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Message-Id: <20221003070722.852051421@linuxfoundation.org>
Date: Mon, 3 Oct 2022 09:10:59 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Shuai Xue <xueshuai@...ux.alibaba.com>,
Miaohe Lin <linmiaohe@...wei.com>,
Naoya Horiguchi <naoya.horiguchi@....com>,
Huang Ying <ying.huang@...el.com>,
Baolin Wang <baolin.wang@...ux.alibaba.com>,
Bixuan Cui <cuibixuan@...ux.alibaba.com>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH 5.15 34/83] mm,hwpoison: check mm when killing accessing process
From: Shuai Xue <xueshuai@...ux.alibaba.com>
commit 77677cdbc2aa4b5d5d839562793d3d126201d18d upstream.
The GHES code calls memory_failure_queue() from IRQ context to queue work
into workqueue and schedule it on the current CPU. Then the work is
processed in memory_failure_work_func() by kworker and calls
memory_failure().
When a page is already poisoned, commit a3f5d80ea401 ("mm,hwpoison: send
SIGBUS with error virutal address") make memory_failure() call
kill_accessing_process() that:
- holds mmap locking of current->mm
- does pagetable walk to find the error virtual address
- and sends SIGBUS to the current process with error info.
However, the mm of kworker is not valid, resulting in a null-pointer
dereference. So check mm when killing the accessing process.
[akpm@...ux-foundation.org: remove unrelated whitespace alteration]
Link: https://lkml.kernel.org/r/20220914064935.7851-1-xueshuai@linux.alibaba.com
Fixes: a3f5d80ea401 ("mm,hwpoison: send SIGBUS with error virutal address")
Signed-off-by: Shuai Xue <xueshuai@...ux.alibaba.com>
Reviewed-by: Miaohe Lin <linmiaohe@...wei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@....com>
Cc: Huang Ying <ying.huang@...el.com>
Cc: Baolin Wang <baolin.wang@...ux.alibaba.com>
Cc: Bixuan Cui <cuibixuan@...ux.alibaba.com>
Cc: <stable@...r.kernel.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
mm/memory-failure.c | 3 +++
1 file changed, 3 insertions(+)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -700,6 +700,9 @@ static int kill_accessing_process(struct
};
priv.tk.tsk = p;
+ if (!p->mm)
+ return -EFAULT;
+
mmap_read_lock(p->mm);
ret = walk_page_range(p->mm, 0, TASK_SIZE, &hwp_walk_ops,
(void *)&priv);
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