Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Added some more headers for shared memory, SPI iters and bgworkers #1

Closed
wants to merge 1 commit into from
Closed

Conversation

jamessewell
Copy link
Contributor

What it says on the tin.

This is needed for the other incoming PRs

@eeeebbbbrrrr
Copy link
Contributor

confused about this. the header files go in pgx-pg-sys/include/

@jamessewell
Copy link
Contributor Author

jamessewell commented Apr 16, 2020

Ha! I was copying files from my non fork repo to this one, not enough coffee. Will delete and fix

@eeeebbbbrrrr
Copy link
Contributor

sounds like a winner. I'll merge soon as you do. I'm actually doing some work right now!

@eeeebbbbrrrr eeeebbbbrrrr mentioned this pull request Nov 10, 2021
Sasasu added a commit to Sasasu/pgrx that referenced this pull request Aug 17, 2023
this pr is adding gp7 support and breaking PostgreSQL support.

to use GP7 support. set config to pg12 and enable cshim.

Signed-off-by: Sasasu <[email protected]>
Sasasu added a commit to Sasasu/pgrx that referenced this pull request Aug 17, 2023
this is because pgrx will overwrite the .so file in place.

dlopen will use mmap with MAP_PRIVATE. but if other process is modifing
the file.

dlopen will use MAP_PRIVATE to open the file and map a read-only memory
use mmap(2). usually this memory has copy-on-write. if others is modifing
the file. the previous mapped memory should not change.

but there is a undefined behavior, from man mmap(2):

```
MAP_PRIVATE: It is unspecified whether changes made to the file after the mmap()
call are visible in the mapped region.
```

what actually happens is that the read-only memory in postgresql is modified,
all pointers in the .TEXT segment is mashed up. the call stack looks like

```
 #0  0x0000000000731510 in ?? ()
 pgcentralfoundation#1  0x00007f7a94515132 in core::sync::atomic::AtomicUsize::store (self=0x7f7a95110318 <pgrx_pg_sys::submodules::thread_check::ACTIVE_THREAD::h60448dcb81097e92>, val=0, order=core::sync::atomic::Ordering::Relaxed) at /rustc/90c541806f23a127002de5b4038be731ba1458ca/library/core/src/sync/atomic.rs:2291
 pgcentralfoundation#2  0x00007f7a944f574b in pgrx_pg_sys::submodules::thread_check::init_active_thread::clear_in_child () at src/submodules/thread_check.rs:39
 pgcentralfoundation#3  0x00007f7a962f8a88 in __run_postfork_handlers (who=who@entry=atfork_run_child, do_locking=do_locking@entry=false, lastrun=lastrun@entry=2) at register-atfork.c:187
 pgcentralfoundation#4  0x00007f7a962df773 in __libc_fork () at fork.c:109
 pgcentralfoundation#5  0x00005555e66ad948 in fork_process () at fork_process.c:61
 pgcentralfoundation#6  0x00005555e66a5d48 in StartAutoVacWorker () at autovacuum.c:1543
 pgcentralfoundation#7  0x00005555e66c43f7 in StartAutovacuumWorker () at postmaster.c:6155
 pgcentralfoundation#8  0x00005555e66c3d21 in sigusr1_handler (postgres_signal_arg=10) at postmaster.c:5820
 pgcentralfoundation#9  <signal handler called>
 pgcentralfoundation#10 0x00007f7a9630eb84 in __GI___select (nfds=6, readfds=0x7ffc61c2fa40, writefds=0x0, exceptfds=0x0, timeout=0x7ffc61c2f9b0) at ../sysdeps/unix/sysv/linux/select.c:69
 pgcentralfoundation#11 0x00005555e66be343 in ServerLoop () at postmaster.c:1950
 pgcentralfoundation#12 0x00005555e66bdb0f in PostmasterMain (argc=5, argv=0x5555e8fb5490) at postmaster.c:1631
 pgcentralfoundation#13 0x00005555e6560e41 in main (argc=5, argv=0x5555e8fb5490) at main.c:240
```

the is `pgrx_pg_sys` try to run the postfork hook. but the variable `ACTIVE_THREAD`
and the code binary does not in the previous place.
Sasasu added a commit to Sasasu/pgrx that referenced this pull request Aug 17, 2023
this is because pgrx will overwrite the .so file in place.

dlopen will use mmap with MAP_PRIVATE. but if other process is modifing
the file.

dlopen will use MAP_PRIVATE to open the file and map a read-only memory
use mmap(2). usually this memory has copy-on-write. if others is modifing
the file. the previous mapped memory should not change.

