Man Linux: Main Page and Category List


       !!!NOTICE!!!   !!!NOTICE!!!   !!!NOTICE!!!   !!!NOTICE!!!   !!!NOTICE!!!!
       !                                                                       !
       ! Revision 1.29 represents the end of life for lslk.  I don’t have time !
       ! to support it.  Please don’t report bugs to me.  I will politely      !
       ! decline to work on them.                                              !
       !                                                                       !
       ! Vic Abell <>, July 11, 2001                             !
       !                                                                       !
       !!!NOTICE!!!   !!!NOTICE!!!   !!!NOTICE!!!   !!!NOTICE!!!   !!!NOTICE!!!!


       lslk - list local locks


       lslk [ -abhnOvw ] [ -i i ] [ -k k ] [ -p p ] [ -S [t] ] [ paths ]


       Lslk  revision  1.29  lists  information about locks held on files with
       local inodes on systems running the following UNIX dialects:

            AIX 3.2.5, 4.1.4, 4.2[.1], and AIX 4.3[.[12]]
            DEC OSF/1, Digital UNIX, and Tru64 UNIX [2345].[01] and 3.2
            SCO OpenDesktop or OpenServer 3.0 and 5.0.[0245]
            Sequent PTX 2.1.9, 4.2.1, 4.3, and 4.4
            Solaris 2.[345], 2.5.1, 2.6, 7, and 8 (excluding Veritas
               VxFS local files)
            SunOS 4.1.3

       The lock may belong to a process on the local system or to a process on
       an  NFS  client  system  to  which  the  local system is an NFS server.
       Notes: Linux and PTX 2.1.9 lslk don’t  report  on  locks  held  by  NFS
       clients;  Solaris  lslk  won’t  report locks held on local Veritas VxFS


       In the absence of any options, lslk lists all locks associated with the
       local files of the system.

       When  selection  options  are  specified,  the  listing of all locks is
       disabled, and the selection options  are  ORed  together.   Only  locks
       meeting any selection criterion are listed.

       When  the -a option is specified, the listing of all locks is disabled,
       and the selection options are ANDed together.  Only locks that meet all
       selection criteria are listed.

       -a       This  option  causes  list  selection  options to be ANDed, as
                described above.

       -b       This option causes lslk to avoid kernel functions  that  might
                block - lstat(2), readlink(2), and stat(2).

                See  the  BLOCKS  AND  TIMEOUTS  and  AVOIDING  KERNEL  BLOCKS
                sections for information on using this option.

       -i i     This option selects the listing of locks whose owning  process
                is on the Internet host whose name or network address is i.

                Multiple addresses may be declared with multiple -i i options.

       -k k     This option specifies k as an alternate to the default  kernel
                name  list  file path.  The default kernel name list file path
                is listed in the -h help output.

                It may be necessary to specify an alternate kernel  name  list
                path when the file at the default path isn’t the booted kernel
                -- e.g., the default is /vmunix, but the booted kernel file is

                Unless lslk accesses the correct kernel name list file, it may
                derive incorrect  addresses  for  symbols  in  kernel  memory,
                causing it to fail.

       -n       This  option  inhibits the conversion of network host names to
                network addresses and the conversion of network  addresses  to
                network host names.

                This  option  may  be  useful  when  the  host name to address
                translation service (e.g., the Domain Name Server) is slow  or

                If  you  use  this  option  on  hosts  whose kernel lock table
                contains only host names - e.g., SCO or Solaris - or  you  use
                this  option  and  also  select  the  listing  of  locks by an
                Internet network address with the -i i option, lslk  will  not
                be  able  to  locate  any  locks  with  the  specified network
                address, nor will it be able to report  network  addresses  in
                its  output.   The -n option inhibits the necessary conversion
                of kernel lock table host names to network addresses.

       -O       This option directs lslk to bypass the  strategy  it  uses  to
                avoid  being  blocked  by some kernel operations - i.e., doing
                them in forked child processes.  See the BLOCKS  AND  TIMEOUTS
                and  AVOIDING  KERNEL  BLOCKS sections for more information on
                kernel operations that may block lslk.

