mem: implement a stack overflow detection mechanism #293
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enable-stack-overflow-check is a configuration option to enable stack overflow check.
ABTI_mem_register_stack() and ABTI_mem_unregister_stack() are functions to register and unregister a stack. Currently only Valgrind uses these functions, but they will be used to insert and check a stack canary value.
A stack canary is a special value that is written at the bottom of the ULT stack. The Argobots runtime can detect if this value is overwritten by stack overflow when a stack is freed. This mechanism does not catch stack overflow when it happens, but this is a quick method to check if there is no stack overflow. This option is disabled by default. It can be enabled by setting --enable-stack-overflow-check=canary-XX where XX is the canary size.
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Problems
With Argobots, stack overflow can easily happen because each stack tends to be small (e.g., #274), but this overflow is often silent because there is no stack guard page. Creating an
mprotect()-ed stack is not very trivial, but at least Argobots should employ a simple mechanism to detect it.Solution
This patch implements a stack canary that can check whether a stack overflow happens or not when a ULT is freed. This check is quite simple and lightweight. If stack overflow is detected, the runtime terminates. Please check the mechanism here: https://en.wikipedia.org/wiki/Stack_buffer_overflow#Stack_canaries
Note that this mechanism is to make sure that there is no stack overflow. This mechanism cannot pinpoint where the stack overflow happens.
This mechanism slightly degrades the performance, so it is disabled by default. It can be enabled by setting
--enable-stack-overflow-check=canary(or--enable-stack-overflow-check=canary-XXwhere XX is a large number to use a larger canary) at configuration time.Impact
This feature is disabled by default, so it will not affect the default behavior.