| Bug #105989 | channel_map's read lock is not unlocked | ||
|---|---|---|---|
| Submitted: | 28 Dec 2021 7:49 | Modified: | 3 Jan 2022 12:29 |
| Reporter: | Cheng Zhou | Email Updates: | |
| Status: | Verified | Impact on me: | |
| Category: | MySQL Server: Replication | Severity: | S2 (Serious) |
| Version: | 8.0,8.0.27, 5.7 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
[30 Dec 2021 2:55]
Cheng Zhou
modify version
[3 Jan 2022 12:29]
MySQL Verification Team
Hello Cheng Zhou, Thank you for the report and feedback. Verified as described. regards, Umesh
Description: In function 'longlong Item_source_pos_wait::val_int()' in item_func.cc, the code segment: -------------------------------------------------------- .... channel_map.rdlock(); if (arg_count == 4) { String *channel_str; if (!(channel_str = args[3]->val_str(&value))) { null_value = true; return 0; } .... } else { .... } .... ------------------------------------------------------ When the args count is 4, and the fouth argument is NULL， channel_map's read lock is not unlocked. How to repeat: Connection 1: select master_pos_wait('mysql-bin.000008',728,null,null); Connection 2: SHOW RELAYLOG EVENTS; ------------------------------- The sql 'SHOW RELAYLOG EVENTS' would be blocked when it requires channel_map's write lock. Suggested fix: -------------------------------------------------------- .... channel_map.rdlock(); if (arg_count == 4) { String *channel_str; if (!(channel_str = args[3]->val_str(&value))) { channel_map.unlock(); null_value = true; return 0; } .... } else { .... } ....