Re: port-xen/53074: Daily 8.99.12 DOMU panic

[Brad Spencer <brad%anduin.eldar.org@localhost>]

The following reply was made to PR port-xen/53074; it has been noted by GNATS.

From: Brad Spencer <brad%anduin.eldar.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: port-xen-maintainer%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
        netbsd-bugs%netbsd.org@localhost
Subject: Re: port-xen/53074: Daily 8.99.12 DOMU panic
Date: Mon, 05 Mar 2018 21:30:03 -0500

 coypu%sdf.org@localhost writes:
 
 >  You can parse the backtrace like so (normally, it would report the
 >  functions, but that is a bug).
 >  
 >  gdb /my-netbsd-kernel
 >  info symbol 0xffffffff804f74b8
 >  
 >  and so on.
 
 I have compiled a new kernel with debugging symbols which may prove more
 helpful.  But in the meantime, using the original kernel I get the
 following:
 
 ?() at ffffffff804f74b8
 ?() at ffffffff80600b95
 ?() at ffffffff802139eb
 ?() at ffffffff8022eb90
 ?() at ffffffff80212a48
 ?() at ffffffff80203119
 ?() at ffffffff804cd598
 ?() at ffffffff804b2ae6
 ?() at ffffffff8020f1a6
 
 (gdb) info symbol 0xffffffff804f74b8
 vpanic + 320 in section .text
 (gdb) info symbol 0xffffffff80600b95
 No symbol matches 0xffffffff80600b95.
 (gdb) info symbol 0xffffffff802139eb
 xengnt_free_entry + 155 in section .text
 (gdb) info symbol 0xffffffff8022eb90
 xbd_handler + 223 in section .text
 (gdb) info symbol 0xffffffff80212a48
 xen_intr_biglock_wrapper + 29 in section .text
 (gdb) info symbol 0xffffffff80203119
 Xresume_xenev6 + 73 in section .text
 (gdb) info symbol 0xffffffff804cd598
 softint_overlay + 1278 in section .text
 (gdb) info symbol 0xffffffff804b2ae6
 lwp_userret + 521 in section .text
 (gdb) info symbol 0xffffffff8020f1a6
 syscall + 406 in section .text
 
 
 >  To check the value of entry, I suspect this will do:
 >  
 >  Index: xengnt.c
 >  ===================================================================
 >  RCS file: /cvsroot/src/sys/arch/xen/xen/xengnt.c,v
 >  retrieving revision 1.25
 >  diff -u -r1.25 xengnt.c
 >  --- xengnt.c	24 Oct 2012 13:07:46 -0000	1.25
 >  +++ xengnt.c	6 Mar 2018 01:47:55 -0000
 >  @@ -261,7 +261,8 @@
 >   xengnt_free_entry(grant_ref_t entry)
 >   {
 >   	mutex_enter(&grant_lock);
 >  -	KASSERT(entry > NR_RESERVED_ENTRIES);
 >  +	KASSERTMSG(entry > NR_RESERVED_ENTRIES,
 >  +	    "entry > NR_RESERVED_ENTRIES and entry is %d", entry);
 >   	KASSERT(gnt_entries[last_gnt_entry] == XENGNT_NO_ENTRY);
 >   	KASSERT(last_gnt_entry >= 0);
 >   	KASSERT(last_gnt_entry <= gnt_max_grant_frames * NR_GRANT_ENTRIES_PER_PAGE);
 >  
 >  
 >  Write the above to a file, and use patch -p0 < /path/to/patch-file
 >  and rebuild a new kernel:
 >  cd src; ./build.sh -U -u -m amd64 -O ~/xen tools kernel=XEN3_DOMU
 >  
 
 I can apply a patch in a day or so and recompile.  If the panic happens
 on schedule it should occur late afternoon tomorrow.
 
 
 
 
 
 -- 
 Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS
 http://anduin.eldar.org  - & -  http://anduin.ipv6.eldar.org [IPv6 only]