The mems_allowed field can be modified by other tasks, so it
isn't safe to access it with alloc_lock unlocked even in the
current process context.
Fixes: 78b132e9bae9 ("mm/mempolicy: remove or narrow the lock on current")
Signed-off-by: Abel Wu <wuyun.abel@xxxxxxxxxxxxx>
---
mm/mempolicy.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index d39b01fd52fe..ae422e44affb 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -855,12 +855,14 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags,
goto out;
}
+ task_lock(current);
ret = mpol_set_nodemask(new, nodes, scratch);
if (ret) {
+ task_unlock(current);
mpol_put(new);
goto out;
}
- task_lock(current);
+
old = current->mempolicy;
current->mempolicy = new;
if (new && new->mode == MPOL_INTERLEAVE)
@@ -1295,7 +1297,9 @@ static long do_mbind(unsigned long start, unsigned long len,
NODEMASK_SCRATCH(scratch);
if (scratch) {
mmap_write_lock(mm);
+ task_lock(current);
err = mpol_set_nodemask(new, nmask, scratch);
+ task_unlock(current);
if (err)
mmap_write_unlock(mm);
} else
--
2.31.1
