[Mono-list] Frequent segfaults in c# running on mono

River Satya river.satya at gmail.com
Fri Nov 27 12:32:32 UTC 2015 

Any idea if it's been fixed again in 4.2?

On 27 November 2015 at 23:26, River Satya <river.satya at gmail.com> wrote:

> Ah, of course, thank-you!! We had seen this in the past but not for a
> while now. It resurfaced when we moved to a new instance, which still had
> the old kernel. D'oh. Super unfortunate that this appears to be back in 4.1
> :(.
>
> On 27 November 2015 at 23:10, Matt Calder <mvcalder at gmail.com> wrote:
>
>> River,
>>
>> We see seg-faults in multi-threaded code on Ubuntu 14.04 and 14.10. These
>> can be reproduced relatively easily. We believe it is this bug:
>>
>> https://bugzilla.xamarin.com/show_bug.cgi?id=29692
>>
>> The discussions there will lead you to some discussions about kernel
>> versions. We still see this bug using 3.13 or 3.19 kernels.
>>
>> Matt
>>
>>
>> On Fri, Nov 27, 2015 at 5:31 AM, River Satya <river.satya at gmail.com>
>> wrote:
>>
>>>
>>>  Stack trace flavour 3:
>>>
>>> --
>>> :Stacktrace:
>>> -
>>> -  at <unknown> <0xffffffff>
>>> -  at (wrapper managed-to-native)
>>> System.Delegate.CreateDelegate_internal
>>> (System.Type,object,System.Reflection.MethodInfo,bool) <IL 0x00010,
>>> 0xffffffff>
>>> -  at System.Delegate.CreateDelegate
>>> (System.Type,object,System.Reflection.MethodInfo,bool,bool) <0x0071a>
>>> -  at System.Delegate.CreateDelegate
>>> (System.Type,object,System.Reflection.MethodInfo) <0x00021>
>>> -  at System.Reflection.Emit.DynamicMethod.CreateDelegate
>>> (System.Type,object) <0x00043>
>>> -  at System.Linq.Expressions.Compiler.LambdaCompiler.CreateDelegate ()
>>> <IL 0x00022, 0x00094>
>>> -  at System.Linq.Expressions.Compiler.LambdaCompiler.Compile
>>> (System.Linq.Expressions.LambdaExpression,System.Runtime.CompilerServices.DebugInfoGenerator)
>>> <IL 0x0001e, 0x000d6>
>>> -  at System.Linq.Expressions.Expression`1.Compile () <IL 0x00002,
>>> 0x00016>
>>> -  at ServiceStack.OrmLite.SqlExpressionVisitor`1.VisitMemberAccess
>>> (System.Linq.Expressions.MemberExpression) <IL 0x000fe, 0x003a6>
>>> -  at ServiceStack.OrmLite.SqlExpressionVisitor`1.Visit
>>> (System.Linq.Expressions.Expression) <IL 0x000e3, 0x000e1>
>>> -  at ServiceStack.OrmLite.SqlExpressionVisitor`1.VisitBinary
>>> (System.Linq.Expressions.BinaryExpression) <IL 0x0016d, 0x00736>
>>> -  at ServiceStack.OrmLite.SqlExpressionVisitor`1.Visit
>>> (System.Linq.Expressions.Expression) <IL 0x000fd, 0x0016b>
>>> -  at ServiceStack.OrmLite.SqlExpressionVisitor`1.VisitLambda
>>> (System.Linq.Expressions.LambdaExpression) <IL 0x0005a, 0x00169>
>>> -  at ServiceStack.OrmLite.SqlExpressionVisitor`1.Visit
>>> (System.Linq.Expressions.Expression) <IL 0x000d6, 0x0009c>
>>> -  at
>>> ServiceStack.OrmLite.SqlExpressionVisitor`1.ProcessInternalExpression ()
>>> <IL 0x0001a, 0x00073>
>>> -  at ServiceStack.OrmLite.SqlExpressionVisitor`1.And
