534655 - GCHeap incorrectly handling return from VMPI_reserve

Status: RESOLVED FIXED

(Tamarin Graveyard :: Garbage Collection (mmGC), defect, P2)

Description

[Brent Getlin]

User-Agent:       Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30729)
Build Identifier: 

Since the input address to VMPI_Reserve is merely a "hint" at which address to reserve, it may not actually reserve the exact region that we're asking for.  Therefore we need to make sure the returned region is the same as the "asked for" region before assuming the new block is contiguous.

Reproducible: Sometimes

Comment 1

[Brent Getlin]

Attachment: Patch

Comment 2

[Lars T Hansen]

Brent reports that this is crashy, will hold off on review until that is resolved.

Comment 3

[Felix S. Klock II [:pnkfelix, :fklock]]

(In reply to comment #2)
> Brent reports that this is crashy, will hold off on review until that is
> resolved.

Further info: Brent reports to me that his memory is that after checking in this fix, the Linux smoke builds started crashing intermittently approximately 50% of the time.

Comment 4

[Felix S. Klock II [:pnkfelix, :fklock]]

(In reply to comment #1)
> Created attachment 417497 [details] [diff] [review] [review]
> Patch

Looks to me like something very much like this patch was already committed in changeset:3459:

  http://hg.mozilla.org/tamarin-redux/rev/5bcf95ed4a0a

(I feel like I'm taking crazy pills; how did I not notice this before?  Did I simply not attempt to apply the patch?)

Comment 5

[Felix S. Klock II [:pnkfelix, :fklock]]

Fixed by changeset:3459 as noted in comment 4.