Not thread-safe: C++ Exception Processing Crashes in GNU Arm Embedded Toolchain
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
GNU Arm Embedded Toolchain |
New
|
Undecided
|
Unassigned |
Bug Description
Concurrently throwing C++ exceptions in multiple threads crashes.
This bug has impacted multiple commercial projects, some examples:
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BACKGROUND
Exception unwinding requires some data structures; specifically
the libgcc module unwind-dw2-fde.c has two-three statics.
These statics are protected by a gthread_mutex.
BUG
Arm build of libgcc builds gthread_mutex as no-op.
Thus applications cannot provide for example an RTOS
mutex with priority inheritance to protect above statics.
If I understand correctly, ARM toolchain build includes:
gthr-single.h
which dummies out the gthread functions as inline no-ops;
consequently they cannot be overridden.
SUGGESTIONS
A couple different approaches to fix this:
1) Create+use a separate gthreads module to provide weak
no-op functions for the gthreads functions. Thus RTOS users
can provide an alternate implementation of gthreads
appropriate for their RTOS, and non-RTOS users are
unaffected.
2) Use thread-local storage instead of statics in unwind-dw2-fde.c?
Is there a architecture-
Please let me know if you agree, and if I can help...
Thanks!
Best Regards, Dave
description: | updated |
description: | updated |
summary: |
- Not thread-safe: C++ Exception Processing in GNU Arm Embedded Toolchain + Not thread-safe: C++ Exception Processing Crashes in GNU Arm Embedded + Toolchain |
I'm hitting this same issue using FreeRTOS on a single core MCU.
Any ideas on if this is possible to work around with a GCC wrap linker option perhaps?