+ init-remove-strlcat-and-sprintf-from-do_one_initcall.patch added to mm-nonmm-unstable branch

+ init-remove-strlcat-and-sprintf-from-do_one_initcall.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: init: remove strlcat() and sprintf() from do_one_initcall()
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     init-remove-strlcat-and-sprintf-from-do_one_initcall.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/init-remove-strlcat-and-sprintf-from-do_one_initcall.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Thorsten Blum <blum@kernel.org>
Subject: init: remove strlcat() and sprintf() from do_one_initcall()
Date: Sat, 14 Nov 2026 12:05:31 +0100

In preparation for removing strlcat() from the kernel [1], format the
warning directly in WARN().  This also removes the temporary 64-byte
buffer and the sprintf() call while preserving the warning text.

Link: https://lore.kernel.org/20261114110531.26138-2-blum@kernel.org
Link: https://github.com/KSPP/linux/issues/370 [1]
Signed-off-by: Thorsten Blum <blum@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Sang-Heon Jeon <ekffu200098@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Wilson Felipe Pereira <wfelipe@google.com>

 init/main.c |   21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

--- a/init/main.c~init-remove-strlcat-and-sprintf-from-do_one_initcall
+++ a/init/main.c
@@ -1409,7 +1409,8 @@ static inline void do_trace_initcall_lev
 int __init_or_module do_one_initcall(initcall_t fn)
 {
 	int count = preempt_count();
-	char msgbuf[64];
+	bool preempt_imbalanced;
+	bool irqs_left_disabled;
 	int ret;
 
 	if (initcall_blacklisted(fn))
@@ -1419,17 +1420,17 @@ int __init_or_module do_one_initcall(ini
 	ret = fn();
 	do_trace_initcall_finish(fn, ret);
 
-	msgbuf[0] = 0;
-
-	if (preempt_count() != count) {
-		sprintf(msgbuf, "preemption imbalance ");
+	preempt_imbalanced = preempt_count() != count;
+	if (preempt_imbalanced)
 		preempt_count_set(count);
-	}
-	if (irqs_disabled()) {
-		strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
+
+	irqs_left_disabled = irqs_disabled();
+	if (irqs_left_disabled)
 		local_irq_enable();
-	}
-	WARN(msgbuf[0], "initcall %pS returned with %s\n", fn, msgbuf);
+
+	WARN(preempt_imbalanced || irqs_left_disabled, "initcall %pS returned with %s%s\n", fn,
+	     preempt_imbalanced ? "preemption imbalance " : "",
+	     irqs_left_disabled ? "disabled interrupts " : "");
 
 	add_latent_entropy();
 	return ret;
_

Patches currently in -mm which might be from blum@kernel.org are

init-reject-bare-rodata-parameter-before-architecture-parsing.patch
init-use-strscpy-in-do_initcalls.patch
init-use-kmalloc-in-do_initcalls.patch
init-remove-strlcat-and-sprintf-from-do_one_initcall.patch