Re: [PATCH iproute2-rc 1/2] rdma: Fix core dump when pretty is used

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On 2024/1/2 16:32, Leon Romanovsky wrote:
On Tue, Jan 02, 2024 at 03:44:29PM +0800, Chengchang Tang wrote:

On 2023/12/30 1:21, Stephen Hemminger wrote:
On Fri, 29 Dec 2023 14:52:40 +0800
Junxian Huang <huangjunxian6@xxxxxxxxxxxxx> wrote:

From: Chengchang Tang <tangchengchang@xxxxxxxxxx>

There will be a core dump when pretty is used as the JSON object
hasn't been opened and closed properly.

Before:
$ rdma res show qp -jp -dd
[ {
      "ifindex": 1,
      "ifname": "hns_1",
      "port": 1,
      "lqpn": 1,
      "type": "GSI",
      "state": "RTS",
      "sq-psn": 0,
      "comm": "ib_core"
},
"drv_sq_wqe_cnt": 128,
"drv_sq_max_gs": 2,
"drv_rq_wqe_cnt": 512,
"drv_rq_max_gs": 1,
rdma: json_writer.c:130: jsonw_end: Assertion `self->depth > 0' failed.
Aborted (core dumped)

After:
$ rdma res show qp -jp -dd
[ {
          "ifindex": 2,
          "ifname": "hns_2",
          "port": 1,
          "lqpn": 1,
          "type": "GSI",
          "state": "RTS",
          "sq-psn": 0,
          "comm": "ib_core",{
              "drv_sq_wqe_cnt": 128,
              "drv_sq_max_gs": 2,
              "drv_rq_wqe_cnt": 512,
              "drv_rq_max_gs": 1,
              "drv_ext_sge_sge_cnt": 256
          }
      } ]

Fixes: 331152752a97 ("rdma: print driver resource attributes")
Signed-off-by: Chengchang Tang <tangchengchang@xxxxxxxxxx>
Signed-off-by: Junxian Huang <huangjunxian6@xxxxxxxxxxxxx>
This code in rdma seems to be miking json and newline functionality
which creates bug traps.

Also the json should have same effective output in pretty and non-pretty mode.
It looks like since pretty mode add extra object layer, the nesting of {} would be
different.

The conversion to json_print() was done but it isn't using same conventions
as ip or tc.

The correct fix needs to go deeper and hit other things.

Hi, Stephen,

The root cause of this issue is that close_json_object() is being called in
newline_indent(), resulting in a mismatch
of {}.

When fixing this problem, I was unsure why a newline() is needed in pretty
mode, so I simply kept this logic and
solved the issue of open_json_object() and close_json_object() not matching.
However, If the output of pretty mode
and not-pretty mode should be the same, then this problem can be resolved by
deleting this newline_indent().
Stephen didn't say that output of pretty and not-pretty should be the
same, but he said that JSON logic should be the same.

Thanks

Hi, Leon,

Thank you for your reply. But I'm not sure what you mean by JSON logic? I understand that pretty and not-pretty JSON should have the same content, but just difference display effects.
Do you mean that they only need to have the same structure?

Or, let's get back to this question. In the JSON format output, the newline() here seems unnecessary, because json_print() can solve the line break problems during printing. So I think the newline() here can be removed at least when outputting in JSON format.

Thanks,
Chengchang Tang

I believe the original developer may not have realized that
close_json_object() is being called in newline(), which leads
to this problem. To improve the code's readability, I would try to strip out
close_json_obejct() from newline().

Thanks,
Chengchang Tang

.






[Index of Archives]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Photo]     [Yosemite News]     [Yosemite Photos]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux