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Message-Id: <126e7c2d94255c5d02d53941eca7a01e7ad08df5.1456241060.git.jpoimboe@redhat.com>
Date: Tue, 23 Feb 2016 09:27:40 -0600
From: Josh Poimboeuf <jpoimboe@...hat.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Prarit Bhargava <prarit@...hat.com>,
Chunyu Hu <chuhu@...hat.com>
Subject: [PATCH v2] lib/bug.c: use common WARN helper
The traceoff_on_warning option doesn't have any effect on s390, powerpc,
arm64, parisc, and sh because there are two different types of WARN
implementations:
1) The above mentioned architectures treat WARN() as a special case of a
BUG() exception. They handle warnings in report_bug() in lib/bug.c.
2) All other architectures just call warn_slowpath_*() directly. Their
warnings are handled in warn_slowpath_common() in kernel/panic.c.
Support traceoff_on_warning on all architectures and prevent any future
divergence by using a single common function to emit the warning.
Also remove the '()' from '%pS()', because the parentheses look funky:
[ 45.607629] WARNING: at /root/warn_mod/warn_mod.c:17 .init_dummy+0x20/0x40 [warn_mod]()
Reported-by: Chunyu Hu <chuhu@...hat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
Acked-by: Heiko Carstens <heiko.carstens@...ibm.com>
Acked-and-tested-by: Prarit Bhargava <prarit@...hat.com>
---
v2:
- removed extra blank link in lib/bug.c (Prarit)
- moved warn_args definition to panic.c (Steven)
include/asm-generic/bug.h | 6 ++++++
kernel/panic.c | 41 ++++++++++++++++++++++++++---------------
lib/bug.c | 26 ++------------------------
3 files changed, 34 insertions(+), 39 deletions(-)
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 630dd23..18a230d 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -81,6 +81,12 @@ extern void warn_slowpath_null(const char *file, const int line);
do { printk(arg); __WARN_TAINT(taint); } while (0)
#endif
+/* used internally by panic.c */
+struct warn_args;
+
+void __warn(const char *file, int line, void *caller, unsigned taint,
+ struct pt_regs *regs, struct warn_args *args);
+
#ifndef WARN_ON
#define WARN_ON(condition) ({ \
int __ret_warn_on = !!(condition); \
diff --git a/kernel/panic.c b/kernel/panic.c
index d96469d..fa40085 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -24,6 +24,7 @@
#include <linux/init.h>
#include <linux/nmi.h>
#include <linux/console.h>
+#include <linux/bug.h>
#define PANIC_TIMER_STEP 100
#define PANIC_BLINK_SPD 18
@@ -449,20 +450,25 @@ void oops_exit(void)
kmsg_dump(KMSG_DUMP_OOPS);
}
-#ifdef WANT_WARN_ON_SLOWPATH
-struct slowpath_args {
+struct warn_args {
const char *fmt;
va_list args;
};
-static void warn_slowpath_common(const char *file, int line, void *caller,
- unsigned taint, struct slowpath_args *args)
+void __warn(const char *file, int line, void *caller, unsigned taint,
+ struct pt_regs *regs, struct warn_args *args)
{
disable_trace_on_warning();
pr_warn("------------[ cut here ]------------\n");
- pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS()\n",
- raw_smp_processor_id(), current->pid, file, line, caller);
+
+ if (file)
+ pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n",
+ raw_smp_processor_id(), current->pid, file, line,
+ caller);
+ else
+ pr_warn("WARNING: CPU: %d PID: %d at %pS\n",
+ raw_smp_processor_id(), current->pid, caller);
if (args)
vprintk(args->fmt, args->args);
@@ -479,20 +485,27 @@ static void warn_slowpath_common(const char *file, int line, void *caller,
}
print_modules();
- dump_stack();
+
+ if (regs)
+ show_regs(regs);
+ else
+ dump_stack();
+
print_oops_end_marker();
+
/* Just a warning, don't kill lockdep. */
add_taint(taint, LOCKDEP_STILL_OK);
}
+#ifdef WANT_WARN_ON_SLOWPATH
void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
{
- struct slowpath_args args;
+ struct warn_args args;
args.fmt = fmt;
va_start(args.args, fmt);
- warn_slowpath_common(file, line, __builtin_return_address(0),
- TAINT_WARN, &args);
+ __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL,
+ &args);
va_end(args.args);
}
EXPORT_SYMBOL(warn_slowpath_fmt);
@@ -500,20 +513,18 @@ EXPORT_SYMBOL(warn_slowpath_fmt);
void warn_slowpath_fmt_taint(const char *file, int line,
unsigned taint, const char *fmt, ...)
{
- struct slowpath_args args;
+ struct warn_args args;
args.fmt = fmt;
va_start(args.args, fmt);
- warn_slowpath_common(file, line, __builtin_return_address(0),
- taint, &args);
+ __warn(file, line, __builtin_return_address(0), taint, NULL, &args);
va_end(args.args);
}
EXPORT_SYMBOL(warn_slowpath_fmt_taint);
void warn_slowpath_null(const char *file, int line)
{
- warn_slowpath_common(file, line, __builtin_return_address(0),
- TAINT_WARN, NULL);
+ __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL, NULL);
}
EXPORT_SYMBOL(warn_slowpath_null);
#endif
diff --git a/lib/bug.c b/lib/bug.c
index 6cde380..bc3656e 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -167,30 +167,8 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
if (warning) {
/* this is a WARN_ON rather than BUG/BUG_ON */
- pr_warn("------------[ cut here ]------------\n");
-
- if (file)
- pr_warn("WARNING: at %s:%u\n", file, line);
- else
- pr_warn("WARNING: at %p [verbose debug info unavailable]\n",
- (void *)bugaddr);
-
- if (panic_on_warn) {
- /*
- * This thread may hit another WARN() in the panic path.
- * Resetting this prevents additional WARN() from
- * panicking the system on this thread. Other threads
- * are blocked by the panic_mutex in panic().
- */
- panic_on_warn = 0;
- panic("panic_on_warn set ...\n");
- }
-
- print_modules();
- show_regs(regs);
- print_oops_end_marker();
- /* Just a warning, don't kill lockdep. */
- add_taint(BUG_GET_TAINT(bug), LOCKDEP_STILL_OK);
+ __warn(file, line, (void *)bugaddr, BUG_GET_TAINT(bug), regs,
+ NULL);
return BUG_TRAP_TYPE_WARN;
}
--
2.4.3
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