but there is a undefined behavior, from man mmap(2):

```
MAP_PRIVATE: It is unspecified whether changes made to the file after the mmap()
call are visible in the mapped region.
```

what actually happens is that the read-only memory in postgresql is modified,
all pointers in the .TEXT segment is mashed up. the call stack looks like

```
 #0  0x0000000000731510 in ?? ()
 pgcentralfoundation#1  0x00007f7a94515132 in core::sync::atomic::AtomicUsize::store (self=0x7f7a95110318 <pgrx_pg_sys::submodules::thread_check::ACTIVE_THREAD::h60448dcb81097e92>, val=0, order=core::sync::atomic::Ordering::Relaxed) at /rustc/90c541806f23a127002de5b4038be731ba1458ca/library/core/src/sync/atomic.rs:2291
 pgcentralfoundation#2  0x00007f7a944f574b in pgrx_pg_sys::submodules::thread_check::init_active_thread::clear_in_child () at src/submodules/thread_check.rs:39
 pgcentralfoundation#3  0x00007f7a962f8a88 in __run_postfork_handlers (who=who@entry=atfork_run_child, do_locking=do_locking@entry=false, lastrun=lastrun@entry=2) at register-atfork.c:187
 pgcentralfoundation#4  0x00007f7a962df773 in __libc_fork () at fork.c:109
 pgcentralfoundation#5  0x00005555e66ad948 in fork_process () at fork_process.c:61
 pgcentralfoundation#6  0x00005555e66a5d48 in StartAutoVacWorker () at autovacuum.c:1543
 pgcentralfoundation#7  0x00005555e66c43f7 in StartAutovacuumWorker () at postmaster.c:6155
 pgcentralfoundation#8  0x00005555e66c3d21 in sigusr1_handler (postgres_signal_arg=10) at postmaster.c:5820
 pgcentralfoundation#9  <signal handler called>
 pgcentralfoundation#10 0x00007f7a9630eb84 in __GI___select (nfds=6, readfds=0x7ffc61c2fa40, writefds=0x0, exceptfds=0x0, timeout=0x7ffc61c2f9b0) at ../sysdeps/unix/sysv/linux/select.c:69
 pgcentralfoundation#11 0x00005555e66be343 in ServerLoop () at postmaster.c:1950
 pgcentralfoundation#12 0x00005555e66bdb0f in PostmasterMain (argc=5, argv=0x5555e8fb5490) at postmaster.c:1631
 pgcentralfoundation#13 0x00005555e6560e41 in main (argc=5, argv=0x5555e8fb5490) at main.c:240
```

the is `pgrx_pg_sys` try to run the postfork hook. but the variable `ACTIVE_THREAD`
and the code binary does not in the previous place.
Sasasu added a commit to Sasasu/pgrx that referenced this pull request Aug 17, 2023
this is because pgrx will overwrite the .so file in place.

dlopen will use mmap with MAP_PRIVATE. but if other process is modifying
the file.

dlopen will use MAP_PRIVATE to open the file and map a read-only memory
use mmap(2). usually this memory has copy-on-write. if others is modifying
the file. the previously mapped memory should not change.

but there is a undefined behavior, from man mmap(2):

```
MAP_PRIVATE: It is unspecified whether changes made to the file after the mmap()
call are visible in the mapped region.
```

what actually happens is that the read-only memory in postgresql is modified,
and all pointers in the .TEXT segment is mashed up. the call stack looks like

```
 #0  0x0000000000731510 in ?? ()
 pgcentralfoundation#1  0x00007f7a94515132 in core::sync::atomic::AtomicUsize::store (self=0x7f7a95110318 <pgrx_pg_sys::submodules::thread_check::ACTIVE_THREAD::h60448dcb81097e92>, val=0, order=core::sync::atomic::Ordering::Relaxed) at /rustc/90c541806f23a127002de5b4038be731ba1458ca/library/core/src/sync/atomic.rs:2291
 pgcentralfoundation#2  0x00007f7a944f574b in pgrx_pg_sys::submodules::thread_check::init_active_thread::clear_in_child () at src/submodules/thread_check.rs:39
 pgcentralfoundation#3  0x00007f7a962f8a88 in __run_postfork_handlers (who=who@entry=atfork_run_child, do_locking=do_locking@entry=false, lastrun=lastrun@entry=2) at register-atfork.c:187
 pgcentralfoundation#4  0x00007f7a962df773 in __libc_fork () at fork.c:109
 pgcentralfoundation#5  0x00005555e66ad948 in fork_process () at fork_process.c:61
 pgcentralfoundation#6  0x00005555e66a5d48 in StartAutoVacWorker () at autovacuum.c:1543
 pgcentralfoundation#7  0x00005555e66c43f7 in StartAutovacuumWorker () at postmaster.c:6155
 pgcentralfoundation#8  0x00005555e66c3d21 in sigusr1_handler (postgres_signal_arg=10) at postmaster.c:5820
 pgcentralfoundation#9  <signal handler called>
 pgcentralfoundation#10 0x00007f7a9630eb84 in __GI___select (nfds=6, readfds=0x7ffc61c2fa40, writefds=0x0, exceptfds=0x0, timeout=0x7ffc61c2f9b0) at ../sysdeps/unix/sysv/linux/select.c:69
 pgcentralfoundation#11 0x00005555e66be343 in ServerLoop () at postmaster.c:1950
 pgcentralfoundation#12 0x00005555e66bdb0f in PostmasterMain (argc=5, argv=0x5555e8fb5490) at postmaster.c:1631
 pgcentralfoundation#13 0x00005555e6560e41 in main (argc=5, argv=0x5555e8fb5490) at main.c:240
```

