Bug 786656 – gdm crashes on unlocking my session.

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Bug 786656 - gdm crashes on unlocking my session.


Summary:	gdm crashes on unlocking my session.


Status:	RESOLVED FIXED

Product:	gdm
Classification:	Core
Component:	general
Version:	3.25.x
Hardware:	Other Linux

Importance:	Normal critical
Target Milestone:	---
Assigned To:	GDM maintainers
QA Contact:	GDM maintainers

URL:
Whiteboard:

Depends on:
Blocks:

Reported:	2017-08-22 22:10 UTC by Hussam Al-Tayeb
Modified:	2017-08-23 13:36 UTC

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

Attachments
valgrind log. (5.25 KB, text/plain) 2017-08-23 11:24 UTC, Hussam Al-Tayeb		Details
manager: fix dangling pointer free (3.42 KB, patch) 2017-08-23 13:34 UTC, Ray Strode [halfline]	committed	Details \| Review

Description Hussam Al-Tayeb 2017-08-22 22:10:40 UTC

I am getting the following crash on unlocking my session


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License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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Reading symbols from /usr/bin/gdm...done.
[New LWP 1517]
[New LWP 1538]
[New LWP 1518]
[New LWP 1520]
[New LWP 1519]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".
Core was generated by `/usr/bin/gdm'.
Program terminated with signal SIGSEGV, Segmentation fault.

+ Trace 237841

Thread 2 (Thread 0x7fbea9811700 (LWP 1538))

#0 syscall
#1 g_cond_wait_until
at gthread-posix.c line 1442
#2 g_async_queue_pop_intern_unlocked
at gasyncqueue.c line 422
#3 g_async_queue_timeout_pop
at gasyncqueue.c line 543
#4 g_thread_pool_wait_for_new_pool
at gthreadpool.c line 167
#5 g_thread_pool_thread_proxy
at gthreadpool.c line 364
#6 g_thread_proxy
at gthread.c line 784
#7 start_thread
#8 clone

Thread 1 (Thread 0x7fbeaf7e1180 (LWP 1517))

#0 malloc_consolidate
#1 _int_malloc
#2 calloc
#3 open_memstream
#4 __vsyslog_chk
#5 __syslog_chk
#6 g_logv
at gmessages.c line 1341
#7 g_log
at gmessages.c line 1403
#8 g_return_if_fail_warning
at gmessages.c line 2702
#9 g_variant_builder_add_value
at gvariant.c line 3486
#10 g_variant_builder_add
at gvariant.c line 5531
#11 g_dbus_message_to_blob
at gdbusmessage.c line 2670
#12 g_dbus_connection_send_message_unlocked
at gdbusconnection.c line 1617
#13 g_dbus_connection_send_message
at gdbusconnection.c line 1731
#14 invoke_get_property_in_idle_cb
at gdbusconnection.c line 4148
#15 g_main_dispatch
at gmain.c line 3148
#16 g_main_context_dispatch
at gmain.c line 3813
#17 g_main_context_iterate
at gmain.c line 3886
#18 g_main_loop_run
at gmain.c line 4082
#19 main
at main.c line 404

        ret = 1
        res = <optimized out>
        do_timed_exit = 0
        print_version = 0
        fatal_warnings = 0
        entries = 
            {{long_name = 0xaab7893ee9 "fatal-warnings", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0xaab7ab4194 <fatal_warnings>, description = 0xaab7893ef8 "Make all warnings fatal", arg_description = 0x0}, {long_name = 0xaab7893f10 "timed-exit", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0xaab7ab4190 <do_timed_exit>, description = 0xaab7894110 "Exit after a time (for debugging)", arg_description = 0x0}, {long_name = 0xaab7893f25 "version", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0xaab7ab4198 <print_version>, description = 0xaab7893f1b "Print GDM version", arg_description = 0x0}, {long_name = 0x0, short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x0, description = 0x0, arg_description = 0x0}}

Comment 1 Hussam Al-Tayeb 2017-08-23 11:24:46 UTC

Created attachment 358228 [details]
valgrind log.

I was able to get a valgrind log with assistance in #Gnome-shell irc channel (that you very much for that).

Comment 2 Ray Strode [halfline] 2017-08-23 13:34:11 UTC

Created attachment 358237 [details] [review]
manager: fix dangling pointer free

When reauthenticating, we can crash if configured with
--disable-user-display-server and a non-login screen session
unlocks the screen due to a dangling pointer.

This commit fixes that.

Comment 3 Ray Strode [halfline] 2017-08-23 13:36:39 UTC

Attachment 358237 [details] pushed as 42ae130 - manager: fix dangling pointer free