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use region quarantine even if MAP_FIXED call fails

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This is a more sensible way of handling an out-of-memory failure in this
edge case. It doesn't matter much in practice.
This commit is contained in:
Daniel Micay 2021-05-12 00:20:03 -04:00
parent 2335f56713
commit 5c974bdf82
2 changed files with 4 additions and 4 deletions
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2
README.md
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@ -1008,7 +1008,7 @@ System calls used by all build configurations:
* `mremap(old, old_size, new_size, MREMAP_MAYMOVE|MREMAP_FIXED, new)` * `mremap(old, old_size, new_size, MREMAP_MAYMOVE|MREMAP_FIXED, new)`
* `munmap` * `munmap`
* `write(STDERR_FILENO, buf, len)` (before aborting due to memory corruption) * `write(STDERR_FILENO, buf, len)` (before aborting due to memory corruption)
* `madvise(ptr, size, MADV_DONTNEED)` for `malloc_trim` with slab quarantines * `madvise(ptr, size, MADV_DONTNEED)`
The main distinction from a typical malloc implementation is the use of The main distinction from a typical malloc implementation is the use of
getrandom. A common compatibility issue is that existing system call whitelists getrandom. A common compatibility issue is that existing system call whitelists

6
h_malloc.c
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@ -839,10 +839,10 @@ static void regions_quarantine_deallocate_pages(void *p, size_t size, size_t gua
} }
if (unlikely(memory_map_fixed(p, size))) { if (unlikely(memory_map_fixed(p, size))) {
deallocate_pages(p, size, guard_size); memory_purge(p, size);
return; } else {
}
memory_set_name(p, size, "malloc large quarantine"); memory_set_name(p, size, "malloc large quarantine");
}
struct quarantine_info target = struct quarantine_info target =
(struct quarantine_info){(char *)p - guard_size, size + guard_size * 2}; (struct quarantine_info){(char *)p - guard_size, size + guard_size * 2};