Elena Stepanova added a comment - 2016-08-28 15:50 ATTN nirbhay_c . I can't assign it to two people at once, but whoever sees it first, please check it.

Elena Stepanova added a comment - 2016-08-28 22:08 Please note there are other kinds of failures in that build – corruption, server startup failures. They might be related or different, it's impossible to say at this point.

Sergei Golubchik added a comment - 2016-08-29 16:03 This crash is a case of strict aliasing. Our release builds are not affected, they're compiled with -fno-strict-aliasing . But valgrind builds aren't. Here're the relevant parts of code: sql/log.cc I_List<xid_count_per_binlog> binlog_xid_count_list; ... while ((b= binlog_xid_count_list.get())) { DBUG_ASSERT(b->xid_count == 0); DBUG_ASSERT(!binlog_xid_count_list.head()); sql/log.h I_List<xid_count_per_binlog> binlog_xid_count_list; sql/sql_list.h struct ilink { struct ilink **prev,*next; ... inline void unlink() { if (prev) *prev= next; if (next) next->prev=prev; prev=0 ; next=0; } }; ... class base_ilist { struct ilink *first; struct ilink last; ... inline struct ilink *get() { struct ilink *first_link=first; if (first_link == &last) return 0; first_link->unlink(); // Unlink from list return first_link; } inline struct ilink *head() { return (first != &last) ? first : 0; } What happens here, compiler evaluates the while condition, when doing that it loads binlog_xid_count_list.first into a register. Then it uses this register in evaluating the assertion. It does not notice that binlog_xid_count_list.first was modified meanwhile by ilink::unlink() called from base_ilist::get() .

Sergei Golubchik added a comment - 2016-12-05 11:51 - edited updated buildbot config to disable strict aliasing in valgrind builds