Horton

Re: Use FD_CLOEXEC on ListenSockets (was Re: Refactoring backend fork+exec code)

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: Jeff Janes <jeff.janes@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Andres Freund <andres@anarazel.de>, pgsql-hackers <pgsql-hackers@postgresql.org>, Tristan Partin <tristan@neon.tech>, Peter Geoghegan <pg@bowt.ie>
Date: 2023-10-06T05:30:16Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Avoid 0-length memcpy to NULL with EXEC_BACKEND

  2. Tighten check for --forkchild argument when spawning child process

  3. Add missing PGDLLIMPORT markings

  4. Remove assertions that some compiler say are tautological

  5. Move code for backend startup to separate file

  6. Refactor postmaster child process launching

  7. Move some functions from postmaster.c to a new source file

  8. Split registration of Win32 deadchild callback to separate function

  9. Improve log messages referring to background worker processes

  10. Move initialization of the Port struct to the child process

  11. Pass CAC as an argument to the backend process

  12. Set socket options in child process after forking

  13. Fix references to renamed function in comments

  14. Use MyBackendType in more places to check what process this is

  15. Remove MyAuxProcType, use MyBackendType instead

  16. Replace BackendIds with 0-based ProcNumbers

  17. Redefine backend ID to be an index into the proc array

  18. Remove superfluous 'pgprocno' field from PGPROC

  19. Fix incorrect comment on how BackendStatusArray is indexed

  20. Refactor how InitProcess is called

  21. Pass BackgroundWorker entry in the parameter file in EXEC_BACKEND mode

  22. Refactor CreateSharedMemoryAndSemaphores

  23. Silence Valgrind complaint with EXEC_BACKEND

  24. Adjust obsolete comment explaining set_stack_base().

  25. Print lwlock stats also for aux processes, when built with LWLOCK_STATS

  26. Move canAcceptConnections check from ProcessStartupPacket to caller.

  27. Fix crash on syslogger startup

  28. Refactor ListenSocket array.

  29. Use FD_CLOEXEC on ListenSockets

  30. Don't leak descriptors into subprograms.

  31. Use WaitEventSet API for postmaster's event loop.

  32. Rearrange postmaster's startup sequence for better syslogger results.

  33. Fix and enhance the assertion of no palloc's in a critical section.

On Thu, Oct 05, 2023 at 03:08:37PM +0300, Heikki Linnakangas wrote:
> This seems pretty uncontroversial, and I heard no objections, so I went
> ahead and committed that.

It looks like e29c4643951 is causing issues here.  While doing
benchmarking on a cluster compiled with -O2, I got a crash:
LOG:  system logger process (PID 27924) was terminated by signal 11: Segmentation fault 

Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x000055ef3b9aed20 in pfree ()
(gdb) bt
#0  0x000055ef3b9aed20 in pfree ()
#1  0x000055ef3b7e0e41 in ClosePostmasterPorts ()
#2  0x000055ef3b7e6649 in SysLogger_Start ()
#3  0x000055ef3b7e4413 in PostmasterMain () 

Okay, the backtrace is not that useful.  I'll see if I can get
something better, still it seems like this has broken the way the
syslogger closes these ports.
--
Michael