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From: Dan Carpenter <dan.carpenter@linaro.org>
To: aahringo@redhat.com
Cc: gfs2@lists.linux.dev
Subject: [bug report] dlm: avoid blocking receive at the end of recovery
Date: Wed, 17 Apr 2024 21:11:08 +0300	[thread overview]
Message-ID: <9ad928eb-2ece-4ad9-a79c-d2bce228e4bc@moroto.mountain> (raw)

Hello Alexander Aring,

Commit c288745f1d4a ("dlm: avoid blocking receive at the end of
recovery") from Apr 2, 2024 (linux-next), leads to the following
Smatch static checker warning:

    fs/dlm/lock.c:4859 _receive_message()
    warn: sleeping in atomic context

fs/dlm/lock.c
  4851  
  4852          case cpu_to_le32(DLM_MSG_LOOKUP_REPLY):
  4853                  receive_lookup_reply(ls, ms);
  4854                  break;
  4855  
  4856          /* other messages */
  4857  
  4858          case cpu_to_le32(DLM_MSG_PURGE):
  4859                  receive_purge(ls, ms);
                        ^^^^^^^^^^^^^
Does a mutex_lock() so preempt needs to be enabled.

  4860                  break;
  4861  
  4862          default:
  4863                  log_error(ls, "unknown message type %d",
  4864                            le32_to_cpu(ms->m_type));
  4865          }

The problematic call tree is:

dlm_receive_buffer() <- disables preempt
-> dlm_receive_message() <- disables preempt
   -> _receive_message()

That patch moved _receive_message() to be called under the lock.

regards,
dan carpenter

                 reply	other threads:[~2024-04-17 18:11 UTC|newest]

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