       -p p     This option selects the listing of locks whose owning  process
                IDentification  (PID) numbers are in the comma-separated list,

       -S [t]   This option specifies an optional time-out seconds  value  for
                kernel  functions  - lstat(2), readlink(2), and stat(2) - that
                might otherwise deadlock.  The  minimum  for  t  is  two;  the
                default,  fifteen;  when no value is specified, the default is

                See the BLOCKS AND TIMEOUTS section for more information.

       -v       When this option is specified, lslk lists version  information
                - i.e., where, when and how it was constructed.

       -w       This option suppresses non-fatal warning messages.

       paths    This option specifies a list of file path names for which lslk
                is to list lock information.


       Lslk lists the information for each lock on  a  separate  line  in  the
       following columns.  (The columns are dynamically sized.)

       SRC     indicates the source of the process holding the lock.

               If  the  source  is  a  local  process,  its  command  name  is
               displayed, or  ‘‘(unknown)’’  if  the  command  name  can’t  be

               If  the  source  is  a remote process, the host name or network
               number where the remote process executes is displayed.

       PID     is the Process IDentification number of the process holding the

       DEV     is  the  device  (major  and minor numbers) on which the locked
               file resides.

       INUM    is the inode number of the locked file.

       SZ      is the size of the locked file.

       TY      is the lock type:
                         r    read;
                         rw   read and write;
                         w    write;
                         ?    unknown.

       M       is the mandatory state of the lock: 0 if none; 1 if set.   (See

       ST      is the relative byte offset of the lock.

       WH      is the starting offset (‘‘whence’’) of the lock.

       END     is the ending offset of the lock.

       LEN     is the length of the lock.

       NAME    is  the  name of the locked file, if it was specified as a path

               If there is no path argument name, then  the  mount  point  and
               device  paths  of  the  file  system  on  which the locked file
               resides are displayed.


       Lslk can be blocked by some kernel functions that it uses  -  lstat(2),
       readlink(2),  and  stat(2).  These functions are stalled in the kernel,
       for example, when the hosts  where  mounted  NFS  file  systems  reside
       become inaccessible.

       Lslk  attempts  to  break these blocks with timers and child processes,
       but the techniques are not wholly reliable.  When lslk does  manage  to
       break  a  block,  it  will report the break with an error message.  The
       messages may be suppressed with the -w option.

       The default timeout value may be displayed with the -h option,  and  it
       may  be  changed  with  the  -S  [t]  option.  The minimum for t is two
       seconds,  but  you  should  avoid  small  values,  since  slow   system
       responsiveness  can  cause  short  timeouts  to expire unexpectedly and
       perhaps stop lslk before it can produce any output.

       When lslk has to break a block during its access of mounted file system
       information,  it  normally  continues,  although  with less information
       available to display about open files.

       Lslk can also be directed to avoid the protection of timers  and  child
       processes   when  using  the  kernel  functions  that  might  block  by
       specifying the -O option.  While this will allow lslk to start up  with
       less overhead, it exposes lslk completely to the kernel situations that
       might block it.  Use this option cautiously.


       You can use the -b option to tell lslk to avoid using kernel  functions
       that would block.  Some cautions apply.

       First,  using  this  option  usually  requires  that your system supply
       alternate device numbers in place of the device numbers that lslk would
       normally  obtain  with  the lstat(2) and stat(2) kernel functions.  See
       the ALTERNATE DEVICE NUMBERS section for more information on  alternate
       device numbers.

       Second,  you  can’t  specify the names of files you want lslk to locate
       locks for unless they’re file system names.  This is because lslk needs
       to  know the device and inode numbers of files listed with names in the
       lslk options, and the -b option  prevents  lslk  from  obtaining  them.
       Moreover,  since lslk only has device numbers for the file systems that
       have alternates, its ability to locate locks on  file  systems  depends
       completely  on  the availability and accuracy of the alternates.  If no
       alternates are available, or if they’re incorrect, lslk won’t  be  able
       to locate locks on the named file systems.

