Re: kern/46221: Kernel panic in NFS server code

[Matthias Scheler <tron%zhadum.org.uk@localhost>]

The following reply was made to PR kern/46221; it has been noted by GNATS.

From: Matthias Scheler <tron%zhadum.org.uk@localhost>
To: NetBSD GNATS <gnats-bugs%NetBSD.org@localhost>
Cc: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
Subject: Re: kern/46221: Kernel panic in NFS server code
Date: Tue, 20 Mar 2012 23:40:32 +0000

 On Sun, Mar 18, 2012 at 10:35:02PM +0000, Matthias Scheler wrote:
 > The following reply was made to PR kern/46221; it has been noted by GNATS.
 > 
 > From: Matthias Scheler <tron%zhadum.org.uk@localhost>
 > To: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
 > Cc: NetBSD GNATS <gnats-bugs%NetBSD.org@localhost>
 > Subject: Re: kern/46221: Kernel panic in NFS server code
 > Date: Sun, 18 Mar 2012 22:32:25 +0000
 > 
 >  On Sun, Mar 18, 2012 at 07:16:28PM +0100, Manuel Bouyer wrote:
 >  > (gdb) l *(ffs_fhtovp+0x55)
 >  > 0xffffffff801af684 is in ffs_fhtovp 
 > (/usr/src/sys/ufs/ffs/ffs_vfsops.c:1907).
 >  > 1902    /usr/src/sys/ufs/ffs/ffs_vfsops.c: No such file or directory.
 >  >         in /usr/src/sys/ufs/ffs/ffs_vfsops.c
 >  > 
 >  > But this is at the very end of ffs_fhtovp(). I don't know if ddb is 
 > somewhat
 >  > confused when computing the stack trace, or something else.
 >  > 
 >  > (gdb) x/i ffs_fhtovp+0x55
 >  >    0xffffffff801af684 <ffs_fhtovp+85>:  leaveq 
 >  > (gdb) disas ffs_fhtovp
 >  > [...]
 >  >    0xffffffff801af67f <+80>:    callq  0xffffffff8042b0f3 <ufs_fhtovp>
 >  >    0xffffffff801af684 <+85>:    leaveq 
 >  >    0xffffffff801af685 <+86>:    retq   
 >  > 
 >  > Either ddb skipped the call to ufs_fhtovp (and so the place where it
 >  > crashed in ufs_fhtovp) or the stack is corrupted.
 >  > The exact trap message from ddb and the register dump would be usefull.
 >  
 >  I'll try to get that the next time.
 
 I got a new back-trace ...
 
 b{1}> bt
 ufs_fhtovp() at netbsd:ufs_fhtovp+0x2e
 ffs_fhtovp() at netbsd:ffs_fhtovp+0x55
 VFS_FHTOVP() at netbsd:VFS_FHTOVP+0x1c
 dofhopen() at netbsd:dofhopen+0xda
 syscall() at netbsd:syscall+0xc4
 
 ... and a register dump:
 
 db{1}> sh registers
 ds          9a90
 es          7480
 fs          9a30
 gs          a000
 rdi         fffffe81c281bac0
 rsi         0
 rbp         fffffe810eda9a80
 rbx         fffffe810eda9a90
 rdx         0
 rcx         7
 rax         0
 r8          fffffe810e9b3000
 r9          0
 r10         1
 r11         0
 r12         fffffe810eda9bc0
 r13         3
 r14         1c
 r15         7f7ff7b4f3c0
 rip         ffffffff8042b121    ufs_fhtovp+0x2e
 cs          8
 rflags      10246
 rsp         fffffe810eda9a60
 ss          10
 netbsd:ufs_fhtovp+0x2e: cmpw    $0,c8(%rdx)
 
 I didn't know how to get the panic message.
 
        Kind regards
 
 -- 
 Matthias Scheler                                  http://zhadum.org.uk/