The patch titled
Subject: prctl: add comment about mmap_sem and arg_lock
has been removed from the -mm tree. Its filename was
mm-introduce-arg_lock-to-protect-arg_startend-and-env_startend-in-mm_struct-fix.patch
This patch was dropped because it was folded into mm-introduce-arg_lock-to-protect-arg_startend-and-env_startend-in-mm_struct.patch
------------------------------------------------------
From: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Subject: prctl: add comment about mmap_sem and arg_lock
add comment to elaborate why mmap_sem for is used by prctl
Link: http://lkml.kernel.org/r/1524077799-80690-1-git-send-email-yang.shi@xxxxxxxxxxxxxxxxx
Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mateusz Guzik <mguzik@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/sys.c | 4 ++++
1 file changed, 4 insertions(+)
diff -puN kernel/sys.c~mm-introduce-arg_lock-to-protect-arg_startend-and-env_startend-in-mm_struct-fix kernel/sys.c
--- a/kernel/sys.c~mm-introduce-arg_lock-to-protect-arg_startend-and-env_startend-in-mm_struct-fix
+++ a/kernel/sys.c
@@ -2018,6 +2018,10 @@ static int prctl_set_mm_map(int opt, con
return error;
}
+ /*
+ * arg_lock protects concurent updates but we still need mmap_sem for
+ * read to exclude races with sys_brk.
+ */
down_read(&mm->mmap_sem);
/*
_
Patches currently in -mm which might be from yang.shi@xxxxxxxxxxxxxxxxx are
mm-introduce-arg_lock-to-protect-arg_startend-and-env_startend-in-mm_struct.patch
mm-shmem-make-statst_blksize-return-huge-page-size-if-thp-is-on.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
