Issues with debugging GC-related crashes #2

[kinke]

On Thursday, 19 April 2018 at 17:01:48 UTC, Matthias Klumpp wrote:
> Something that maybe is relevant though: I occasionally get the 
> following SIGABRT crash in the tool on machines which have the 
> SIGSEGV crash:
> ```
> Thread 53 "appstream-gener" received signal SIGABRT, Aborted.
> [Switching to Thread 0x7fdfe98d4700 (LWP 7326)]
> 0x00007ffff5040428 in __GI_raise (sig=sig at entry=6) at 
> ../sysdeps/unix/sysv/linux/raise.c:54
> 54      ../sysdeps/unix/sysv/linux/raise.c: No such file or 
> directory.
> (gdb) bt
> #0  0x00007ffff5040428 in __GI_raise (sig=sig at entry=6) at 
> ../sysdeps/unix/sysv/linux/raise.c:54
> #1  0x00007ffff504202a in __GI_abort () at abort.c:89
> #2  0x0000000000780ae0 in core.thread.Fiber.allocStack(ulong, 
> ulong) (this=0x7fde0758a680, guardPageSize=4096, sz=20480) at 
> src/core/thread.d:4606
> #3  0x00000000007807fc in 
> _D4core6thread5Fiber6__ctorMFNbDFZvmmZCQBlQBjQBf 
> (this=0x7fde0758a680, guardPageSize=4096, sz=16384, dg=...)
>     at src/core/thread.d:4134
> #4  0x00000000006f9b31 in 
> _D3std11concurrency__T9GeneratorTAyaZQp6__ctorMFDFZvZCQCaQBz__TQBpTQBiZQBx (this=0x7fde0758a680, dg=...)
>     at 
> /home/ubuntu/dtc/dmd/generated/linux/debug/64/../../../../../druntime/import/core/thread.d:4126
> #5  0x00000000006e9467 in 
> _D5asgen8handlers11iconhandler5Theme21matchingIconFilenamesMFAyaSQCl5utils9ImageSizebZC3std11concurrency__T9GeneratorTQCfZQp (this=0x7fdea2747800, relaxedScalingRules=true, size=..., iname=...) at ../src/asgen/handlers/iconhandler.d:196
> #6  0x00000000006ea75a in 
> _D5asgen8handlers11iconhandler11IconHandler21possibleIconFilenamesMFAyaSQCs5utils9ImageSizebZ9__lambda4MFZv (this=0x7fde0752bd00)
>     at ../src/asgen/handlers/iconhandler.d:392
> #7  0x000000000082fdfa in core.thread.Fiber.run() 
> (this=0x7fde07528580) at src/core/thread.d:4436
> #8  0x000000000082fd5d in fiber_entryPoint () at 
> src/core/thread.d:3665
> #9  0x0000000000000000 in  ()
> ```

You probably already figured that the new Fiber seems to be 
allocating its 16KB-stack, with an additional 4 KB guard page at 
its bottom, via a 20 KB mmap() call. The abort seems to be 
triggered by mprotect() returning -1, i.e., a failure to disallow 
all access to the the guard page; so checking `errno` should help.