re: jbd: Add fixed tracepoints

["Lukáš Czerner" <lczerner@redhat.com>]

On Wed, 18 Mar 2015, Dan Carpenter wrote:

> Date: Wed, 18 Mar 2015 11:05:33 +0300
> From: Dan Carpenter <dan.carpenter@oracle.com>
> To: lczerner@redhat.com
> Cc: linux-ext4@vger.kernel.org
> Subject: re: jbd: Add fixed tracepoints
> 
> Hello Lukas Czerner,
> 
> The patch 99cb1a318c37: "jbd: Add fixed tracepoints" from May 23,
> 2011, leads to the following static checker warning:

Hi Dan,

thanks for the report. I'll send a fix.

-Lukas

> 
> 	fs/jbd/commit.c:1016 journal_commit_transaction()
> 	warn: 'commit_transaction' was already freed.
> 
> fs/jbd/commit.c
>    993          spin_unlock(&journal->j_state_lock);
>    994  
>    995          if (commit_transaction->t_checkpoint_list == NULL &&
>    996              commit_transaction->t_checkpoint_io_list == NULL) {
>    997                  __journal_drop_transaction(journal, commit_transaction);
>                                                             ^^^^^^^^^^^^^^^^^^
> Freed here.
> 
>    998          } else {
>    999                  if (journal->j_checkpoint_transactions == NULL) {
>   1000                          journal->j_checkpoint_transactions = commit_transaction;
>   1001                          commit_transaction->t_cpnext = commit_transaction;
>   1002                          commit_transaction->t_cpprev = commit_transaction;
>   1003                  } else {
>   1004                          commit_transaction->t_cpnext =
>   1005                                  journal->j_checkpoint_transactions;
>   1006                          commit_transaction->t_cpprev =
>   1007                                  commit_transaction->t_cpnext->t_cpprev;
>   1008                          commit_transaction->t_cpnext->t_cpprev =
>   1009                                  commit_transaction;
>   1010                          commit_transaction->t_cpprev->t_cpnext =
>   1011                                  commit_transaction;
>   1012                  }
>   1013          }
>   1014          spin_unlock(&journal->j_list_lock);
>   1015  
>   1016          trace_jbd_end_commit(journal, commit_transaction);
>                                               ^^^^^^^^^^^^^^^^^^
> Dereferenced here.
> 
>   1017          jbd_debug(1, "JBD: commit %d complete, head %d\n",
>   1018                    journal->j_commit_sequence, journal->j_tail_sequence);
>   1019  
>   1020          wake_up(&journal->j_wait_done_commit);
>   1021  }
> 
> regards,
> dan carpenter
>