mm: expose abnormal new_pte during move_ptes

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When executing move_ptes, the new_pte must be NULL, otherwise it will be
overwritten by the old_pte, and cause the abnormal new_pte to be leaked. 
In order to make this problem to be more explicit, let's add WARN_ON_ONCE
when new_pte is not NULL.

[akpm@linux-foundation.org: s/WARN_ON_ONCE/VM_WARN_ON_ONCE/]
Link: https://lkml.kernel.org/r/20250529155650.4017699-3-pulehui@huaweicloud.com
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

...

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Pu Lehui 2025-05-29 15:56:48 +00:00 • committed by Andrew Morton

parent 2b12d06c37

commit b36b701bbc

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mm/mremap.c

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