>>> (System.Linq.Expressions.Expression`1<System.Func`2<T, bool>>) <IL 0x00027,
>>> 0x000f4>
>>> -  at ServiceStack.OrmLite.SqlExpressionVisitor`1.Where
>>> (System.Linq.Expressions.Expression`1<System.Func`2<T, bool>>) <IL 0x00005,
>>> 0x00028>
>>> -  at ServiceStack.OrmLite.ReadExtensions.Select<T>
>>> (System.Data.IDbCommand,System.Linq.Expressions.Expression`1<System.Func`2<T,
>>> bool>>) <IL 0x0000d, 0x0006e>
>>> -  at
>>> ServiceStack.OrmLite.ReadConnectionExtensions/<>c__DisplayClassd`1.<Select>b__c
>>> (System.Data.IDbCommand) <IL 0x00007, 0x00046>
>>> --
>>> :Native stacktrace:
>>> -
>>> -       /usr/bin/mono() [0x4b23dc]
>>> -       /lib/x86_64-linux-gnu/libpthread.so.0(+0x10340) [0x7fc516460340]
>>> -       /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x39) [0x7fc5160c1cc9]
>>> -       /lib/x86_64-linux-gnu/libc.so.6(abort+0x148) [0x7fc5160c50d8]
>>> -       /usr/bin/mono() [0x629999]
>>> -       /usr/bin/mono() [0x629ba7]
>>> -       /usr/bin/mono() [0x629cf6]
>>> -       /usr/bin/mono(mono_class_from_mono_type+0x37) [0x519b07]
>>> -       /usr/bin/mono() [0x42a69a]
>>> -       /usr/bin/mono() [0x42b301]
>>> -       /usr/bin/mono() [0x42c89f]
>>> -       /usr/bin/mono() [0x42d29b]
>>> -       /usr/bin/mono() [0x5398f8]
>>> -       [0x4115956d]
>>> -
>>> -Debug info from gdb:
>>> -
>>> -Could not attach to process.  If your uid matches the uid of the target
>>> -process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try
>>> --
>>>
>>>
>>> Stack trace flavour 4 (no non-native stacktrace):
>>> These vary a bit, but look pretty much like the below.
>>>
>>> --
>>> :Stacktrace:
>>> -
>>> -
>>> :Native stacktrace:
>>> -
>>> -       /usr/bin/mono() [0x4b23dc]
>>> -       /lib/x86_64-linux-gnu/libpthread.so.0(+0x10340) [0x7fb78e49c340]
>>> -       /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x39) [0x7fb78e0fdcc9]
>>> -       /lib/x86_64-linux-gnu/libc.so.6(abort+0x148) [0x7fb78e1010d8]
>>> -       /usr/bin/mono() [0x629999]
>>> -       /usr/bin/mono() [0x629ba7]
>>> -       /usr/bin/mono() [0x629cf6]
>>> -       /usr/bin/mono() [0x6194dc]
>>> -       /usr/bin/mono() [0x422086]
>>> -       /usr/bin/mono() [0x5a7012]
>>> -       /usr/bin/mono() [0x5b0720]
>>> -       /usr/bin/mono() [0x5a1d99]
>>> -       /usr/bin/mono() [0x5a1dd0]
>>> -       /usr/bin/mono() [0x5a226d]
>>> -       /usr/bin/mono() [0x5875f8]
>>> -       /usr/bin/mono() [0x623b66]
>>> -       /lib/x86_64-linux-gnu/libpthread.so.0(+0x8182) [0x7fb78e494182]
>>> -       /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d) [0x7fb78e1c147d]
>>> -
>>>
>>> On 27 November 2015 at 20:31, River Satya <river.satya at gmail.com> wrote:
>>>
>>>> Hi mono list,
>>>>
>>>> We see a lot of segfaults (~10 / day) in our program running on Ubuntu
>>>> Wheezy. I was hoping that upgrading to mono 4.2 would resolve it, but we're
>>>> still seeing them.
