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DescriptionAlexey Tikhonov
2019-12-19 11:22:40 UTC
When internal watchdog detects that process is locked it handles situation this way:
```
if (getpid() == getpgrp()) {
kill(-getpgrp(), SIGTERM);
} else {
_exit(1);
}
```
-- so in case of parent process (vast majority of cases) it sends SIGTERM to the whole group of processes, including itself.
The problem is this signal is handled by libtevent handler:
```
server_setup()->tevent_add_signal(event_ctx, event_ctx, SIGTERM, 0, default_quit, ctx);
```
(and also by `be_process_install_sigterm_handler()` but this should go away)
And this handler just adds event for processing into tevent mainloop. But if tevent mainloop is stuck (exactly the case that triggers watchdog) then this event will not be processed and this makes watchdog useless.
This behavior can actually be seen in bz 1625937 where backend process is only terminated after very-long-running sync task is finally completed.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHBA-2020:1863
When internal watchdog detects that process is locked it handles situation this way: ``` if (getpid() == getpgrp()) { kill(-getpgrp(), SIGTERM); } else { _exit(1); } ``` -- so in case of parent process (vast majority of cases) it sends SIGTERM to the whole group of processes, including itself. The problem is this signal is handled by libtevent handler: ``` server_setup()->tevent_add_signal(event_ctx, event_ctx, SIGTERM, 0, default_quit, ctx); ``` (and also by `be_process_install_sigterm_handler()` but this should go away) And this handler just adds event for processing into tevent mainloop. But if tevent mainloop is stuck (exactly the case that triggers watchdog) then this event will not be processed and this makes watchdog useless. This behavior can actually be seen in bz 1625937 where backend process is only terminated after very-long-running sync task is finally completed.