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| author | Austin Clements <austin@google.com> | 2015-11-15 23:09:16 -0500 |
|---|---|---|
| committer | Austin Clements <austin@google.com> | 2015-11-17 02:25:04 +0000 |
| commit | e49330911f52bcb2aeb7eae4ca6df4fc8a013abe (patch) | |
| tree | dc301867041e7f62c00de549648e977703f105e6 | |
| parent | 20a053611b2ac6cdd760fd3d391e4f7ae2d72a77 (diff) | |
| download | go-e49330911f52bcb2aeb7eae4ca6df4fc8a013abe.tar.gz go-e49330911f52bcb2aeb7eae4ca6df4fc8a013abe.zip | |
[release-branch.go1.5] runtime: avoid stat underflow crash
If the area returned by sysReserve in mheap.sysAlloc is outside the
usable arena, we sysFree it. We pass a fake stat pointer to sysFree
because we haven't added the allocation to any stat at that point.
However, we pass a 0 stat, so sysFree panics when it decrements the
stat because the fake stat underflows.
Fix this by setting the fake stat to the allocation size.
Updates #13143 (this is a prerequisite to fixing that bug).
Change-Id: I61a6c9be19ac1c95863cf6a8435e19790c8bfc9a
Reviewed-on: https://go-review.googlesource.com/16926
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-on: https://go-review.googlesource.com/16987
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
| -rw-r--r-- | src/runtime/malloc.go | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/src/runtime/malloc.go b/src/runtime/malloc.go index 353f84083f..a8a5d48b5d 100644 --- a/src/runtime/malloc.go +++ b/src/runtime/malloc.go @@ -411,7 +411,10 @@ func mHeap_SysAlloc(h *mheap, n uintptr) unsafe.Pointer { h.arena_used = used h.arena_reserved = reserved } else { - var stat uint64 + // We haven't added this allocation to + // the stats, so subtract it from a + // fake stat (but avoid underflow). + stat := uint64(p_size) sysFree((unsafe.Pointer)(p), p_size, &stat) } } |