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MSAN: do not compare uninitailized memory in log_in_use

Description

Strings are compared with memcmp, which results in comparing uninitailized bytes. This has to be supressed or changed to str(n)cmp.

Environment

None

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Activity

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Zsolt Parragi June 18, 2018 at 7:49 AM

Example call stack for the issue, with rpl_flushlog_loop MTR test:

 

==321==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x8bad0a in _Z10log_in_usePKc /work/src/sql/sql_repl.cc:264
#1 0x8bad0a in ?? ??:0
#2 0xf124de in _ZN13MYSQL_BIN_LOG10purge_logsEPKcbbbPy /work/src/sql/log.cc:4085
#3 0xf124de in ?? ??:0
#4 0xf11af9 in _ZN13MYSQL_BIN_LOG15purge_first_logEP14Relay_log_infob /work/src/sql/log.cc:3975
#5 0xf11af9 in ?? ??:0
#6 0x6a5b43 in _ZL10next_eventP14Relay_log_info /work/src/sql/slave.cc:4894
#7 0x6a5b43 in ?? ??:0
#8 0x69f0ef in _ZL20exec_relay_log_eventP3THDP14Relay_log_info /work/src/sql/slave.cc:2574
#9 0x69f0ef in ?? ??:0
#10 0x68b7ec in handle_slave_sql /work/src/sql/slave.cc:3461
#11 0x68b7ec in ?? ??:0
#12 0x1211ee9 in pfs_spawn_thread /work/src/storage/perfschema/pfs.cc:1015
#13 0x1211ee9 in ?? ??:0
#14 0x5f78f4 in ZN6_msan10MsanThread11ThreadStartEv :?
#15 0x5f78f4 in ?? ??:0
#16 0x7fd3df76c7fb in start_thread /build/glibc-itYbWN/glibc-2.26/nptl/pthread_create.c:465
#17 0x7fd3df76c7fb in ?? ??:0
#18 0x7fd3de2cbb5e in clone /build/glibc-itYbWN/glibc-2.26/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:95
#19 0x7fd3de2cbb5e in ?? ??:0

Uninitialized value was created by an allocation of 'linfo' in the stack frame of function '_Z17mysql_binlog_sendP3THDPcyt'
#0 0x8bb600 in _Z17mysql_binlog_sendP3THDPcyt /work/src/sql/sql_repl.cc:441
#1 0x8bb600 in ?? ??:0

Done

Details

Assignee

Reporter

Upstream Bug URL

https://bugs.mysql.com/bug.php?id=90238

Time tracking

4h logged

Fix versions

Affects versions

Priority

Smart Checklist

Created March 26, 2018 at 9:13 AM
Updated June 18, 2018 at 7:49 AM
Resolved March 28, 2018 at 8:29 AM