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authorShuai Xue <xueshuai@linux.alibaba.com>2022-09-14 14:49:35 +0800
committerAndrew Morton <akpm@linux-foundation.org>2022-09-26 12:14:34 -0700
commit77677cdbc2aa4b5d5d839562793d3d126201d18d (patch)
treeaa8a70e7ea30366a2e207000f3923e01515e7cbd /mm/memory-failure.c
parent317314527d173e1f139ceaf8cb87cb1746abf240 (diff)
downloadlwn-77677cdbc2aa4b5d5d839562793d3d126201d18d.tar.gz
lwn-77677cdbc2aa4b5d5d839562793d3d126201d18d.zip
mm,hwpoison: check mm when killing accessing process
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@linux-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@linux.alibaba.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Bixuan Cui <cuibixuan@linux.alibaba.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/memory-failure.c')
-rw-r--r--mm/memory-failure.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index e424a9dac749..e7ac570dda75 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -745,6 +745,9 @@ static int kill_accessing_process(struct task_struct *p, unsigned long pfn,
};
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);