Re: assertion "p >= path" failed

[Tim Adye <T.J.Adye@rl.ac.uk>]

Hi Ken,

On 11/12/2019 16:03, Ken Brown wrote:
> On 11/4/2019 7:49 AM, Tim Adye wrote:
>> Hi Ken,
>>
>> On 31/10/2019 18:19, Ken Brown wrote:
>>> [Please don't top-post on this list.  Thanks.]
>>>
>>> On 10/30/2019 7:56 PM, Tim Adye wrote:
>>>> I'm afraid I get a very similar error with 3.1.0-0.7:
>>>>
>>>> assertion "p >= path" failed: file
>>>> "/home/kbrown/src/cygpackages/cygwin/cygwin-3.1.0-0.7.x86_64/src/newlib-cygwin/winsup/cygwin/path.cc",
>>>>
>>>> line 2906, function: int symlink_info::check(char*, const suffix_info*,
>>>> fs_info&, path_conv_handle&)
>>> OK, so your issue is different from the one that was fixed.
>>>
>>>> Again following resume from hibernation after going offline with the offline
>>>> files as HOME (H:\).
>>> I'm not familiar with offline files, so it would help if you would explain this
>>> in complete detail.
>> Offline Files is a feature of Sync Center that makes network files available to
>> a user, even if the network connection to the server is unavailable. Windows
>> keeps a copy of files stored on the network on the local computer. This allows
>> users to work with them even when they are not connected to the network or a
>> server is unavailable. The next time the user connects to the network or the
>> server is available, their offline files on your computer will automatically
>> sync to the network files on the server.
>>
>> I have it set up to keep a local copy of a mapped network drive that holds my
>> files (Cygwin $HOME). As I understand it (eg. explained in
>> https://docs.microsoft.com/en-us/windows-server/storage/folder-redirection/folder-redirection-rup-overview),
>> when the system goes offline, Windows uses the "Folder Redirection" feature to
>> redirect access to the client-side cache, C:\Windows\CSC.
>>
>> I guess Cygwin can choke on this redirected path.
>>> It would also help if you could capture the assertion failure in a debugger.  Do
>>> you know how to use gdb?  If so, I would suggest attaching gdb to bash before
>>> hibernating, and putting a breakpoint at symlink_info::check.  Assuming that gdb
>>> is still usable after you resume from hibernation, we ought to be able to find
>>> the cause of the assertion failure.
>> I will try this, but it will be tricky, because I don't get the assertion every
>> time I go offline / hibernate. I'll see if I can work out how to provoke the bug
>> reliably. I don't remember the situation from every time it's happened, but I
>> think perhaps it can happen if there is a bash window open at the time. bash
>> still works, but it can't run anything else, nor can I start any new processes.
>> If so, your test might be possible, but might not see the symptom, since the
>> problem seems to be in processes started by bash. But I'll try.
> Hi Tim,
>
> I don't know if you noticed the thread starting here:
>
>     https://cygwin.com/ml/cygwin/2019-12/msg00016.html
>
> The problem reported there has been fixed, and I hope that the fix also works
> for your problem.  You can test it by installing the latest snapshot from
> https://cygwin.com/snapshots/.

Hi Ken,

Many thanks for the interesting and encouraging pointer. That does look 
similar to my issue, though I think the other issue was (originally at 
least) something to do with inaccessible mounts, rather than cached mounts.

I have tested the new snapshot and don't see any problems so far. 
However I have been having trouble reproducing my original issue, 
especially since I recreated my offline-files synchronisation 
partnership, so I can't tell for sure whether the update fixes my 
particular problem, or it just went away of its own accord. I'll keep 
exercising it and let you know if I see any more the assertion crash.

Thanks,
Tim.

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple