[Mono-dev] SIGSEGV from bad generic type (bug 30085)

Miguel de Icaza miguel at xamarin.com
Thu May 28 20:29:26 UTC 2015


There is already a similar pull request.

The issue is that returning NULL there has a slightly different meaning.
So the complete fix is to restructure some of the code.



On Thu, May 28, 2015 at 4:25 PM, David Curylo <curylod at asme.org> wrote:

> Found the issue and created PR 1839:
> https://github.com/mono/mono/pull/1839
> Please take a look and let me know if you have any concerns with the fix.
> Thanks,
> Dave
> On May 28, 2015, at 3:51 PM, David Curylo <curylod at asme.org> wrote:
> I’m researching an issue reported by a colleague of mine.  The error is
> rather serious as the use of a bad type name causes a native SIGSEGV and
> kills the runtime, when it really should just return a null because it
> can’t find the type.  This code reproduces the issue:
> System.Type.GetType("System.Nullable`1[[System.Int32, mscorlibBAD]]")
> Since I see there is some work going on with System.Type, I was hopeful
> that mono master would no longer have this issue, but it still exists.
> This is what I’m getting in the thread dump when this occurs and the root
> cause appears to be somewhere in _mono_reflection_get_type_from_info.  Any
> ideas what may be the root cause here?
> Thread 1 (Thread 0x7f28ae81f7c0 (LWP 76562)):
> #0  0x00007f28adcf7ee9 in __libc_waitpid (pid=pid at entry=76565,
> stat_loc=stat_loc at entry=0x7f28ae82919c, options=options at entry=0) at
> ../sysdeps/unix/sysv/linux/waitpid.c:40
> #1  0x00000000004a2015 in mono_handle_native_sigsegv (signal=signal at entry=11,
> ctx=ctx at entry=0x7f28ae829ac0, info=info at entry=0x7f28ae829bf0) at
> mini-exceptions.c:2226
> #2  0x00000000004f782e in mono_arch_handle_altstack_exception
> (sigctx=sigctx at entry=0x7f28ae829ac0, siginfo=siginfo at entry=0x7f28ae829bf0,
> fault_addr=<optimized out>, stack_ovf=stack_ovf at entry=0) at
> exceptions-amd64.c:858
> #3  0x0000000000422f28 in mono_sigsegv_signal_handler (_dummy=11,
> _info=0x7f28ae829bf0, context=0x7f28ae829ac0) at mini-runtime.c:2526
> #4  <signal handler called>
> *#5  0x00000000005bcb91 in _mono_reflection_get_type_from_info
> (info=0x1efb270, image=image at entry=0x0, ignorecase=ignorecase at entry=0) at
> reflection.c:7450*
> #6  0x00000000005bc750 in mono_reflection_get_type_internal
> (rootimage=rootimage at entry=0x0, image=<optimized out>, info=info at entry=0x7fff8b7388e0,
> ignorecase=ignorecase at entry=0) at reflection.c:7565
> #7  0x00000000005bc9b3 in mono_reflection_get_type_with_rootimage
> (rootimage=rootimage at entry=0x0, image=image at entry=0x0, info=info at entry=0x7fff8b7388e0,
> ignorecase=ignorecase at entry=0, type_resolve=type_resolve at entry=0x7fff8b7388d4)
> at reflection.c:7661
> #8  0x00000000005bcb00 in mono_reflection_get_type (image=image at entry=0x0,
> info=info at entry=0x7fff8b7388e0, ignorecase=ignorecase at entry=0,
> type_resolve=type_resolve at entry=0x7fff8b7388d4) at reflection.c:7613
> #9  0x000000000053456d in type_from_name (ignoreCase=<optimized out>,
> str=0x1ef44f0 "System.Nullable`1[[System.Int32, mscorlibBAD]]") at
> icall.c:1286
> #10 ves_icall_type_from_name (name=0x7f28ae7981b0, throwOnError=<optimized
> out>, ignoreCase=<optimized out>) at icall.c:1322
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