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Merge pull request #2647 from citusdata/fix_alloca_bug 

Ensure that stack resizing logic works expected
pull/2650/head
Önder Kalacı 2019-04-03 12:24:14 +02:00 committed by GitHub
parent 4a982358a6 fb38dc3136
commit 87db7a7578
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1 changed files with 18 additions and 0 deletions
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18
src/backend/distributed/shared_library_init.c
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@ -52,6 +52,7 @@
#include "distributed/worker_manager.h" #include "distributed/worker_manager.h"
#include "distributed/worker_protocol.h" #include "distributed/worker_protocol.h"
#include "distributed/worker_shard_visibility.h" #include "distributed/worker_shard_visibility.h"
#include "port/atomics.h"
#include "postmaster/postmaster.h" #include "postmaster/postmaster.h"
#include "optimizer/planner.h" #include "optimizer/planner.h"
#include "optimizer/paths.h" #include "optimizer/paths.h"
@ -261,7 +262,24 @@ ResizeStackToMaximumDepth(void)
long max_stack_depth_bytes = max_stack_depth * 1024L; long max_stack_depth_bytes = max_stack_depth * 1024L;
stack_resizer = alloca(max_stack_depth_bytes); stack_resizer = alloca(max_stack_depth_bytes);
/*
* Different architectures might have different directions while
* growing the stack. So, touch both ends.
*/
stack_resizer[0] = 0;
stack_resizer[max_stack_depth_bytes - 1] = 0; stack_resizer[max_stack_depth_bytes - 1] = 0;
/*
* Passing the address to external function also prevents the function
* from being optimized away, and the debug elog can also help with
* diagnosis if needed.
*/
elog(DEBUG5, "entry stack is at %p, increased to %p, the top and bottom values of "
"the stack is %d and %d", &stack_resizer[0],
&stack_resizer[max_stack_depth_bytes - 1],
stack_resizer[max_stack_depth_bytes - 1], stack_resizer[0]);
#endif #endif
} }