Re: [PATCH for-next v2] RDMA/rxe: Fix mr->map double free

[Yanjun Zhu <yanjun.zhu@linux.dev>]

在 2022/11/12 11:29, lizhijian@fujitsu.com 写道:
> ping...
Hi, Zhijian

The changes are too much. I need time to delve into it.

Zhu Yanjun

> 
> Hi Yanjun
> 
> 
> I hope you could take a look to this bug fix more earlier.
> 
> 
> Thanks
> Zhijian
> 
> 
> 
> On 30/10/2022 11:04, Li Zhijian wrote:
>> rxe_mr_cleanup() which tries to free mr->map again will be called
>> when rxe_mr_init_user() fails.
>>
>> [43895.939883] CPU: 0 PID: 4917 Comm: rdma_flush_serv Kdump: loaded Not tainted 6.1.0-rc1-roce-flush+ #25
>> [43895.942341] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
>> [43895.945208] Call Trace:
>> [43895.946130]  <TASK>
>> [43895.946931]  dump_stack_lvl+0x45/0x5d
>> [43895.948049]  panic+0x19e/0x349
>> [43895.949010]  ? panic_print_sys_info.part.0+0x77/0x77
>> [43895.950356]  ? asm_sysvec_apic_timer_interrupt+0x16/0x20
>> [43895.952589]  ? preempt_count_sub+0x14/0xc0
>> [43895.953809]  end_report.part.0+0x54/0x7c
>> [43895.954993]  ? rxe_mr_cleanup+0x9d/0xf0 [rdma_rxe]
>> [43895.956406]  kasan_report.cold+0xa/0xf
>> [43895.957668]  ? rxe_mr_cleanup+0x9d/0xf0 [rdma_rxe]
>> [43895.959090]  rxe_mr_cleanup+0x9d/0xf0 [rdma_rxe]
>> [43895.960502]  __rxe_cleanup+0x10a/0x1e0 [rdma_rxe]
>> [43895.961983]  rxe_reg_user_mr+0xb7/0xd0 [rdma_rxe]
>> [43895.963456]  ib_uverbs_reg_mr+0x26a/0x480 [ib_uverbs]
>> [43895.964921]  ? __lock_acquire+0x876/0x31e0
>> [43895.966182]  ? ib_uverbs_ex_create_wq+0x630/0x630 [ib_uverbs]
>> [43895.967739]  ? uverbs_fill_udata+0x1c6/0x330 [ib_uverbs]
>> [43895.969204]  ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x1a2/0x250 [ib_uverbs]
>> [43895.971126]  ? ib_uverbs_handler_UVERBS_METHOD_QUERY_CONTEXT+0x1a0/0x1a0 [ib_uverbs]
>> [43895.973094]  ? ib_uverbs_handler_UVERBS_METHOD_QUERY_CONTEXT+0x1a0/0x1a0 [ib_uverbs]
>> [43895.975096]  ? uverbs_fill_udata+0x25f/0x330 [ib_uverbs]
>> [43895.976466]  ib_uverbs_cmd_verbs+0x1397/0x15a0 [ib_uverbs]
>> [43895.977930]  ? ib_uverbs_handler_UVERBS_METHOD_QUERY_CONTEXT+0x1a0/0x1a0 [ib_uverbs]
>> [43895.979937]  ? uverbs_fill_udata+0x330/0x330 [ib_uverbs]
>>
>> This issue was fistrly exposed since
>> commit: b18c7da63fcb ("RDMA/rxe: Fix memory leak in error path code")
>> and then we fixed it in
>> commit: 8ff5f5d9d8cf ("RDMA/rxe: Prevent double freeing rxe_map_set()")
>> but this fix was reverted together at last by
>> commit: 1e75550648da (Revert "RDMA/rxe: Create duplicate mapping tables for FMRs")
>>
>> Fixes: 1e75550648da (Revert "RDMA/rxe: Create duplicate mapping tables for FMRs")
>> Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
>> ---
>>    drivers/infiniband/sw/rxe/rxe_mr.c | 9 ++-------
>>    1 file changed, 2 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
>> index d4f10c2d1aa7..7c99d1591580 100644
>> --- a/drivers/infiniband/sw/rxe/rxe_mr.c
>> +++ b/drivers/infiniband/sw/rxe/rxe_mr.c
>> @@ -99,6 +99,7 @@ static int rxe_mr_alloc(struct rxe_mr *mr, int num_buf)
>>    		kfree(mr->map[i]);
>>    
>>    	kfree(mr->map);
>> +	mr->map = NULL;
>>    err1:
>>    	return -ENOMEM;
>>    }
>> @@ -122,7 +123,6 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
>>    	int			num_buf;
>>    	void			*vaddr;
>>    	int err;
>> -	int i;
>>    
>>    	umem = ib_umem_get(&rxe->ib_dev, start, length, access);
>>    	if (IS_ERR(umem)) {
>> @@ -163,9 +163,8 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
>>    				pr_warn("%s: Unable to get virtual address\n",
>>    						__func__);
>>    				err = -ENOMEM;
>> -				goto err_cleanup_map;
>> +				goto err_release_umem;
>>    			}
>> -
>>    			buf->addr = (uintptr_t)vaddr;
>>    			buf->size = PAGE_SIZE;
>>    			num_buf++;
>> @@ -182,10 +181,6 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
>>    
>>    	return 0;
>>    
>> -err_cleanup_map:
>> -	for (i = 0; i < mr->num_map; i++)
>> -		kfree(mr->map[i]);
>> -	kfree(mr->map);
>>    err_release_umem:
>>    	ib_umem_release(umem);
>>    err_out: