36823 - DNS disappears after browser crash

Status: VERIFIED INVALID

(SeaMonkey :: General, defect, P3)

Description

[shai]

When working with M15 (and PR1) on rare occasions when the browser crashes
I can no longer see the DNS server (cannot ping the DNS IP). Rebooting
the machine doesn't help... Only waiting atleast 15 minutes seems to restore
the DNS.
Other machines can see the DNS, and from the problem machine I can see my
router but not the DNS.

I belive this bug is related to:
http://bugzilla.mozilla.org/show_bug.cgi?id=26506 but I am not sure (that is why
I filed a separte bug). I can give an engineer access to my machine but
recreating the bug is very hard.

Comment 1

[Wan-Teh Chang]

This bug is not related to bug #26506.  The "DNS lock" in
bug #26506 is a lock (implemented with a pthread mutex on
Linux) used internally by NSPR to serialize all the
gethostbyname() calls made by a process using NSPR.
It only affects the threads within the same process, and
it is gone when a process exits.

I don't see anything in the description of this bug that
shows this is an NSPR bug.  Moreover, it is strange that
the crash of a process (in this case the browser) can
prevent your machine from seeing the DNS server's
*IP address* (which means DNS lookup is not involved),
even after a reboot.  The fact that the problem was not
fixed by rebooting and that the problem disappeared
after waiting >= 15 minutes seem to indicate that this
could have been a transient network problem.

Could you provide some more information to show that
this could have been caused by NSPR or the browser?
Otherwise, I'm afraid that I'll have to resolve this
bug as INVALID.

Comment 2

[shai]

I have no proof that the bug is within mozilla (in fact I belive this is a bug
in Linux caused by Mozilla). I checked the hardware reformatted the HD changed
my passwords & network cabels etc...
I stil don't belive it is a bug in Mozilla but rather a bug in Linux that is
triggered upon Mozilla crashing in a specific context. I know this is highly
unlikely, I myself didn't belive it until it reocurred consistently with Mozilla
running. I could ping the router so it was not a simple network problem, other
machines (on the same hub) could ping the DNS while I could not.

Comment 3

[Wan-Teh Chang]

It would be useful if you could get the core dump or
the stack trace at the crash.  Then at least we'll have
some idea of the context in which Mozilla crashed.
However, this may be very hard to do because the pthread
library on Linux does not generate a usable core file.
The only way I know of to get a correct stack trace is
to make the program crash inside a debugger.

Can you reproduce this problem on other machines or just
your machine?

Could you ping other hosts (in addition to the router)
when the problem occurred?  Was the DNS server the only
host that didn't respond to your pinging?

Again, there is not enough information that I can
work with to help you.  I'm planning to do one of the
following with this bug:
1. Change the product to "Browser".  (Note that NSPR
   is a stand-alone library that the browser uses.)
   I'm afraid that the browser people won't be able to
   help either though.
2. Resolve the bug as INVALID or WONTFIX.  Your bug
   report will stay in the database, which other people
   can search in case they run into the same problem.

Comment 4

[leger]

Adding crash keyword.

Comment 5

[Wan-Teh Chang]

Changed Product to Browser, Component to Browser-General.

I recommend resolving this bug as INVALID or WONTFIX
because this is not a bug in Mozilla.

Comment 6

[Asa Dotzler [:asa]]

marking this invalid.  if this is found to be a bug in mozilla, please reopen.

Comment 7

[Asa Dotzler [:asa]]

Sorry for the spam.  New QA Contact for Browser General.  Thanks for your help
Joseph (good luck with the new job) and welcome aboard Doron Rosenberg

Comment 8

[Doron Rosenberg (IBM)]

verified