[MDEV-9468] Client hangs in my_addr_resolve Created: 2016-01-26  Updated: 2016-02-16  Resolved: 2016-02-16

Status: Closed
Project: MariaDB Server
Component/s: Scripts & Clients
Affects Version/s: N/A
Fix Version/s: 10.1.11

Type: Bug Priority: Blocker
Reporter: Elena Stepanova Assignee: Vicențiu Ciorbaru
Resolution: Fixed Votes: 0
Labels: None


 Description   

Several buildbot tests in fulltest2 builder fail due to timeout when run with embedded server:
http://buildbot.askmonty.org/buildbot/builders/kvm-fulltest2/builds/4780/steps/test_5/logs/stdio

I can reproduce it locally, e.g. with main.func_rollback although I have to clean caches after every run (and even then, it does not happen any time, but frequently enough). When it does happen, it keeps eating CPU with this stack trace:

Thread 1 (Thread 0x7f9cb1ddd740 (LWP 32048)):
 
#0  0x00007f9cafd922b3 in select () from /lib64/libc.so.6
 
#1  0x00005617779b910f in my_addr_resolve (ptr=0x561777d5242f <handle_select(THD*, LEX*, select_result*, unsigned long)+399>, loc=0x7ffcc68a1310) at /src/10.1/mysys/my_addr_resolve.c:172
 
#2  0x00005617779b6ef2 in print_stack (frame=0x7f9c8407ae18) at /src/10.1/mysys/safemalloc.c:236
 
#3  0x00005617779b7503 in sf_report_leaked_memory (id=0) at /src/10.1/mysys/safemalloc.c:380
 
#4  0x00005617779b7572 in sf_terminate () at /src/10.1/mysys/safemalloc.c:393
 
#5  0x00007f9cafcebbf9 in __run_exit_handlers () from /lib64/libc.so.6
 
#6  0x00007f9cafcebc45 in exit () from /lib64/libc.so.6
 
#7  0x0000561777986edf in cleanup_and_exit (exit_code=0) at /src/10.1/client/mysqltest.cc:1527
 
#8  0x0000561777998644 in main (argc=29, argv=0x7ffcc68a1788) at /src/10.1/client/mysqltest.cc:9563

The problem appeared in 10.1 tree after these two revisions:

commit b2bd10d4d614924ff22746ce3a49b4e5f755ddc9
 
Author: Vicențiu Ciorbaru <vicentiu@mariadb.org>
 
Date:   Sun Jan 17 22:23:21 2016 +0200
 
 
 
    [MDEV-9427] Server does not build on OpenSUSE 42.1
 
    
    Changed code to comply to C90 standard.
 
 
 
commit 6d3ffd2e3a76873acb4f232f52ccca6a75bf737d
 
Author: Vicențiu Ciorbaru <cvicentiu@gmail.com>
 
Date:   Fri Dec 11 09:16:42 2015 +0200
 
 
 
    Fixed a crash during stacktrace printing if addr2line failed to start.
 
    
    In order to get all the input from addr2line we must read in a loop,
 
    until the response is complete. Also, in case that the response is
 
    malformed, we must not end up reading invalid memory.



 Comments   
Comment by Elena Stepanova [ 2016-01-26 ]

Another variation of the problem, without embedded server, with ps-protocol:
http://buildbot.askmonty.org/buildbot/builders/kvm-fulltest2/builds/4780/steps/test_7/logs/stdio

Also reproducible locally (tried perl ./mtr main.mysql_client_test --ps-protocol ).

hread 1 (Thread 0x7f348d9e8740 (LWP 27039)):
 
#0  0x00007f348bfff293 in __select_nocancel () from /lib64/libc.so.6
 
#1  0x0000559d3e04646c in my_addr_resolve (ptr=0x559d3df79b75 <main+599>, loc=0x7ffc5d1cb720) at /src/10.1-bug/mysys/my_addr_resolve.c:171
 
#2  0x0000559d3e028b0e in print_stack (frame=0x559d3edb0c28) at /src/10.1-bug/mysys/safemalloc.c:236
 
#3  0x0000559d3e02911f in sf_report_leaked_memory (id=0) at /src/10.1-bug/mysys/safemalloc.c:380
 
#4  0x0000559d3e02918e in sf_terminate () at /src/10.1-bug/mysys/safemalloc.c:393
 
#5  0x00007f348bf58bf9 in __run_exit_handlers () from /lib64/libc.so.6
 
#6  0x00007f348bf58c45 in exit () from /lib64/libc.so.6
 
#7  0x0000559d3df79e0b in main (argc=0, argv=0x559d3ed87918) at /src/10.1-bug/tests/mysql_client_fw.c:1505

Comment by Vicențiu Ciorbaru [ 2016-02-16 ]

Fixed with:
https://github.com/MariaDB/server/commit/7d39b28093b06ea67318c257057e93cf891ce896

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