       Third,  if  the names of your file system directories that lslk obtains
       from your system’s mount table are symbolic links, lslk won’t  be  able
       to  resolve  the  links.   This is because the -b option causes lslk to
       avoid the kernel readlink(2)  function  it  uses  to  resolve  symbolic

       Finally, using the -b option causes lslk to issue warning messages when
       it needs to use the kernel functions that the -b option directs  it  to
       avoid.   You  can  suppress these messages by specifying the -w option,
       but if you do, you won’t see the alternate device numbers  reported  in
       the warning messages.


       On  some  dialects, when lslk has to break a block because it can’t get
       information about a mounted file system via the  lstat(2)  and  stat(2)
       kernel  functions,  or  because  you  specified the -b option, lslk can
       obtain some of the  information  it  needs  -  the  device  number  and
       possibly the file system type - from the system mount table.  When that
       is possible, lslk will report the device number it obtained.  (You  can
       suppress the report by specifying the -w option.)

       You  can  assist  this process if your mount table is supported with an
       /etc/mtab or /etc/mnttab file that contains an options field by  adding
       a  ‘‘dev=xxxx’’  field  for  mount points that do not have one in their
       options strings.

       The ‘‘xxxx’’ portion of the field is the hexadecimal value of the  file
       system’s device number.  (Consult the st_dev field of the output of the
       lstat(2) and stat(2) functions for the appropriate values for your file
       systems.)   Here’s  an example from a Solaris 2.5 /etc/mnttab for a UFS
       file system:

            ... ufs suid,rw,dev=80001f ...

       Some dialects that do not use an ASCII /etc/mtab  or  /etc/mnttab  file
       for  the  mount table may still provide an alternative device number in
       their internal mount tables.  This includes  AIX,  DEC  OSF/1,  Digital
       UNIX,  and Tru64 UNIX.  Lslk knows how to obtain the alternative device
       number for these dialects and uses it when its attempt to  lstat(2)  or
       stat(2) the file system is blocked.

       If  you’re  not sure your dialect supplies alternate device numbers for
       file systems from its mount table, use this lslk incantation to see  if
       it reports any alternate device numbers:

              lslk -b

       Look  for  standard  error  file warning messages that begin ‘‘assuming
       "dev=xxxx" from ...’’.


       Errors are identified with messages on the standard error file.

       Lslk returns a one (1) if an error was detected or if it couldn’t  list
       lock information for all the names that were specified.


       To list all locks, use:


       To list locks from the host ‘‘klaatu’’ in the local domain, use:

              lslk -i klaatu

       To    list    locks    from    the   hosts   and, use:

              lslk -i -i

       To list locks held by processes 1234 and 56789, use:

              lslk -p 1234,56789

       To list all locks held by process 1234 on host klaatu, use:

              lslk -p 1234 -a -i klaatu


       Lslk must have permission to access the system  memory  files  -  e.g.,
       /dev/kmem and /dev/mem.  Permission to do that is granted when the lslk
       process is run from a root shell, or when its ‘‘setgid’’ group  matches
       the group (e.g., ‘‘sys’’) that can read the system memory files.


       Perhaps  it  should  be  possible to specify the host on which a search
       target PID is located.

       DEC OSF/1, Digital UNIX, and Tru64 UNIX lslk won’t find  locks  applied
       with  the  flock(2)  function.   It  will  find  locks applied with the
       fcntl(2) and lockf(3) functions.

       Linux lslk will not report locks held by  NFS  clients.   It  may  have
       difficulty reporting locks held on dynamic inodes (e.g., for the Win-95
       file system type, smbfs).

              Solaris lslk won’t find locks held on local Veritas  VxFS  files
              by local or remote processes.


       /dev/kmem    kernel virtual memory device

       /dev/mem     physical memory device


       Lslk  was  written  by  Victor  A. Abell <> of the Purdue
       University Computing Center (PUCC).

       Chris Eleveld <> did  the  DEC  OSF/1,  Digital  UNIX,
       Linux, and Tru64 UNIX ports.


       chmod(1),   fcntl(2),   fcntl(5),   flock(3B),   lockd(1M),   lstat(2),
       lockf(3C), readlink(2), stat(2).