From: Peter Zijlstra <peterz@infradead.org>
Date: Sat, 7 Jun 2025 08:52:28 +0000 (+0200)
Subject: bug: Add report_bug_entry()
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7d2c27a0ec5ecec980b623ded45758918c00b164;p=thirdparty%2Fkernel%2Flinux.git

bug: Add report_bug_entry()

Add a report_bug() variant where the bug_entry is already known. This
is useful when the exception instruction is not instantiated per-site.
But instead has a single instance. In such a case the bug_entry
address might be passed along in a known register or something.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251110115757.575795595@infradead.org
---

diff --git a/include/linux/bug.h b/include/linux/bug.h
index a9948a9f1093b..17a4933c611b0 100644
--- a/include/linux/bug.h
+++ b/include/linux/bug.h
@@ -42,6 +42,7 @@ void bug_get_file_line(struct bug_entry *bug, const char **file,
 struct bug_entry *find_bug(unsigned long bugaddr);
 
 enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs);
+enum bug_trap_type report_bug_entry(struct bug_entry *bug, struct pt_regs *regs);
 
 /* These are defined by the architecture */
 int is_valid_bugaddr(unsigned long addr);
@@ -62,6 +63,13 @@ static inline enum bug_trap_type report_bug(unsigned long bug_addr,
 }
 
 struct bug_entry;
+
+static inline enum bug_trap_type
+report_bug_entry(struct bug_entry *bug, struct pt_regs *regs)
+{
+	return BUG_TRAP_TYPE_BUG;
+}
+
 static inline void bug_get_file_line(struct bug_entry *bug, const char **file,
 				     unsigned int *line)
 {
diff --git a/lib/bug.c b/lib/bug.c
index 8100258a20048..581a66b88c5c0 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -183,18 +183,20 @@ static void __warn_printf(const char *fmt, struct pt_regs *regs)
 	printk("%s", fmt);
 }
 
-static enum bug_trap_type __report_bug(unsigned long bugaddr, struct pt_regs *regs)
+static enum bug_trap_type __report_bug(struct bug_entry *bug, unsigned long bugaddr, struct pt_regs *regs)
 {
 	bool warning, once, done, no_cut, has_args;
 	const char *file, *fmt;
 	unsigned line;
 
-	if (!is_valid_bugaddr(bugaddr))
-		return BUG_TRAP_TYPE_NONE;
+	if (!bug) {
+		if (!is_valid_bugaddr(bugaddr))
+			return BUG_TRAP_TYPE_NONE;
 
-	bug = find_bug(bugaddr);
-	if (!bug)
-		return BUG_TRAP_TYPE_NONE;
+		bug = find_bug(bugaddr);
+		if (!bug)
+			return BUG_TRAP_TYPE_NONE;
+	}
 
 	disable_trace_on_warning();
 
@@ -244,13 +246,25 @@ static enum bug_trap_type __report_bug(unsigned long bugaddr, struct pt_regs *re
 	return BUG_TRAP_TYPE_BUG;
 }
 
+enum bug_trap_type report_bug_entry(struct bug_entry *bug, struct pt_regs *regs)
+{
+	enum bug_trap_type ret;
+	bool rcu = false;
+
+	rcu = warn_rcu_enter();
+	ret = __report_bug(bug, 0, regs);
+	warn_rcu_exit(rcu);
+
+	return ret;
+}
+
 enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
 {
 	enum bug_trap_type ret;
 	bool rcu = false;
 
 	rcu = warn_rcu_enter();
-	ret = __report_bug(bugaddr, regs);
+	ret = __report_bug(NULL, bugaddr, regs);
 	warn_rcu_exit(rcu);
 
 	return ret;