notmuch segfault

notmuch segfault

[Sebastian Spaeth]

Sorry, I won't be able to offer much debug info, but the current stock
cworth/master segfaulted for me with only the "tag:inbox" search.

Output:
/home/spaetz/mail/INBOX/new/...2c57e:2,: No such file or directory
Segmentation fault (core dumped)

A "notmuch new" fixed the segfault, something is not as robust as it
should be (or used to be), it seems. I'll dig deeper if it occurs again.

Sebastian

Re: notmuch segfault

[Sebastian Spaeth]

It happened again. Both times I had pressed "G" which calls offlineimap
and which removed messages that the notmuch database still thought are there.

----------------------------------------------------------------
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff602bb14 in strncasecmp () from /lib/libc.so.6
(gdb) bt
#0  0x00007ffff602bb14 in strncasecmp () from /lib/libc.so.6
#1  0x0000000000418521 in _thread_add_matched_message(_notmuch_thread*, _notmuch_message*, notmuch_sort_t) ()
#2  0x0000000000418b17 in _notmuch_thread_create ()
#3  0x000000000040e33c in notmuch_show_command ()
#4  0x0000000000408436 in main ()

-------------------------------------------------------------
spaetz@spaetz-macbook:~/src/notmuch$ notmuch show tag:inbox
Error opening /home/spaetz/mail/INBOX.Junk/new/1272025029_0.17175.spaetz-macbook,U=3608,FMD5=22888fa7f8daa670f25d806e9b4ae4df:2,: No such file or directory
Error opening /home/spaetz/mail/INBOX.Junk/new/1272025029_0.17175.spaetz-macbook,U=3608,FMD5=22888fa7f8daa670f25d806e9b4ae4df:2,: No such file or directory
Error opening /home/spaetz/mail/INBOX.Junk/new/1272025029_0.17175.spaetz-macbook,U=3608,FMD5=22888fa7f8daa670f25d806e9b4ae4df:2,: No such file or directory
Segmentation fault (core dumped)

----------------------------------------------------------
Coredump is here:
http://sspaeth.de/uploads/tmp/core.bin
-------------------------------------------------------------


Can it be that in thread.cc in _thread_add_matched_message ()
...
    subject = notmuch_message_get_header (message, "subject");

    if ((strncasecmp (subject, "Re: ", 4) == 0) ||
...

If the underlying message disappeared, get_header will return NULL and
we pass strncasecmp NULL as first parameter. Could that be?

Re: notmuch segfault

[Michal Sojka]

On Fri, 23 Apr 2010, Sebastian Spaeth wrote:
> Can it be that in thread.cc in _thread_add_matched_message ()
> ...
>     subject = notmuch_message_get_header (message, "subject");
> 
>     if ((strncasecmp (subject, "Re: ", 4) == 0) ||
> ...
> 
> If the underlying message disappeared, get_header will return NULL and
> we pass strncasecmp NULL as first parameter. Could that be?

Yes, it is very likely the problem. The fix is obvious (see bellow), but
the question is how will be this "missing message" presented to the user
e.g. in notmuch show. It may be that we will need some other checks to
not break other things.

diff --git a/lib/thread.cc b/lib/thread.cc
index 5bf8354..29b8336 100644
--- a/lib/thread.cc
+++ b/lib/thread.cc
@@ -148,6 +148,9 @@ _thread_add_matched_message (notmuch_thread_t *thread,
 
     subject = notmuch_message_get_header (message, "subject");
 
+    if (!subject)
+       return;
+
     if ((strncasecmp (subject, "Re: ", 4) == 0) ||
        (strncasecmp (subject, "Aw: ", 4) == 0) ||
        (strncasecmp (subject, "Vs: ", 4) == 0) ||

Re: notmuch segfault

[Carl Worth]

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On Fri, 23 Apr 2010 15:26:51 +0200, "Sebastian Spaeth" <Sebastian@SSpaeth.de> wrote:
> It happened again. Both times I had pressed "G" which calls offlineimap
> and which removed messages that the notmuch database still thought are there.

Thanks for the report, Sebastian.

I've just audited all calls to notmuch_message_get_header and tried to
handle NULL in all cases.

Of course, I haven't tested this thoroughly, but we'll hope that things
are better at least.

And perhaps someday someone will hook up some exhaustive
fault-injection-based testing to catch things like this.

-Carl

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