Imbus/xv6-riscv-kernel
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fix a potential kernel crash

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add a regression test for it
This commit is contained in:
Robert Morris 2019-09-20 09:41:03 -04:00
parent 57e40a0204
commit 402e7b5605
2 changed files with 17 additions and 1 deletions
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5
kernel/vm.c
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@ -99,6 +99,9 @@ walkaddr(pagetable_t pagetable, uint64 va)
pte_t *pte;
uint64 pa;
if(va >= MAXVA)
return 0;
pte = walk(pagetable, va, 0);
if(pte == 0)
return 0;
@ -408,7 +411,7 @@ copyinstr(pagetable_t pagetable, char *dst, uint64 srcva, uint64 max)
int got_null = 0;
while(got_null == 0 && max > 0){
va0 = (uint)PGROUNDDOWN(srcva);
va0 = PGROUNDDOWN(srcva);
pa0 = walkaddr(pagetable, va0);
if(pa0 == 0)
return -1;