Commit 2553b67a authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Linus Torvalds
Browse files

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: default avatarChunyu Hu <chuhu@redhat.com>
Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: default avatarPrarit Bhargava <prarit@redhat.com>
Acked-by: default avatarPrarit Bhargava <prarit@redhat.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4cc7ecb7

include/asm-generic/bug.h

+6 −0
Original line number Diff line number Diff line
@@ -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);				\

kernel/panic.c

+26 −15
Original line number Diff line number Diff line
@@ -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();



	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

lib/bug.c

+2 −24
Original line number Diff line number Diff line
@@ -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;

	}

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