the is `pgrx_pg_sys` try to run the postfork hook. but the variable `ACTIVE_THREAD`
and the code binary does not in the previous place.
eeeebbbbrrrr added a commit that referenced this pull request Nov 2, 2024
I can't quite explain why, but this function was deadlocking with this
backtrace:

```
* thread #1, name = 'cargo-pgrx', stop reason = signal SIGSTOP
  * frame #0: 0x00007fbe1eeb288d libc.so.6`syscall at syscall.S:38
    frame #1: 0x000055aee526c5d3 cargo-pgrx`std::sys::sync::mutex::futex::Mutex::lock_contended::h6389e2305b0b005c [inlined] std::sys::pal::unix::futex::futex_wait::h30abf43e2d55aa33 at futex.rs:67:21
    frame #2: 0x000055aee526c590 cargo-pgrx`std::sys::sync::mutex::futex::Mutex::lock_contended::h6389e2305b0b005c at futex.rs:57:13
    frame #3: 0x000055aee4157835 cargo-pgrx`std::sync::mutex::Mutex$LT$T$GT$::lock::h4d2bb65800cc6fd3 at futex.rs:29:13
    frame #4: 0x000055aee41577ed cargo-pgrx`std::sync::mutex::Mutex$LT$T$GT$::lock::h4d2bb65800cc6fd3(self=0x000055aee6926c20) at mutex.rs:317:24
    frame #5: 0x000055aee406c779 cargo-pgrx`cargo_pgrx::command::install::get_git_hash::ha84d504db9d1bba8(manifest_path=0x00007ffdc43b83b0) at install.rs:507:9
    frame #6: 0x000055aee406d6e9 cargo-pgrx`cargo_pgrx::command::install::filter_contents::h8c710847129ba6be(manifest_path=0x00007ffdc43b8d10, input=String @ 0x00007ffdc43b8940) at install.rs:541:46
```
eeeebbbbrrrr added a commit that referenced this pull request Nov 2, 2024
I can't quite explain why, but this function was deadlocking with this
backtrace:

```
* thread #1, name = 'cargo-pgrx', stop reason = signal SIGSTOP
  * frame #0: 0x00007fbe1eeb288d libc.so.6`syscall at syscall.S:38
    frame #1: 0x000055aee526c5d3 cargo-pgrx`std::sys::sync::mutex::futex::Mutex::lock_contended::h6389e2305b0b005c [inlined] std::sys::pal::unix::futex::futex_wait::h30abf43e2d55aa33 at futex.rs:67:21
    frame #2: 0x000055aee526c590 cargo-pgrx`std::sys::sync::mutex::futex::Mutex::lock_contended::h6389e2305b0b005c at futex.rs:57:13
    frame #3: 0x000055aee4157835 cargo-pgrx`std::sync::mutex::Mutex$LT$T$GT$::lock::h4d2bb65800cc6fd3 at futex.rs:29:13
    frame #4: 0x000055aee41577ed cargo-pgrx`std::sync::mutex::Mutex$LT$T$GT$::lock::h4d2bb65800cc6fd3(self=0x000055aee6926c20) at mutex.rs:317:24
    frame #5: 0x000055aee406c779 cargo-pgrx`cargo_pgrx::command::install::get_git_hash::ha84d504db9d1bba8(manifest_path=0x00007ffdc43b83b0) at install.rs:507:9
    frame #6: 0x000055aee406d6e9 cargo-pgrx`cargo_pgrx::command::install::filter_contents::h8c710847129ba6be(manifest_path=0x00007ffdc43b8d10, input=String @ 0x00007ffdc43b8940) at install.rs:541:46
```
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

Successfully merging this pull request may close these issues.

2 participants