After update to latest GCC 10, I see the aforementioned test failing. I use -flto that enables cross module inlining and I investigated that stack overflow detection does not work in `check_stack_overrun` function in sql_parse.cc. It's very likely caused by optimized out the allocation of buf argument of the function, which is a stack variable in a caller frame.
I'm suggesting the following patch:
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
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index a8e66d2a..9cbf23d7 100644
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--- a/sql/sql_parse.cc
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+++ b/sql/sql_parse.cc
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@@ -7229,10 +7229,14 @@ long max_stack_used;
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corresponding exec. (Thus we only have to check in fix_fields.)
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- Passing to check_stack_overrun() prevents the compiler from removing it.
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*/
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-bool check_stack_overrun(THD *thd, long margin,
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- uchar *buf __attribute__((unused)))
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+bool check_stack_overrun(THD *thd, long margin, uchar *buf)
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{
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long stack_used;
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+ /*
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+ Take address of the buf argument in order to prevent
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+ the stack allocation made this function caller.
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+ */
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+ static volatile uchar *buf_ptr = buf;
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DBUG_ASSERT(thd == current_thd);
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if ((stack_used= available_stack_size(thd->thread_stack, &stack_used)) >=
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(long) (my_thread_stack_size - margin))
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Bug
Major
