Bug 119620 – [Curl] Crash when starting second download.

• Status: RESOLVED
• Resolution: FIXED
• Component: WebCore Misc.

When I start a second download, I sometimes get a crash in Curl.
This happens because the Curl easy handle is deleted and removed from the Curl multi handle twice.
The first delete happens when the download thread has finished downloading,
and the second happens when the WebDownload object is deleted, and calls the cancel method.
The Curl handle is then put in a delete queue, which is processed by the download thread the next time it starts.
This is the reason the crash happens when the second download is started.

Created attachment 208419 [details]
Patch

[Brent Fulgham]

Comment on attachment 208419 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=208419&action=review

r=me

> Source/WebCore/platform/network/curl/CurlDownload.cpp:133
> +        if (addToCurl(m_pendingHandleList[0]))

I know you only moved this code, but glancing at it I am concerned by this loop. It seems like we could get stuck here if the 'addToCurl' keeps failing for the 0th entry in the pending handle list. Could you look over addToCurl at some point and see if this might be an issue?

[WebKit Commit Bot]

Comment on attachment 208419 [details]
Patch

Clearing flags on attachment: 208419

Committed r153944: <http://trac.webkit.org/changeset/153944>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

(In reply to comment #2)
> (From update of attachment 208419 [details])
> View in context: https://bugs.webkit.org/attachment.cgi?id=208419&action=review
> 
> r=me
> 

Thanks for reviewing, now I can download several files without crashing ;)

> > Source/WebCore/platform/network/curl/CurlDownload.cpp:133
> > +        if (addToCurl(m_pendingHandleList[0]))
> 
> I know you only moved this code, but glancing at it I am concerned by this loop. It seems like we could get stuck here if the 'addToCurl' keeps failing for the 0th entry in the pending handle list. Could you look over addToCurl at some point and see if this might be an issue?

Good point, will have a look.