The patch titled
Subject: mm/madvise: employ mmget_still_valid() for write lock
has been added to the -mm tree. Its filename is
mm-madvise-employ-mmget_still_valid-for-write-lock.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-madvise-employ-mmget_still_valid-for-write-lock.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-madvise-employ-mmget_still_valid-for-write-lock.patch
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------------------------------------------------------
From: Oleksandr Natalenko <oleksandr@xxxxxxxxxx>
Subject: mm/madvise: employ mmget_still_valid() for write lock
Do the very same trick as we already do since 04f5866e41fb. KSM hints
will require locking mmap_sem for write since they modify vm_flags, so for
remote KSM hinting this additional check is needed.
Link: http://lkml.kernel.org/r/20200302193630.68771-7-minchan@xxxxxxxxxx
Signed-off-by: Oleksandr Natalenko <oleksandr@xxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
Reviewed-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Cc: Brian Geffon <bgeffon@xxxxxxxxxx>
Cc: Christian Brauner <christian@xxxxxxxxxx>
Cc: Daniel Colascione <dancol@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: John Dias <joaodias@xxxxxxxxxx>
Cc: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Sandeep Patil <sspatil@xxxxxxxxxx>
Cc: SeongJae Park <sj38.park@xxxxxxxxx>
Cc: SeongJae Park <sjpark@xxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Sonny Rao <sonnyrao@xxxxxxxxxx>
Cc: Tim Murray <timmurray@xxxxxxxxxx>
Cc: <linux-man@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/madvise.c | 3 +++
1 file changed, 3 insertions(+)
--- a/mm/madvise.c~mm-madvise-employ-mmget_still_valid-for-write-lock
+++ a/mm/madvise.c
@@ -1118,6 +1118,8 @@ int do_madvise(struct task_struct *targe
if (write) {
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
+ if (current->mm != mm && !mmget_still_valid(mm))
+ goto skip_mm;
} else {
down_read(&mm->mmap_sem);
}
@@ -1169,6 +1171,7 @@ int do_madvise(struct task_struct *targe
}
out:
blk_finish_plug(&plug);
+skip_mm:
if (write)
up_write(&mm->mmap_sem);
else
_
Patches currently in -mm which might be from oleksandr@xxxxxxxxxx are
mm-madvise-employ-mmget_still_valid-for-write-lock.patch
mm-madvise-allow-ksm-hints-for-remote-api.patch
