> 2023年3月28日 15:54，邹明哲 <mingzhe.zou@xxxxxxxxxxxx> 写道：
>
> From: Eric Wheeler <bcache@xxxxxxxxxxxxxxxxxx>
> Date: 2023-03-28 05:28:05
> To: Mingzhe Zou <mingzhe.zou@xxxxxxxxxxxx>
> Cc: colyli@xxxxxxx,linux-bcache@xxxxxxxxxxxxxxx,zoumingzhe@xxxxxx
> Subject: Re: [PATCH v2] bcache: fixup btree_cache_wait list damage>On Mon, 27 Mar 2023, Mingzhe Zou wrote:
>>
>>> We get a kernel crash about "list_add corruption. next->prev should be
>>> prev (ffff9c801bc01210), but was ffff9c77b688237c. (next=ffffae586d8afe68)."
>>>
>>> crash> struct list_head 0xffff9c801bc01210
>>> struct list_head {
>>> next = 0xffffae586d8afe68,
>>> prev = 0xffffae586d8afe68
>>> }
>>> crash> struct list_head 0xffff9c77b688237c
>>> struct list_head {
>>> next = 0x0,
>>> prev = 0x0
>>> }
>>> crash> struct list_head 0xffffae586d8afe68
>>> struct list_head struct: invalid kernel virtual address: ffffae586d8afe68 type: "gdb_readmem_callback"
>>> Cannot access memory at address 0xffffae586d8afe68
>>>
>>> [230469.019492] Call Trace:
>>> [230469.032041] prepare_to_wait+0x8a/0xb0
>>> [230469.044363] ? bch_btree_keys_free+0x6c/0xc0 [bcache]
>>> [230469.056533] mca_cannibalize_lock+0x72/0x90 [bcache]
>>> [230469.068788] mca_alloc+0x2ae/0x450 [bcache]
>>> [230469.080790] bch_btree_node_get+0x136/0x2d0 [bcache]
>>> [230469.092681] bch_btree_check_thread+0x1e1/0x260 [bcache]
>>> [230469.104382] ? finish_wait+0x80/0x80
>>> [230469.115884] ? bch_btree_check_recurse+0x1a0/0x1a0 [bcache]
>>> [230469.127259] kthread+0x112/0x130
>>> [230469.138448] ? kthread_flush_work_fn+0x10/0x10
>>> [230469.149477] ret_from_fork+0x35/0x40
>>>
>>> bch_btree_check_thread() and bch_dirty_init_thread() maybe call
>>> mca_cannibalize() to cannibalize other cached btree nodes. Only
>>> one thread can do it at a time, so the op of other threads will
>>> be added to the btree_cache_wait list.
>>>
>>> We must call finish_wait() to remove op from btree_cache_wait
>>> before free it's memory address. Otherwise, the list will be
>>> damaged. Also should call bch_cannibalize_unlock() to release
>>> the btree_cache_alloc_lock and wake_up other waiters.
>>>
>>> Signed-off-by: Mingzhe Zou <mingzhe.zou@xxxxxxxxxxxx>
>>
>> Is there a reason not to cc stable?
>>
>> If its ok to cc stable then please add:
>> Cc: stable@xxxxxxxxxxxxxxx
>>
>
> This is an old patch that was not processed last year, and cannot be applied to the latest branch now.
>
> I have updated it to latest branch, cc stable seems unnecessary.
Hi Mingzhe,
Thank you for updating the patch against latest kernel. Let me firstly test and evaluation the change, then I will add these stuffs if necessary.
Coly Li
