diff options
| author | Rick Hudson <rlh@golang.org> | 2014-10-23 15:51:17 -0400 |
|---|---|---|
| committer | Rick Hudson <rlh@golang.org> | 2014-10-23 15:51:17 -0400 |
| commit | 978c971bacf92ee97b8e24ce45b485afa1c31fad (patch) | |
| tree | eb027d60a93732edaf1aa1f4bb52c56304ed102b | |
| parent | 78db2eb9c66d478bee0d56edcc55d4f865f8c6c7 (diff) | |
| download | go-978c971bacf92ee97b8e24ce45b485afa1c31fad.tar.gz | |
[dev.garbage] runtime: simplifiy lfstack.c due to undiagnosed buffer corruption.
The changes got rid of the problems we were seeing.
We suspect the pushcnt field has a race.
LGTM=rsc
R=dvyukov, rsc
CC=golang-codereviews
https://codereview.appspot.com/159330043
Committer: Russ Cox <rsc@golang.org>
| -rw-r--r-- | src/runtime/lfstack.c | 14 | ||||
| -rw-r--r-- | src/runtime/runtime.h | 2 |
2 files changed, 7 insertions, 9 deletions
diff --git a/src/runtime/lfstack.c b/src/runtime/lfstack.c index 57e0af282..0ced839c2 100644 --- a/src/runtime/lfstack.c +++ b/src/runtime/lfstack.c @@ -46,7 +46,7 @@ runtime·lfstackpush(uint64 *head, LFNode *node) new = (uint64)(uintptr)node|(((uint64)node->pushcnt&CNT_MASK)<<PTR_BITS); for(;;) { old = runtime·atomicload64(head); - node->next = (LFNode*)(uintptr)(old&PTR_MASK); + node->next = old; if(runtime·cas64(head, old, new)) break; } @@ -55,19 +55,17 @@ runtime·lfstackpush(uint64 *head, LFNode *node) LFNode* runtime·lfstackpop(uint64 *head) { - LFNode *node, *node2; - uint64 old, new; + LFNode *node; + uint64 old, next; for(;;) { old = runtime·atomicload64(head); if(old == 0) return nil; node = (LFNode*)(uintptr)(old&PTR_MASK); - node2 = runtime·atomicloadp(&node->next); - new = 0; - if(node2 != nil) - new = (uint64)(uintptr)node2|(((uint64)node2->pushcnt&CNT_MASK)<<PTR_BITS); - if(runtime·cas64(head, old, new)) + next = runtime·atomicload64(&node->next); + + if(runtime·cas64(head, old, next)) return node; } } diff --git a/src/runtime/runtime.h b/src/runtime/runtime.h index bea773799..37929c59c 100644 --- a/src/runtime/runtime.h +++ b/src/runtime/runtime.h @@ -573,7 +573,7 @@ enum { // Lock-free stack node. struct LFNode { - LFNode *next; + uint64 next; uintptr pushcnt; }; |