On Thu, Jul 04, 2013 at 07:27:00AM +0200, Andre Albsmeier wrote: > On Thu, 04-Jul-2013 at 07:24:40 +0200, Konstantin Belousov wrote: > > On Thu, Jul 04, 2013 at 07:14:09AM +0200, Andre Albsmeier wrote: > > > On Mon, 17-Jun-2013 at 21:30:31 +0200, John Baldwin wrote: > > > > On Sunday, June 16, 2013 2:39:42 am Andre Albsmeier wrote: > > > > > On Fri, 31-May-2013 at 16:51:03 +0200, John Baldwin wrote: > > > > > > On Friday, May 31, 2013 8:26:11 am Andre Albsmeier wrote: > > > > > > > Each day at 5:15 we are generating snapshots on various machines. > > > > > > > This used to work perfectly under 7-STABLE for years but since > > > > > > > we started to use 9.1-STABLE the machine reboots in about 10% > > > > > > > of all cases. > > > > > > > > > > > > > > After rebooting we find a new snapshot file which is a bit > > > > > > > smaller than the good ones and with different permissions > > > > > > > It does not succeed a fsck. In this example it is the one > > > > > > > whose name is beginning with s3: > > > > > > > > > > > > > > -r--r----- 1 root operator snapshot 72802894528 29 May 05:15 > > > > > > > s2-2013.05.28-03.15.04 > > > > > > > -r-------- 1 root operator snapshot 72802893824 29 May 05:15 > > > > > > > s3-2013.05.29-03.15.03 > > > > > > > -r--r----- 1 root operator snapshot 72802894528 28 May 14:22 > > > > > > > s4-2013.05.23-06.38.44 > > > > > > > -r--r----- 1 root operator snapshot 72802894528 28 May 14:22 > > > > > > > s5-2013.05.24-03.15.03 > > > > > > > -r--r----- 1 root operator snapshot 72802894528 28 May 14:22 > > > > > > > s6-2013.05.25-03.15.03 > > > > > > > > > > > > > > After enabling DIAGNOSTIC, WITNESS and INVARIANTS in the kernel > > > > > > > I see the following LORs (mksnap_ffs starts exactly at 5:15): > > > > > > > > > > > > > > May 29 05:15:00 <kern.crit> palveli kernel: lock order reversal: > > > > > > > May 29 05:15:00 <kern.crit> palveli kernel: 1st 0xc2371da8 ufs > > > > > > > (ufs) @ /src/src-9/sys/kern/vfs_mount.c:1240 > > > > > > > May 29 05:15:00 <kern.crit> palveli kernel: 2nd 0xc2371ec4 devfs > > > > > > > (devfs) @ /src/src-9/sys/ufs/ffs/ffs_vfsops.c:1414 > > > > > > > May 29 05:15:04 <kern.crit> palveli kernel: lock order reversal: > > > > > > > May 29 05:15:04 <kern.crit> palveli kernel: 1st 0xc228471c snaplk > > > > > > > (snaplk) @ /src/src-9/sys/ufs/ufs/ufs_vnops.c:976 > > > > > > > May 29 05:15:04 <kern.crit> palveli kernel: 2nd 0xc22f25e4 ufs > > > > > > > (ufs) @ /src/src-9/sys/ufs/ffs/ffs_snapshot.c:1626 > > > > > > > > > > > > > > Unfortunatley no corefiles are being generated ;-(. > > > > > > > > > > > > > > I have checked and even rebuilt the (UFS1) fs in question > > > > > > > from scratch. I have also seen this happen on an UFS2 on > > > > > > > another machine and on a third one when running "dump -L" > > > > > > > on a root fs. > > > > > > > > > > > > > > Any hints of how to proceed? > > > > > > > > > > > > Would it be possible to setup a serial console that is logged on > > > > > > this machine > > > > > > to see if it is panic'ing but failing to write out a crashdump? > > > > > > > > > > Couldn't attach the serial console yet ;-(. But I had people > > > > > attach a KVMoverIP switch and enabled the various KDB options > > > > > in the kernel. Now we can see a bit more (see below) -- no > > > > > crashdump is being generated though. > > > > > > > > :( Unfortunately these LORs don't really help with discerning the > > > > cause of > > > > the reboot. If you have remote power access (and still wanted to test > > > > this) > > > > one option would be to change KDB to drop into the debugger on a panic. > > > > Then you could connect over the KVM and take images of the original > > > > panic > > > > along with a stack trace. > > > > > > After a few days of no problems, the box decided to crash > > > during mksnap_ffs today ;-(. But now I have a crashdump, > > > see