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Posted to issues@trafficserver.apache.org by "Steve Jiang (JIRA)" <ji...@apache.org> on 2010/05/26 23:29:36 UTC
[jira] Created: (TS-377) InkFreeList and InkAtomicList are not
atomic in 64-bit
InkFreeList and InkAtomicList are not atomic in 64-bit
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Key: TS-377
URL: https://issues.apache.org/jira/browse/TS-377
Project: Traffic Server
Issue Type: Bug
Components: Core
Environment: x86_64
Reporter: Steve Jiang
The ABA problem may happen with the atomic operations when pointers are 64 bit.
In ink_queue.h,
typedef union {
struct {
void *pointer;
int32 version;
} s;
int64 data;
} head_p;
The s struct is > 8 bytes on 64-bit and version is supposed to prevent ABA. If INK_USE_MUTEX_FOR_FREELISTS is not defined the push and pop functions do a cas64 on the .data member, which will not check the version.
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[jira] Closed: (TS-377) InkFreeList and InkAtomicList are not
atomic in 64-bit
Posted by "Steve Jiang (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/TS-377?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Steve Jiang closed TS-377.
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Resolution: Invalid
My mistake, I was looking at an older version of the code. In trunk there are different macros for FREELIST_POINTER and FREELIST_VERSION that take advantage of address space on x86-64 being 48 bits.
> InkFreeList and InkAtomicList are not atomic in 64-bit
> ------------------------------------------------------
>
> Key: TS-377
> URL: https://issues.apache.org/jira/browse/TS-377
> Project: Traffic Server
> Issue Type: Bug
> Components: Core
> Environment: x86_64
> Reporter: Steve Jiang
>
> The ABA problem may happen with the atomic operations when pointers are 64 bit.
> In ink_queue.h,
> typedef union {
> struct {
> void *pointer;
> int32 version;
> } s;
> int64 data;
> } head_p;
> The s struct is > 8 bytes on 64-bit and version is supposed to prevent ABA. If INK_USE_MUTEX_FOR_FREELISTS is not defined the push and pop functions do a cas64 on the .data member, which will not check the version.
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