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smp_topo(): make it idempotent

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If more than one call to the function occurs, it currently allocates the
same amount from the group[] array, eventually leading to the memory
corruption.

Noted and reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D39981
This commit is contained in:
Konstantin Belousov 2023-05-07 21:37:42 +03:00
parent 9801e7c275
commit d0f67f9757
1 changed files with 8 additions and 1 deletions
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9
sys/kern/subr_smp.c
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@ -645,7 +645,14 @@ struct cpu_group *
smp_topo(void)
{
char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ];
struct cpu_group *top;
static struct cpu_group *top = NULL;
/*
* The first call to smp_topo() is guaranteed to occur
* during the kernel boot while we are still single-threaded.
*/
if (top != NULL)
return (top);
/*
* Check for a fake topology request for debugging purposes.