releases/2.6.17.11/dm-bug-oops-fix.patch

   1 From stable-bounces@linux.kernel.org Sun Aug 13 23:24:58 2006
   2 Message-Id: <200608140624.k7E6OKjC006995@shell0.pdx.osdl.net>
   3 To: greg@kroah.com
   4 From: akpm@osdl.org
   5 Date: Sun, 13 Aug 2006 23:24:20 -0700
   6 Cc: akpm@osdl.org, torvalds@osdl.org, stable@kernel.org, agk@redhat.com, mirq-linux@rere.qmqm.pl
   7 Subject: dm: BUG/OOPS fix
   8
   9 From: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
  10
  11 Fix BUG I tripped on while testing failover and multipathing.
  12
  13 BUG shows up on error path in multipath_ctr() when parse_priority_group()
  14 fails after returning at least once without error.  The fix is to
  15 initialize m->ti early - just after alloc()ing it.
  16
  17 BUG: unable to handle kernel NULL pointer dereference at virtual address 00000000
  18  printing eip:
  19 c027c3d2
  20 *pde = 00000000
  21 Oops: 0000 [#3]
  22 Modules linked in: qla2xxx ext3 jbd mbcache sg ide_cd cdrom floppy
  23 CPU:    0
  24 EIP:    0060:[<c027c3d2>]    Not tainted VLI
  25 EFLAGS: 00010202   (2.6.17.3 #1)
  26 EIP is at dm_put_device+0xf/0x3b
  27 eax: 00000001   ebx: ee4fcac0   ecx: 00000000   edx: ee4fcac0
  28 esi: ee4fc4e0   edi: ee4fc4e0   ebp: 00000000   esp: c5db3e78
  29 ds: 007b   es: 007b   ss: 0068
  30 Process multipathd (pid: 15912, threadinfo=c5db2000 task=ef485a90)
  31 Stack: ec4eda40 c02816bd ee4fc4c0 00000000 f7e89498 f883e0bc c02816f6 f7e89480
  32        f7e8948c c0281801 ffffffea f7e89480 f883e080 c0281ffe 00000001 00000000
  33        00000004 dfe9cab8 f7a693c0 f883e080 f883e0c0 ca4b99c0 c027c6ee 01400000
  34 Call Trace:
  35  <c02816bd> free_pgpaths+0x31/0x45  <c02816f6> free_priority_group+0x25/0x2e
  36  <c0281801> free_multipath+0x35/0x67  <c0281ffe> multipath_ctr+0x123/0x12d
  37  <c027c6ee> dm_table_add_target+0x11e/0x18b  <c027e5b4> populate_table+0x8a/0xaf
  38  <c027e62b> table_load+0x52/0xf9  <c027ec23> ctl_ioctl+0xca/0xfc
  39  <c027e5d9> table_load+0x0/0xf9  <c0152146> do_ioctl+0x3e/0x43
  40  <c0152360> vfs_ioctl+0x16c/0x178  <c01523b4> sys_ioctl+0x48/0x60
  41  <c01029b3> syscall_call+0x7/0xb
  42 Code: 97 f0 00 00 00 89 c1 83 c9 01 80 e2 01 0f 44 c1 88 43 14 8b 04 24 59 5b 5e 5f 5d c3 53 89 c1 89 d3 ff 4a 08 0f 94 c0 84 c0 74 2a <8b> 01 8b 10 89 d8 e8 f6 fb ff ff 8b 03 8b 53 04 89 50 04 89 02
  43 EIP: [<c027c3d2>] dm_put_device+0xf/0x3b SS:ESP 0068:c5db3e78
  44
  45 Signed-off-by: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
  46 Acked-by: Alasdair G Kergon <agk@redhat.com>
  47 Signed-off-by: Andrew Morton <akpm@osdl.org>
  48 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  49
  50 ---
  51  drivers/md/dm-mpath.c |    3 ++-
  52  1 file changed, 2 insertions(+), 1 deletion(-)
  53
  54 --- linux-2.6.17.9.orig/drivers/md/dm-mpath.c
  55 +++ linux-2.6.17.9/drivers/md/dm-mpath.c
  56 @@ -711,6 +711,8 @@ static int multipath_ctr(struct dm_targe
  57                 return -EINVAL;
  58         }
  59
  60 +       m->ti = ti;
  61 +
  62         r = parse_features(&as, m, ti);
  63         if (r)
  64                 goto bad;
  65 @@ -752,7 +754,6 @@ static int multipath_ctr(struct dm_targe
  66         }
  67
  68         ti->private = m;
  69 -       m->ti = ti;
  70
  71         return 0;
  72