Bug 44922 - Assertion at lock-free-alloc.c:457, condition `block_size == desc->block_size' not met
Summary: Assertion at lock-free-alloc.c:457, condition `block_size == desc->block_size...
Status: RESOLVED FIXED
Alias: None
Product: Runtime
Classification: Mono
Component: GC ()
Version: unspecified
Hardware: PC Mac OS
: --- major
Target Milestone: ---
Assignee: Vlad Brezae
URL:
Depends on:
Blocks:
 
Reported: 2016-09-30 11:05 UTC by Marek Safar
Modified: 2016-10-05 11:15 UTC (History)
4 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description Marek Safar 2016-09-30 11:05:55 UTC
Happens when using roslyn compiler.

One example

https://jenkins.mono-project.com/job/test-mono-pull-request-i386-osx/1269/consoleFull#-1856564418c04ca618-a109-447b-99e0-481aaedae630

* Assertion at lock-free-alloc.c:457, condition `block_size == desc->block_size' not met


Native stacktrace:

	0   mono                                0x001493a1 mono_handle_native_sigsegv + 353
	1   mono                                0x001a3541 sigabrt_signal_handler + 161
	2   libsystem_platform.dylib            0x9d46179b _sigtramp + 43
	3   ???                                 0xffffffff 0x0 + 4294967295
	4   libsystem_c.dylib                   0x92851c38 abort + 156
	5   mono                                0x00304478 mono_log_write_logfile + 376
	6   mono                                0x002ff052 structured_log_adapter + 50
	7   mono                                0x003203a4 monoeg_g_logv + 100
	8   mono                                0x003204fb monoeg_assertion_message + 43
	9   mono                                0x0030dde9 mono_lock_free_free + 745
	10  mono                                0x002cd280 sgen_free_internal_dynamic + 144
	11  mono                                0x002ce3ab sgen_los_scan_card_table + 411
	12  mono                                0x002cb117 job_mod_union_preclean + 87
	13  mono                                0x002ebd60 thread_func + 240
	14  libsystem_pthread.dylib             0x9e2b6780 _pthread_body + 138
	15  libsystem_pthread.dylib             0x9e2b66f6 _pthread_body + 0
	16  libsystem_pthread.dylib             0x9e2b3f7a thread_start + 34

Debug info from gdb:

(lldb) command source -s 0 '/tmp/mono-gdb-commands.YuODYi'
Executing commands in '/tmp/mono-gdb-commands.YuODYi'.
(lldb) process attach --pid 94341
error: attach failed: unable to attach

=================================================================
Got a SIGABRT while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries 
used by your application.
=================================================================
Comment 1 Marek Safar 2016-10-04 09:22:01 UTC
This is quite reliable when compiling mscorlib on linux

Trace from the assert

(gdb) bt
#0  mono_lock_free_free (ptr=0xf533f554, block_size=4096) at lock-free-alloc.c:457
#1  0x08342e1d in sgen_free_internal_dynamic (addr=0xf533f554, size=4096, type=32) at sgen-internal.c:206
#2  0x08343ec3 in sgen_los_scan_card_table (scan_type=scan_type@entry=CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx=...) at sgen-los.c:662
#3  0x0833b7eb in job_mod_union_preclean (worker_data_untyped=0xf7d6e004, job=0xf3f02cc4) at sgen-gc.c:1395
#4  0x0835b4d5 in thread_func (thread_data=0xf7d6e004) at sgen-thread-pool.c:117
#5  0xf7f67f70 in start_thread () from /lib/i386-linux-gnu/libpthread.so.0
#6  0xf7e9e70e in clone () from /lib/i386-linux-gnu/libc.so.6
(gdb) p *desc
Cannot access memory at address 0x0
(gdb) p *ptr
Attempt to dereference a generic pointer.
(gdb) p ptr
$2 = (gpointer) 0xf533f554
Comment 2 Bernhard Urban 2016-10-05 11:15:17 UTC
https://github.com/mono/mono/pull/3705