Messages in this thread | | | Date | Fri, 29 Sep 2006 09:05:57 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: How is Code in do_sys_settimeofday() safe in case of SMP and Nest Kernel Path? |
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On Fri, 29 Sep 2006, Dong Feng wrote:
> For my understanding, an assignment between structs should be a > bit-wise copy. Such operation is not atomic, so it can not be supposed
Byte or Machine word yes.
> SMP-safe. And the subsequent test-and-assign operation on firsttime is > not atomic, either.
No its not atomic on its own. Correct.
> If the comments mean the subsequent code is SMP-safe and can prevent > nest-kernel-path, how does it achieves that?
It relies on locking outside of do_sys_settimeofday(). Seems that this indicates locking is to be performed by the arch before calling do_sys_settimeofday. Looks suspicious to me. Check that this function is always called with the same lock. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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