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unix/mpthreadport: Ensure enough thread stack to detect overflow.

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Following up to 5e6cee07ab, some systems (eg
FreeBSD 12.0 64-bit) will crash if the stack-overflow margin is too small.
It seems the margin of 8192 bytes (or thereabouts) is always needed.  This
commit adds this much margin if the requested stack size is too small.

Fixes issue #5824.
This commit is contained in:
Damien George 2020-03-28 22:39:01 +11:00
parent 581f9135a4
commit 8fff0b0acd
1 changed files with 9 additions and 6 deletions
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15
ports/unix/mpthreadport.c
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@ -47,6 +47,9 @@
#define MP_THREAD_GC_SIGNAL (SIGUSR1)
#endif
// This value seems to be about right for both 32-bit and 64-bit builds.
#define THREAD_STACK_OVERFLOW_MARGIN (8192)
// this structure forms a linked list, one node per active thread
typedef struct _thread_t {
pthread_t id; // system id of thread
@ -193,6 +196,11 @@ void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
*stack_size = PTHREAD_STACK_MIN;
}
// ensure there is enough stack to include a stack-overflow margin
if (*stack_size < 2 * THREAD_STACK_OVERFLOW_MARGIN) {
*stack_size = 2 * THREAD_STACK_OVERFLOW_MARGIN;
}
// set thread attributes
pthread_attr_t attr;
int ret = pthread_attr_init(&attr);
@ -220,12 +228,7 @@ void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
}
// adjust stack_size to provide room to recover from hitting the limit
// this value seems to be about right for both 32-bit and 64-bit builds
if (*stack_size >= 2 * 8192) {
*stack_size -= 8192;
} else {
*stack_size /= 2;
}
*stack_size -= THREAD_STACK_OVERFLOW_MARGIN;
// add thread to linked list of all threads
thread_t *th = malloc(sizeof(thread_t));