Bug 732925 – Allow sync and async methods to be called with the same GMainContext

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Bug 732925 - Allow sync and async methods to be called with the same GMainContext


Summary:	Allow sync and async methods to be called with the same GMainContext


Status:	RESOLVED FIXED

Product:	libsoup
Classification:	Core
Component:	Misc
Version:	2.47.x
Hardware:	Other Linux

Importance:	Normal normal
Target Milestone:	---
Assigned To:	libsoup-maint@gnome.bugs
QA Contact:	libsoup-maint@gnome.bugs

URL:
Whiteboard:

Depends on:
Blocks:

Reported:	2014-07-08 22:12 UTC by Ross Lagerwall
Modified:	2014-07-19 15:28 UTC

See Also:
GNOME target:	---
GNOME version:	---

Attachments
soup-session: Only process async items from async_run_queue (1.03 KB, patch) 2014-07-08 22:16 UTC, Ross Lagerwall	committed	Details \| Review
program to reproduce the problem (3.21 KB, text/x-csrc) 2014-07-08 22:24 UTC, Ross Lagerwall		Details

Description Ross Lagerwall 2014-07-08 22:12:23 UTC

Since gvfs was ported to use a single SoupSession for sync and async methods, the webdav backend fails when performing concurrent operations.

This is because the operations are run from different threads with the same thread-default GMainContext.

It would be nice if this worked OK (I don't see why the GMainContext should matter for the sync methods of SoupSession).

Thanks

Comment 1 Ross Lagerwall 2014-07-08 22:16:56 UTC

Created attachment 280196 [details] [review]
soup-session: Only process async items from async_run_queue

Only process async items from async_run_queue to allow sync and async
methods to run concurrently in separate threads with the same
async_context.

Comment 2 Ross Lagerwall 2014-07-08 22:23:43 UTC

The attached patch fixes the issue for me.

I have attached a test program which demonstrates the problem (this may require the patch from bug 732783 to be applied).

Sample output:
$ ./concurrent2
GLib-GIO-Message: Using the 'memory' GSettings backend.  Your settings will not be saved or shared with other applications.

(process:3604): libsoup-WARNING **: (soup-session.c:2009):soup_session_process_queue_item: runtime check failed: (item->async)

(process:3604): libsoup-WARNING **: (soup-session.c:1977):soup_session_process_queue_item: runtime check failed: (item->new_api)

(process:3604): libsoup-CRITICAL **: soup_connection_get_ever_used: assertion 'SOUP_IS_CONNECTION (conn)' failed

(process:3604): libsoup-CRITICAL **: soup_message_queue_remove: assertion '!item->removed' failed
Segmentation fault (core dumped)


gdb backtrace at the point of the first warning:

+ Trace 233794

Thread 2 (Thread 0x7ffff56a3700 (LWP 3593))

#0 g_hash_table_lookup
at ghash.c line 1086
#1 param_spec_ht_lookup
at gparam.c line 1002
#2 g_param_spec_pool_lookup
at gparam.c line 1078
#3 g_object_notify
at gobject.c line 1183
#4 object_set_property
at gobject.c line 1378
#5 g_object_new_internal
at gobject.c line 1757
#6 g_object_newv
at gobject.c line 1868
#7 g_object_new
at gobject.c line 1568
#8 new_socket_client
at soup-socket.c line 862
#9 soup_socket_connect_sync_internal
at soup-socket.c line 1033
#10 soup_connection_connect_sync
at soup-connection.c line 479
#11 get_connection
at soup-session.c line 1920
#12 soup_session_process_queue_item
at soup-session.c line 1941
#13 soup_session_real_send_message
at soup-session.c line 2190
#14 soup_session_send_message
at soup-session.c line 2226
#15 thread_fn
#16 g_thread_proxy
at gthread.c line 764
#17 start_thread
from /usr/lib/libpthread.so.0
#18 clone
from /usr/lib/libc.so.6

Thread 1 (Thread 0x7ffff7fc7700 (LWP 3589))

#0 g_logv
at gmessages.c line 1038
#1 g_log
at gmessages.c line 1071
#2 g_warn_message
at gmessages.c line 1104
#3 soup_session_process_queue_item
at soup-session.c line 2009
#4 async_run_queue
at soup-session.c line 2039
#5 idle_run_queue
at soup-session.c line 2073
#6 g_main_dispatch
at gmain.c line 3064
#7 g_main_context_dispatch
at gmain.c line 3663
#8 g_main_context_iterate
at gmain.c line 3734
#9 g_main_loop_run
at gmain.c line 3928
#10 main

Comment 3 Ross Lagerwall 2014-07-08 22:24:13 UTC

Created attachment 280197 [details]
program to reproduce the problem

Comment 4 Dan Winship 2014-07-18 16:51:05 UTC

Comment on attachment 280196 [details] [review]
soup-session: Only process async items from async_run_queue

yes, this looks right

Comment 5 Ross Lagerwall 2014-07-19 15:28:02 UTC

Comment on attachment 280196 [details] [review]
soup-session: Only process async items from async_run_queue

Pushed to master as d0cbd4a11f1d5968db4856dbc0d97496b3cb0d6b. Thanks for the review!