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| author | Robert Morris <[email protected]> | 2019-07-01 17:46:06 -0400 |
|---|---|---|
| committer | Robert Morris <[email protected]> | 2019-07-01 17:46:06 -0400 |
| commit | abfe9999f447c15d904b3c11f32d4a22a45470a0 (patch) | |
| tree | bdcf8264c9da666661b107157a6c634b86608ee2 /kernel/vm.c | |
| parent | 18e76a6c47b0f62b2458430d4357f3eb68bfd759 (diff) | |
| download | xv6-labs-abfe9999f447c15d904b3c11f32d4a22a45470a0.tar.gz xv6-labs-abfe9999f447c15d904b3c11f32d4a22a45470a0.tar.bz2 xv6-labs-abfe9999f447c15d904b3c11f32d4a22a45470a0.zip | |
have fork() fail, not panic, if not enough phys mem
Diffstat (limited to 'kernel/vm.c')
| -rw-r--r-- | kernel/vm.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/vm.c b/kernel/vm.c index 580669f..7d67464 100644 --- a/kernel/vm.c +++ b/kernel/vm.c @@ -273,7 +273,9 @@ uvmfree(pagetable_t pagetable, uint64 sz) // its memory into a child's page table. // Copies both the page table and the // physical memory. -void +// returns 0 on success, -1 on failure. +// frees any allocated pages on failure. +int uvmcopy(pagetable_t old, pagetable_t new, uint64 sz) { pte_t *pte; @@ -289,10 +291,15 @@ uvmcopy(pagetable_t old, pagetable_t new, uint64 sz) pa = PTE2PA(*pte); flags = PTE_FLAGS(*pte); if((mem = kalloc()) == 0) - panic("uvmcopy: kalloc failed"); + goto err; memmove(mem, (char*)pa, PGSIZE); mappages(new, i, PGSIZE, (uint64)mem, flags); } + return 0; + + err: + unmappages(new, 0, i, 1); + return -1; } // Copy from kernel to user. |