The following reply was made to PR kern/151758; it has been noted by GNATS.

From: John Baldwin <[email protected]>
To: [email protected], [email protected], 
 Konstantin Belousov <[email protected]>
Cc:  
Subject: Re: kern/151758: [panic] tmux kernel panic, with out root privilegies
Date: Thu, 08 Dec 2011 10:24:56 -0500

 The bug is that during unp_gc(), we pass NULL as the thread to closef() 
 (to disable certain locking stuff, and because the thread performing the 
 gc doesn't "own" orphaned file descriptors in a closed UNIX domain 
 socket).  That resulted in the 'td' argument passed to devfs_close_f() 
 being NULL, so td->td_fpop would fault.  The patch I have (untested) is 
 to force devfs_close_f() to always use curthread instead of trusting the 
 td argument it is given.
 
 Index: /home/jhb/work/freebsd/svn/head/sys/fs/devfs/devfs_vnops.c
 ===================================================================
 --- /home/jhb/work/freebsd/svn/head/sys/fs/devfs/devfs_vnops.c (revision 
 228311)
 +++ /home/jhb/work/freebsd/svn/head/sys/fs/devfs/devfs_vnops.c (working 
 copy)
 @@ -602,6 +602,11 @@
        int error;
        struct file *fpop;
 
 +      /*
 +       * NB: td may be NULL if this descriptor is closed due to
 +       * garbage collection from a closed UNIX domain socket.
 +       */
 +      td = curthread;
        fpop = td->td_fpop;
        td->td_fpop = fp;
        error = vnops.fo_close(fp, td);
 
 
 -- 
 John Baldwin
_______________________________________________
[email protected] mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-bugs
To unsubscribe, send any mail to "[email protected]"

Reply via email to