8c10..46901b5348ee 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -6,6 +6,18 @@
#include <linux/jump_label.h>
#endif
+#define SITE_CHK /* include .site pointer and checks on it */
+
+#ifdef SITE_CHK
+#define SITE_CHK_(...) __VA_ARGS__
+#define SITE_COND(_i, _s) (_s == _i->site)
+#define SITE_INIT_(_name) .site = &_name,
+#else
+#define SITE_CHK_(...)
+#define SITE_COND(_i, _s) (true)
+#define SITE_INIT_(name)
+#endif
+
/*
* A pair of these structs are created in 2 special ELF sections
* (__dyndbg, __dyndbg_sites) for every dynamic debug callsite.
@@ -25,7 +37,7 @@ struct _ddebug_site {
} __aligned(8);
struct _ddebug {
- struct _ddebug_site *site;
+ SITE_CHK_(struct _ddebug_site *site;)
/* format is always needed, lineno shares word with flags */
const char *format;
const unsigned lineno:18;
@@ -106,7 +118,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
}; \
static struct _ddebug __aligned(8) \
__section("__dyndbg") name = { \
- .site = &name##_site, \
+ SITE_INIT_(name##_site) \
.format = (fmt), \
.lineno = __LINE__, \
.flags = _DPRINTK_FLAGS_DEFAULT, \
@@ -138,13 +150,13 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
__weak struct _ddebug __used __aligned(8) \
__section(".gnu.linkonce.dyndbg") \
_LINKONCE_dyndbg_header = { \
- .site = &_LINKONCE_dyndbg_site_header, \
+ SITE_INIT_(_LINKONCE_dyndbg_site_header) \
.format = KBUILD_MODNAME \
}
/* The header initializations as a distinguishing predicate */
#define is_dyndbg_header_pair(iter, sitep) \
- (sitep == iter->site \
+ (SITE_COND(iter, sitep) \
&& (!iter->lineno) \
&& (iter->format == sitep->modname) \
&& (sitep->modname == sitep->function) \
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index b83187e72ee0..9551c0d406b6 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -151,7 +151,7 @@ static struct _ddebug_site *ddebug_site_get(struct _ddebug *dp)
struct _ddebug *dh = dp - (dp->_index);
WARN_ON(!is_dyndbg_header_pair(dh, dh->site));
-
+#ifdef SITE_CHK
if (dp >= __start___dyndbg && dp < __stop___dyndbg) {
v5pr_info("get: %s is builtin: %d %s:%s:%d\n",
@@ -177,6 +177,9 @@ static struct _ddebug_site *ddebug_site_get(struct _ddebug *dp)
WARN_ON(&dh->site[dp->_index] != dp->site);
return dp->site;
+#else
+ return &dh->site[dp->_index];
+#endif
}
static inline void ddebug_site_put(struct _ddebug *dp)
{
@@ -241,6 +244,7 @@ static void ddebug_alter_site(struct _ddebug *dp,
} else if (modifiers->flags & _DPRINTK_FLAGS_PRINT)
static_branch_enable(&dp->key.dd_key_true);
#endif
+#ifdef SITE_CHK
/* delete site info for this callsite */
if (modifiers->flags & _DPRINTK_FLAGS_DELETE_SITE) {
if (dp->site) {
@@ -249,6 +253,7 @@ static void ddebug_alter_site(struct _ddebug *dp,
dp->site = NULL;
}
}
+#endif
}
/*
@@ -1073,7 +1078,9 @@ static int __ddebug_add_module(struct _ddebug *tab, struct _ddebug_site *sites,
v3pr_info(" header: %d %s.%s.%d\n", tab[0]._index, modname,
tab[0].site->function, tab[0].lineno);
- WARN_ON(tab[0].site != &sites[0]);
+
+ SITE_CHK_(BUG_ON(tab[0].site != &sites[0]));
+
if (numdbgs <= 1) {
v3pr_info(" skip header %s\n", modname);
return 0;
@@ -1251,7 +1258,7 @@ static int __init dynamic_debug_init(void)
for (i = 0; iter < __stop___dyndbg; iter++, site++, i++) {
- WARN_ON(site != iter->site);
+ SITE_CHK_(WARN_ON(site != iter->site));
if (strcmp(modname, site->modname)) {
modct++;
--
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 ` Jim Cromie [this message]
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 ` [RFC PATCH v5 28/28] dyndbg: RFC drop _ddebug.site pointer Jim Cromie
2021-05-12 22:08 ` Fwd: [RFC PATCH v5 00/28] dynamic debug diet plan jim.cromie
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