Re: kern/39777: NFS client triggers kernel panics

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

The following reply was made to PR kern/39777; it has been noted by GNATS.

From: Matthias Scheler <tron%zhadum.org.uk@localhost>
To: netbsd-bugs%NetBSD.org@localhost
Cc: gnats-bugs%NetBSD.org@localhost
Subject: Re: kern/39777: NFS client triggers kernel panics
Date: Fri, 31 Oct 2008 18:30:12 +0000

 I've looked at the faulting bit of code:
 
 db{0}> examine/i netbsd:_bus_dmamap_load_mbuf,10
 netbsd:_bus_dmamap_load_mbuf:   pushq   %rbp
 netbsd:_bus_dmamap_load_mbuf+0x1:       movq    %rsp,%rbp
 netbsd:_bus_dmamap_load_mbuf+0x4:       pushq   %r15
 netbsd:_bus_dmamap_load_mbuf+0x6:       pushq   %r14
 netbsd:_bus_dmamap_load_mbuf+0x8:       pushq   %r13
 netbsd:_bus_dmamap_load_mbuf+0xa:       pushq   %r12
 netbsd:_bus_dmamap_load_mbuf+0xc:       movq    %rsi,%r12
 netbsd:_bus_dmamap_load_mbuf+0xf:       pushq   %rbx
 netbsd:_bus_dmamap_load_mbuf+0x10:      subq    $0x58,%rsp
 netbsd:_bus_dmamap_load_mbuf+0x14:      movq    %rdi,0xffffffffffffffb0(%rbp)
 netbsd:_bus_dmamap_load_mbuf+0x18:      movq    %rdx,0xffffffffffffffa8(%rbp)
 netbsd:_bus_dmamap_load_mbuf+0x1c:      movl    %ecx,0xffffffffffffffa4(%rbp)
 netbsd:_bus_dmamap_load_mbuf+0x1f:      movq    0x30(%rsi),%rax
 netbsd:_bus_dmamap_load_mbuf+0x23:      movq    %rax,0xffffffffffffffb8(%rbp)
 netbsd:_bus_dmamap_load_mbuf+0x27:      movq    $0,0x40(%rsi)
 netbsd:_bus_dmamap_load_mbuf+0x2f:      movl    $0,0x48(%rsi)
 
 The kernel crashes at netbsd:_bus_dmamap_load_mbuf+0x14 which tries
 to access the stack space it previously created.
 
 This looks like a stack overflow to me.
 
        Kind regards
 
 -- 
 Matthias Scheler                                  http://zhadum.org.uk/