+ kmsan-rework-kmsan_in_runtime-handling-in-kmsan_report.patch added to mm-new branch

+ kmsan-rework-kmsan_in_runtime-handling-in-kmsan_report.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: kmsan: rework kmsan_in_runtime() handling in kmsan_report()
has been added to the -mm mm-new branch.  Its filename is
     kmsan-rework-kmsan_in_runtime-handling-in-kmsan_report.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kmsan-rework-kmsan_in_runtime-handling-in-kmsan_report.patch

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

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
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fixup patches in mm-new.

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branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Alexander Potapenko <glider@google.com>
Subject: kmsan: rework kmsan_in_runtime() handling in kmsan_report()
Date: Wed, 7 May 2025 18:00:12 +0200

kmsan_report() calls used to require entering/leaving the runtime around
them.  To simplify the things, drop this requirement and move calls to
kmsan_enter_runtime()/kmsan_leave_runtime() into kmsan_report().

Link: https://lkml.kernel.org/r/20250507160012.3311104-5-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/kmsan/core.c            |    8 --------
 mm/kmsan/instrumentation.c |    4 ----
 mm/kmsan/report.c          |    6 +++---
 3 files changed, 3 insertions(+), 15 deletions(-)

--- a/mm/kmsan/core.c~kmsan-rework-kmsan_in_runtime-handling-in-kmsan_report
+++ a/mm/kmsan/core.c
@@ -274,11 +274,9 @@ void kmsan_internal_check_memory(void *a
 			 * bytes before, report them.
 			 */
 			if (cur_origin) {
-				kmsan_enter_runtime();
 				kmsan_report(cur_origin, addr, size,
 					     cur_off_start, pos - 1, user_addr,
 					     reason);
-				kmsan_leave_runtime();
 			}
 			cur_origin = 0;
 			cur_off_start = -1;
@@ -292,11 +290,9 @@ void kmsan_internal_check_memory(void *a
 				 * poisoned bytes before, report them.
 				 */
 				if (cur_origin) {
-					kmsan_enter_runtime();
 					kmsan_report(cur_origin, addr, size,
 						     cur_off_start, pos + i - 1,
 						     user_addr, reason);
-					kmsan_leave_runtime();
 				}
 				cur_origin = 0;
 				cur_off_start = -1;
@@ -312,11 +308,9 @@ void kmsan_internal_check_memory(void *a
 			 */
 			if (cur_origin != new_origin) {
 				if (cur_origin) {
-					kmsan_enter_runtime();
 					kmsan_report(cur_origin, addr, size,
 						     cur_off_start, pos + i - 1,
 						     user_addr, reason);
-					kmsan_leave_runtime();
 				}
 				cur_origin = new_origin;
 				cur_off_start = pos + i;
@@ -326,10 +320,8 @@ void kmsan_internal_check_memory(void *a
 	}
 	KMSAN_WARN_ON(pos != size);
 	if (cur_origin) {
-		kmsan_enter_runtime();
 		kmsan_report(cur_origin, addr, size, cur_off_start, pos - 1,
 			     user_addr, reason);
-		kmsan_leave_runtime();
 	}
 }
 
--- a/mm/kmsan/instrumentation.c~kmsan-rework-kmsan_in_runtime-handling-in-kmsan_report
+++ a/mm/kmsan/instrumentation.c
@@ -312,13 +312,9 @@ EXPORT_SYMBOL(__msan_unpoison_alloca);
 void __msan_warning(u32 origin);
 void __msan_warning(u32 origin)
 {
-	if (!kmsan_enabled || kmsan_in_runtime())
-		return;
-	kmsan_enter_runtime();
 	kmsan_report(origin, /*address*/ NULL, /*size*/ 0,
 		     /*off_first*/ 0, /*off_last*/ 0, /*user_addr*/ NULL,
 		     REASON_ANY);
-	kmsan_leave_runtime();
 }
 EXPORT_SYMBOL(__msan_warning);
 
--- a/mm/kmsan/report.c~kmsan-rework-kmsan_in_runtime-handling-in-kmsan_report
+++ a/mm/kmsan/report.c
@@ -157,14 +157,14 @@ void kmsan_report(depot_stack_handle_t o
 	unsigned long ua_flags;
 	bool is_uaf;
 
-	if (!kmsan_enabled)
+	if (!kmsan_enabled || kmsan_in_runtime())
 		return;
 	if (current->kmsan_ctx.depth)
 		return;
 	if (!origin)
 		return;
 
-	kmsan_disable_current();
+	kmsan_enter_runtime();
 	ua_flags = user_access_save();
 	raw_spin_lock(&kmsan_report_lock);
 	pr_err("=====================================================\n");
@@ -217,5 +217,5 @@ void kmsan_report(depot_stack_handle_t o
 	if (panic_on_kmsan)
 		panic("kmsan.panic set ...\n");
 	user_access_restore(ua_flags);
-	kmsan_enable_current();
+	kmsan_leave_runtime();
 }
_

Patches currently in -mm which might be from glider@google.com are

kmsan-apply-clang-format-to-files-mm-kmsan.patch
kmsan-fix-usage-of-kmsan_enter_runtime-in-kmsan_vmap_pages_range_noflush.patch
kmsan-drop-the-declaration-of-kmsan_save_stack.patch
kmsan-enter-the-runtime-around-kmsan_internal_memmove_metadata-call.patch
kmsan-rework-kmsan_in_runtime-handling-in-kmsan_report.patch