>>>>
>>>> The stack traces take a few different forms, so it's possible that
>>>> they're actually separate issues.
>>>>
>>>> We mostly see #1 and #4. #2 and #3 have only been seen in isolation,
>>>> but have more interesting stack traces.
>>>>
>>>> These look to me like mono bugs. Are any of these known issues? Is
>>>> there anything I can do to either work around them and/or assist in
>>>> debugging them? They're currently causing significant problems in a mission
>>>> critical piece of software for my client.
>>>>
>>>> (email split into pieces as the full version was rejected by the
>>>> maillist server).
>>>>
>>>> Thanks,
>>>>
>>>> River
>>>>
>>>>>
>>>>> Stack trace 1 (empty trace):
>>>>> :Stacktrace:
>>>>> -
>>>>> -
>>>>> :Native stacktrace:
>>>>> -
>>>>> Stack trace 2:
>>>>> --
>>>>> :Stacktrace:
>>>>> -
>>>>> -  at <unknown> <0xffffffff>
>>>>> -  at (wrapper managed-to-native)
>>>>> object.__icall_wrapper_mono_gc_alloc_vector (intptr,intptr,intptr) <IL
>>>>> 0x0000f, 0xffffffff>
>>>>> -  at (wrapper alloc) object.AllocVector (intptr,intptr) <IL 0x00088,
>>>>> 0xffffffff>
>>>>> -  at System.Xml.XmlUtf8RawTextWriter..ctor
>>>>> (System.IO.Stream,System.Xml.XmlWriterSettings) <IL 0x00039, 0x000cf>
>>>>> -  at System.Xml.XmlWriterSettings.CreateWriter (System.IO.Stream) <IL
>>>>> 0x00067, 0x00117>
>>>>> -  at System.Xml.XmlWriter.Create
>>>>> (System.IO.Stream,System.Xml.XmlWriterSettings) <IL 0x0000f, 0x00066>
>>>>> -  at
>>>>>  <snip> rest of stack trace is in our code</snip>
>>>>> --
>>>>> :Native stacktrace:
>>>>> -
>>>>> -       /usr/bin/mono() [0x49cf0c]
>>>>> -       /lib/x86_64-linux-gnu/libpthread.so.0(+0x10340)
>>>>> [0x7fb9e29e9340]
>>>>> -       /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x39) [0x7fb9e264acc9]
>>>>> -       /lib/x86_64-linux-gnu/libc.so.6(abort+0x148) [0x7fb9e264e0d8]
>>>>> -       /usr/bin/mono() [0x62a329]
>>>>> -       /usr/bin/mono() [0x62a537]
>>>>> -       /usr/bin/mono() [0x62a5e2]
>>>>> -       /usr/bin/mono() [0x5ea7a6]
>>>>> -       /usr/bin/mono() [0x5ecfe0]
>>>>> -       /usr/bin/mono() [0x5f5af2]
>>>>> -       /usr/bin/mono() [0x5f67aa]
>>>>> -       /usr/bin/mono() [0x5ecb03]
>>>>> -       /usr/bin/mono() [0x5dbf76]
>>>>> -       /usr/bin/mono() [0x5e380d]
>>>>> -       /usr/bin/mono() [0x5f99f8]
>>>>> -       /usr/bin/mono() [0x5e5f63]
>>>>> -       /usr/bin/mono() [0x5e805f]
>>>>> -       /usr/bin/mono() [0x5db55d]
>>>>> -       /usr/bin/mono() [0x5ca11e]
>>>>> --
>>>>
>>>>
>>>>
>>>>
>>>
>>> _______________________________________________
>>> Mono-list maillist  -  Mono-list at lists.ximian.com
>>> http://lists.ximian.com/mailman/listinfo/mono-list
>>>
>>>
>>
>
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