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scudo: Preserve no-memtag attribute on cached secondary allocations. 

Differential Revision: https://reviews.llvm.org/D99103
This commit is contained in:
Peter Collingbourne 2021-03-22 12:29:51 -07:00
parent 5f1de9cab1
commit e702fd4f1b
1 changed files with 22 additions and 16 deletions
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38
compiler-rt/lib/scudo/standalone/secondary.h
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@ -86,6 +86,25 @@ public:
static const uptr MaxUnusedCachePages = 4U;
template <typename Config>
void mapSecondary(Options Options, uptr CommitBase, uptr CommitSize,
uptr AllocPos, uptr Flags, MapPlatformData *Data) {
const uptr MaxUnusedCacheBytes = MaxUnusedCachePages * getPageSizeCached();
if (useMemoryTagging<Config>(Options) && CommitSize > MaxUnusedCacheBytes) {
const uptr UntaggedPos = Max(AllocPos, CommitBase + MaxUnusedCacheBytes);
map(reinterpret_cast<void *>(CommitBase), UntaggedPos - CommitBase,
"scudo:secondary", MAP_RESIZABLE | MAP_MEMTAG | Flags, Data);
map(reinterpret_cast<void *>(UntaggedPos),
CommitBase + CommitSize - UntaggedPos, "scudo:secondary",
MAP_RESIZABLE | Flags, Data);
} else {
map(reinterpret_cast<void *>(CommitBase), CommitSize, "scudo:secondary",
MAP_RESIZABLE | (useMemoryTagging<Config>(Options) ? MAP_MEMTAG : 0) |
Flags,
Data);
}
}
template <typename Config> class MapAllocatorCache {
public:
// Ensure the default maximum specified fits the array.
@ -129,9 +148,8 @@ public:
// Fuchsia does not support replacing mappings by creating a new mapping
// on top so we just do the two syscalls there.
Entry.Time = 0;
map(reinterpret_cast<void *>(Entry.CommitBase), Entry.CommitSize,
"scudo:secondary", MAP_RESIZABLE | MAP_NOACCESS | MAP_MEMTAG,
&Entry.Data);
mapSecondary<Config>(Options, Entry.CommitBase, Entry.CommitSize,
Entry.CommitBase, MAP_NOACCESS, &Entry.Data);
} else {
setMemoryPermission(Entry.CommitBase, Entry.CommitSize, MAP_NOACCESS,
&Entry.Data);
@ -530,19 +548,7 @@ void *MapAllocator<Config>::allocate(Options Options, uptr Size, uptr Alignment,
const uptr CommitSize = MapEnd - PageSize - CommitBase;
const uptr AllocPos = roundDownTo(CommitBase + CommitSize - Size, Alignment);
const uptr MaxUnusedCacheBytes = MaxUnusedCachePages * getPageSizeCached();
if (useMemoryTagging<Config>(Options) && CommitSize > MaxUnusedCacheBytes) {
const uptr UntaggedPos = Max(AllocPos, CommitBase + MaxUnusedCacheBytes);
map(reinterpret_cast<void *>(CommitBase), UntaggedPos - CommitBase,
"scudo:secondary", MAP_RESIZABLE | MAP_MEMTAG, &Data);
map(reinterpret_cast<void *>(UntaggedPos),
CommitBase + CommitSize - UntaggedPos, "scudo:secondary", MAP_RESIZABLE,
&Data);
} else {
map(reinterpret_cast<void *>(CommitBase), CommitSize, "scudo:secondary",
MAP_RESIZABLE | (useMemoryTagging<Config>(Options) ? MAP_MEMTAG : 0),
&Data);
}
mapSecondary<Config>(Options, CommitBase, CommitSize, AllocPos, 0, &Data);
const uptr HeaderPos =
AllocPos - Chunk::getHeaderSize() - LargeBlock::getHeaderSize();
LargeBlock::Header *H = reinterpret_cast<LargeBlock::Header *>(