+ mm-mmap_lock-fix-disabling-preemption-directly.patch added to -mm tree

+ mm-mmap_lock-fix-disabling-preemption-directly.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: mmap_lock: fix disabling preemption directly
has been added to the -mm tree.  Its filename is
     mm-mmap_lock-fix-disabling-preemption-directly.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-mmap_lock-fix-disabling-preemption-directly.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-mmap_lock-fix-disabling-preemption-directly.patch

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------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: mmap_lock: fix disabling preemption directly

The commit 832b50725373 ("mm: mmap_lock: use local locks instead of
disabling preemption") fix a bug by using local locks.  But commit
d01079f3d0c0 ("mm/mmap_lock: remove dead code for !CONFIG_TRACING
configurations") changes those lines to original version.  I guess it is
introduced by the conflicts fixing on merging.

Link: https://lkml.kernel.org/r/20210720074228.76342-1-songmuchun@bytedance.com
Fixes: d01079f3d0c0 ("mm/mmap_lock: remove dead code for !CONFIG_TRACING configurations")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mmap_lock.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/mmap_lock.c~mm-mmap_lock-fix-disabling-preemption-directly
+++ a/mm/mmap_lock.c
@@ -156,14 +156,14 @@ static inline void put_memcg_path_buf(vo
 #define TRACE_MMAP_LOCK_EVENT(type, mm, ...)                                   \
 	do {                                                                   \
 		const char *memcg_path;                                        \
-		preempt_disable();                                             \
+		local_lock(&memcg_paths.lock);                                 \
 		memcg_path = get_mm_memcg_path(mm);                            \
 		trace_mmap_lock_##type(mm,                                     \
 				       memcg_path != NULL ? memcg_path : "",   \
 				       ##__VA_ARGS__);                         \
 		if (likely(memcg_path != NULL))                                \
 			put_memcg_path_buf();                                  \
-		preempt_enable();                                              \
+		local_unlock(&memcg_paths.lock);                               \
 	} while (0)
 
 #else /* !CONFIG_MEMCG */
_

Patches currently in -mm which might be from songmuchun@bytedance.com are

mm-mmap_lock-fix-disabling-preemption-directly.patch