below. Unfortunatley, I cannot upload the dump somewhere > > > but if you ask me check whatever things I'll be happy to help. > > > > > > kgdb /usr/obj/src/src-9/sys/palveli/kernel.debug vmcore.4 > > > GNU gdb 6.1.1 [FreeBSD] > > > Copyright 2004 Free Software Foundation, Inc. > > > GDB is free software, covered by the GNU General Public License, and you > > > are > > > welcome to change it and/or distribute copies of it under certain > > > conditions. > > > Type "show copying" to see the conditions. > > > There is absolutely no warranty for GDB. Type "show warranty" for > > > details. > > > This GDB was configured as "i386-marcel-freebsd"... > > > > > > Unread portion of the kernel message buffer: > > > > > > > > > Fatal trap 12: page fault while in kernel mode > > > fault virtual address = 0xcfb5e000 > > > fault code = supervisor write, page not present > > > instruction pointer = 0x20:0xc07cb2fe > > > stack pointer = 0x28:0xd83545d0 > > > frame pointer = 0x28:0xd835490c > > > code segment = base 0x0, limit 0xfffff, type 0x1b > > > = DPL 0, pres 1, def32 1, gran 1 > > > processor eflags = interrupt enabled, resume, IOPL = 0 > > > current process = 12929 (mksnap_ffs) > > > trap number = 12 > > > panic: page fault > > > KDB: stack backtrace: > > > db_trace_self_wrapper(c08207eb,d835441c,c05fdfc9,c081df13,c08a82e0,...) > > > at db_trace_self_wrapper+0x26/frame 0xd83543ec > > > kdb_backtrace(c081df13,c08a82e0,c0801bfa,d8354428,d8354428,...) at > > > kdb_backtrace+0x29/frame 0xd83543f8 > > > panic(c0801bfa,c0845a01,c2bafae4,1,1,...) at panic+0xc9/frame 0xd835441c > > > trap_fatal(c0ff6000,cfb5e000,2,0,265abf,...) at trap_fatal+0x353/frame > > > 0xd835445c > > > trap_pfault(140da,0,c2baf930,c08b6a40,c282145c,...) at > > > trap_pfault+0x2d7/frame 0xd83544a4 > > > trap(d8354590) at trap+0x41a/frame 0xd8354584 > > > calltrap() at calltrap+0x6/frame 0xd8354584 > > > --- trap 0xc, eip = 0xc07cb2fe, esp = 0xd83545d0, ebp = 0xd835490c --- > > > bcopy(c2b36548,c2f194e0,0,0,0,...) at bcopy+0x1a/frame 0xd835490c > > > ffs_mount(c2b36548,c2db9000,ff,d8354c08,c2b665e4,...) at > > > ffs_mount+0x15ee/frame 0xd8354a3c > > > > From the crash dump in kgdb, do > > list *ffs_mount+0x15ee > > (kgdb) list *ffs_mount+0x15ee > 0xc0748e8e is in ffs_mount (/src/src-9/sys/ufs/ffs/ffs_vfsops.c:483). > 478 > 479 /* > 480 * If this is a snapshot request, take the snapshot. > 481 */ > 482 if (mp->mnt_flag & MNT_SNAPSHOT) > 483 return (ffs_snapshot(mp, fspec)); > 484 } > 485 > 486 /* > 487 * Not an update, or updating the name: look up the name
It is not useful, bcopy does not create a frame, so the real caller
of the failing bcopy gets lost. It could be uncovered with some
stack digging, but I believe it would be easier just fix bcopy.
Please apply this patch and reproduce the panic again, then the kgdb
backtrace should be more useful.
diff --git a/sys/i386/i386/support.s b/sys/i386/i386/support.s
index 967a09e..779fa38 100644
--- a/sys/i386/i386/support.s
+++ b/sys/i386/i386/support.s
@@ -181,11 +181,13 @@ END(bcopyb)
* w...@tools.de (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
*/
ENTRY(bcopy)
+ pushl %ebp
+ movl %esp,%ebp
pushl %esi
pushl %edi
- movl 12(%esp),%esi
- movl 16(%esp),%edi
- movl 20(%esp),%ecx
+ movl 8(%ebp),%esi
+ movl 12(%ebp),%edi
+ movl 16(%ebp),%ecx
movl %edi,%eax
subl %esi,%eax
@@ -196,12 +198,13 @@ ENTRY(bcopy)
cld /* nope, copy forwards */
rep
movsl
- movl 20(%esp),%ecx
+ movl 16(%ebp),%ecx
andl $3,%ecx /* any bytes left? */
rep
movsb
popl %edi
popl %esi
+ popl %ebp
ret
ALIGN_TEXT
@@ -214,7 +217,7 @@ ENTRY(bcopy)
std
rep
movsb
- movl 20(%esp),%ecx /* copy remainder by 32-bit
words */
+ movl 16(%ebp),%ecx /* copy remainder by 32-bit
words */
shrl $2,%ecx
subl $3,%esi
subl $3,%edi
@@ -223,6 +226,7 @@ ENTRY(bcopy)
popl %edi
popl %esi
cld
+ popl %ebp
ret
END(bcopy)
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