Fix caller information for warn_slowpath_null
Ian Campbell noticed that since "Eliminate thousands of warnings with
gcc 3.2 build" (commit 57adc4d2dbf968fdbe516359688094eef4d46581) all
WARN_ON()'s currently appear to come from warn_slowpath_null(), eg:
WARNING: at kernel/softirq.c:143 warn_slowpath_null+0x1c/0x20()
because now that warn_slowpath_null() is in the call path, the
__builtin_return_address(0) returns that, rather than the place that
caused the warning.
Fix this by splitting up the warn_slowpath_null/fmt cases differently,
using a common helper function, and getting the return address in the
right place. This also happens to avoid the unnecessary stack usage for
the non-stdargs case, and just generally cleans things up.
Make the function name printout use %pS while at it.
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/panic.c b/kernel/panic.c
index 874ecf1..984b3ec 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -340,39 +340,44 @@
}
#ifdef WANT_WARN_ON_SLOWPATH
-void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
-{
+struct slowpath_args {
+ const char *fmt;
va_list args;
- char function[KSYM_SYMBOL_LEN];
- unsigned long caller = (unsigned long)__builtin_return_address(0);
+};
+
+static void warn_slowpath_common(const char *file, int line, void *caller, struct slowpath_args *args)
+{
const char *board;
- sprint_symbol(function, caller);
-
printk(KERN_WARNING "------------[ cut here ]------------\n");
- printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
- line, function);
+ printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
board = dmi_get_system_info(DMI_PRODUCT_NAME);
if (board)
printk(KERN_WARNING "Hardware name: %s\n", board);
- if (*fmt) {
- va_start(args, fmt);
- vprintk(fmt, args);
- va_end(args);
- }
+ if (args)
+ vprintk(args->fmt, args->args);
print_modules();
dump_stack();
print_oops_end_marker();
add_taint(TAINT_WARN);
}
+
+void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
+{
+ struct slowpath_args args;
+
+ args.fmt = fmt;
+ va_start(args.args, fmt);
+ warn_slowpath_common(file, line, __builtin_return_address(0), &args);
+ va_end(args.args);
+}
EXPORT_SYMBOL(warn_slowpath_fmt);
void warn_slowpath_null(const char *file, int line)
{
- static const char *empty = "";
- warn_slowpath_fmt(file, line, empty);
+ warn_slowpath_common(file, line, __builtin_return_address(0), NULL);
}
EXPORT_SYMBOL(warn_slowpath_null);
#endif