Re: rpc.lockd(8) seg faults on 5.2-RELEASE

From: Don Lewis <truckman_at_FreeBSD.org>
Date: Wed, 4 Feb 2004 12:41:11 -0800 (PST)
On  4 Feb, Frode Nordahl wrote:
> 
> On Feb 3, 2004, at 12:06, Don Lewis wrote:
>>
>> Probably not a NULL pointer because &ifl->filehandle will be the same
>> value as (char *)ifl+offsetof(struct file_lock, filehandle), and
>> LIST_FOREACH() will bail out when ifl is NULL.  It would be interesting
>> to walk the lock list starting at nfslocklist_head and following the
>> nfslocklist links so see if any of the link values look bogus.
> 
> hum, on my last core dump, nfslocklist_head->lh_first->le_next and 
> le_prev are uninitialized pointers.
> 
> Other dumps have other results though, I'll look more into it tonight.
> 
> (using malloc.conf -> J)
> 
> (gdb) print *nfslocklist_head->lh_first
> $3 = {nfslocklist = {le_next = 0xd0d0d0d0, le_prev = 0xd0d0d0d0},
>    filehandle = {fh_fsid = {val = {-791621424, -791621424}}, fh_fid = {
>        fid_len = 53456, fid_reserved = 53456,
>        fid_data = '?' <repeats 16 times>}}, addr = 0xd0d0d0d0, client = {
>      exclusive = -791621424, svid = 3503345872, oh = {n_len = 3503345872,
>        n_bytes = 0xd0d0d0d0 <Address 0xd0d0d0d0 out of bounds>},
>      l_offset = 15046755950319947984, l_len = 15046755950319947984},
>    client_cookie = {n_len = 3503345872,
>      n_bytes = 0xd0d0d0d0 <Address 0xd0d0d0d0 out of bounds>},
>    client_name = '?' <repeats 1024 times>, nsm_status = -791621424,
>    status = -791621424, flags = -791621424, blocking = -791621424,
>    locker = -791621424, fd = -791621424}

Since allocate_file_lock() bzero's the entire file_lock structure,
including le_next and le_prev, and since the everything in this
structure appears to be initialized to 0xd0d0d0d0, it looks like
nfslocklist is pointing to something on the free list.  Probably
something is calling deallocate_file_lock() without first removing the
lock from the list.
Received on Wed Feb 04 2004 - 11:41:32 UTC

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