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Mahadev konar commented on ZOOKEEPER-897: ----------------------------------------- jared, pat, I am ok without a test case for this one, because its a quite hard to create one. I just wanted someone else to run the tests on there machines just to verify (since I rarely see any problems in c tests on my machine). I will go ahead and commit this patch for now. > C Client seg faults during close > -------------------------------- > > Key: ZOOKEEPER-897 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-897 > Project: Zookeeper > Issue Type: Bug > Components: c client > Reporter: Jared Cantwell > Assignee: Jared Cantwell > Fix For: 3.3.2, 3.4.0 > > Attachments: ZOOKEEEPER-897.diff, ZOOKEEPER-897.patch > > > We observed a crash while closing our c client. It was in the do_io() thread > that was processing as during the close() call. > #0 queue_buffer (list=0x6bd4f8, b=0x0, add_to_front=0) at src/zookeeper.c:969 > #1 0x000000000046234e in check_events (zh=0x6bd480, events=<value optimized > out>) at src/zookeeper.c:1687 > #2 0x0000000000462d74 in zookeeper_process (zh=0x6bd480, events=2) at > src/zookeeper.c:1971 > #3 0x0000000000469c34 in do_io (v=0x6bd480) at src/mt_adaptor.c:311 > #4 0x00007ffff7bc59ca in start_thread () from /lib/libpthread.so.0 > #5 0x00007ffff6f706fd in clone () from /lib/libc.so.6 > #6 0x0000000000000000 in ?? () > We tracked down the sequence of events, and the cause is that input_buffer is > being freed from a thread other than the do_io thread that relies on it: > 1. do_io() call check_events() > 2. if(events&ZOOKEEPER_READ) branch executes > 3. if (rc > 0) branch executes > 4. if (zh->input_buffer != &zh->primer_buffer) branch executes > .....in the meantime...... > 5. zookeeper_close() called > 6. if (inc_ref_counter(zh,0)!=0) branch executes > 7. cleanup_bufs() is called > 8. input_buffer is freed at the end > ..... back to check_events()......... > 9. queue_events() is called on a NULL buffer. > I believe the patch is to only call free_completions() in zookeeper_close() > and not cleanup_bufs(). The original reason cleanup_bufs() was added was to > call any outstanding synhcronous completions, so only free_completions (which > is guarded) is needed. I will submit a patch for review with this change. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.