Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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10.1, 10.2, 10.3, 10.4, 10.5
Description
For some reason, I am only seeing this reported for 10.4 and 10.5, not for earlier versions.
To repeat (I used GCC 9.2.1; clang’s UBSAN would not even bootstrap):
mkdir build; cd build |
cmake -DCONC_WITH_{UNITTEST,SSL}=OFF -DWITH_EMBEDDED_SERVER=OFF -DWITH_UNIT_TESTS=OFF -DCMAKE_BUILD_TYPE=Debug -DPLUGIN_{ARCHIVE,TOKUDB,MROONGA,OQGRAPH,ROCKSDB,CONNECT,SPIDER}=NO -DWITH_SAFEMALLOC=OFF -DWITH_{SSL,ZLIB}=system "$@" -DCMAKE_C{,XX}_FLAGS='-O2 -march=native' -DWITH_UBSAN=ON .. |
make -j$(nproc) |
cd mysql-test |
nice ./mtr --parallel=$(($(nproc) * 3 / 2)) --force --retry=0 --max-test-fail=0 --big-test |
grep 'log.*runtime error' var/*/log/mysqld*err*|cut -d: -f2-|sed -e 's/0x[0-9a-fA-F]*/0xXXX/'|sort|uniq -c|sort -nr |
The top of the output looks like this:
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10.4 576c96a9385f20cf4b6fe685e079dcf8026c3a24 |
1740 /mariadb/10.4/sql/log.cc:3812:25: runtime error: member access within address 0xXXX which does not point to an object of type 'xid_count_per_binlog'
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1740 /mariadb/10.4/sql/log.cc:3714:41: runtime error: member access within address 0xXXX which does not point to an object of type 'xid_count_per_binlog'
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1740 /mariadb/10.4/sql/log.cc:3694:29: runtime error: member access within address 0xXXX which does not point to an object of type 'xid_count_per_binlog'
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For some reason, not all such access is flagged. Here is a sample around line 3694:
if (!(new_xid_list_entry = (xid_count_per_binlog *) |
my_multi_malloc(MYF(MY_WME),
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&entry_mem, sizeof(xid_count_per_binlog), |
&name_mem, len,
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NULL)))
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goto err; |
memcpy(name_mem, log_file_name+off, len); |
new_xid_list_entry->binlog_name= name_mem;
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new_xid_list_entry->binlog_name_len= (int)len; |
new_xid_list_entry->xid_count= 0;
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new_xid_list_entry->notify_count= 0;
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The problem appears to be that no constructor for xid_count_per_binlog is being called, and thus the vtable will not be initialized. It looks like there is no constructor at all provided for xid_count_per_binlog, even though it is a derived class:
struct xid_count_per_binlog : public ilink { |
…
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xid_count_per_binlog(); /* Give link error if constructor used. */ |
};
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A definition of MYSQL_BIN_LOG::xid_count_per_binlog::xid_count_per_binlog() is nowhere to be seen. Side note: starting with 10.4, we could use the standard C++11 way to omit default member functions:
xid_count_per_binlog() = delete; |
Here is an attempted patch, which fails to compile due to missing constructor:
diff --git a/sql/log.cc b/sql/log.cc
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index 7f632b43cb6..9a5081ab94a 100644
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--- a/sql/log.cc
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+++ b/sql/log.cc
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@@ -3684,13 +3684,13 @@ bool MYSQL_BIN_LOG::open(const char *log_name,
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size_t off= dirname_length(log_file_name);
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size_t len= strlen(log_file_name) - off;
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char *entry_mem, *name_mem;
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- if (!(new_xid_list_entry = (xid_count_per_binlog *)
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- my_multi_malloc(MYF(MY_WME),
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- &entry_mem, sizeof(xid_count_per_binlog),
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- &name_mem, len,
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- NULL)))
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+ if (!my_multi_malloc(MYF(MY_WME),
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+ &entry_mem, sizeof(xid_count_per_binlog),
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+ &name_mem, len,
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+ NULL)))
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goto err;
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memcpy(name_mem, log_file_name+off, len);
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+ new_xid_list_entry = new (entry_mem) xid_count_per_binlog();
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new_xid_list_entry->binlog_name= name_mem;
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new_xid_list_entry->binlog_name_len= (int)len;
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new_xid_list_entry->xid_count= 0; |
(Note: my_multi_malloc() would return entry_mem.)
I do not know why I am not seeing any UBSAN errors reported for sql/log.cc in 10.2 or 10.3. It does not look like the code has changed. So, the affectedVersion and fixVersion may need to be revised.
Attachments
Issue Links
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