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Namhyung Kim 3b2710824e nbd: limit module parameters to a sane value 
The 'max_part' parameter controls the number of maximum partition
a nbd device can have. However if a user specifies very large
value it would exceed the limitation of device minor number and
can cause a kernel oops (or, at least, produce invalid device
nodes in some cases).

In addition, specifying large 'nbds_max' value causes same
problem for the same reason.

On my desktop, following command results to the kernel bug:

$ sudo modprobe nbd max_part=100000
 kernel BUG at /media/Linux_Data/project/linux/fs/sysfs/group.c:65!
 invalid opcode: 0000 [#1] SMP
 last sysfs file: /sys/devices/virtual/block/nbd4/range
 CPU 1
 Modules linked in: nbd(+) bridge stp llc kvm_intel kvm asus_atk0110 sg sr_mod cdrom

 Pid: 2522, comm: modprobe Tainted: G        W   2.6.39-leonard+ #159 System manufacturer System Product Name/P5G41TD-M PRO
 RIP: 0010:[<ffffffff8115aa08>]  [<ffffffff8115aa08>] internal_create_group+0x2f/0x166
 RSP: 0018:ffff8801009f1de8  EFLAGS: 00010246
 RAX: 00000000ffffffef RBX: ffff880103920478 RCX: 00000000000a7bd3
 RDX: ffffffff81a2dbe0 RSI: 0000000000000000 RDI: ffff880103920478
 RBP: ffff8801009f1e38 R08: ffff880103920468 R09: ffff880103920478
 R10: ffff8801009f1de8 R11: ffff88011eccbb68 R12: ffffffff81a2dbe0
 R13: ffff880103920468 R14: 0000000000000000 R15: ffff880103920400
 FS:  00007f3c49de9700(0000) GS:ffff88011f800000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: 00007f3b7fe7c000 CR3: 00000000cd58d000 CR4: 00000000000406e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
 Process modprobe (pid: 2522, threadinfo ffff8801009f0000, task ffff8801009a93a0)
 Stack:
  ffff8801009f1e58 ffffffff812e8f6e ffff8801009f1e58 ffffffff812e7a80
  ffff880000000010 ffff880103920400 ffff8801002fd0c0 ffff880103920468
  0000000000000011 ffff880103920400 ffff8801009f1e48 ffffffff8115ab6a
 Call Trace:
  [<ffffffff812e8f6e>] ? device_add+0x4f1/0x5e4
  [<ffffffff812e7a80>] ? dev_set_name+0x41/0x43
  [<ffffffff8115ab6a>] sysfs_create_group+0x13/0x15
  [<ffffffff810b857e>] blk_trace_init_sysfs+0x14/0x16
  [<ffffffff811ee58b>] blk_register_queue+0x4c/0xfd
  [<ffffffff811f3bdf>] add_disk+0xe4/0x29c
  [<ffffffffa007e2ab>] nbd_init+0x2ab/0x30d [nbd]
  [<ffffffffa007e000>] ? 0xffffffffa007dfff
  [<ffffffff8100020f>] do_one_initcall+0x7f/0x13e
  [<ffffffff8107ab0a>] sys_init_module+0xa1/0x1e3
  [<ffffffff814f3542>] system_call_fastpath+0x16/0x1b
 Code: 41 57 41 56 41 55 41 54 53 48 83 ec 28 0f 1f 44 00 00 48 89 fb 41 89 f6 49 89 d4 48 85 ff 74 0b 85 f6 75 0b 48 83
  7f 30 00 75 14 <0f> 0b eb fe b9 ea ff ff ff 48 83 7f 30 00 0f 84 09 01 00 00 49
 RIP  [<ffffffff8115aa08>] internal_create_group+0x2f/0x166
  RSP <ffff8801009f1de8>
 ---[ end trace 753285ffbf72c57c ]---

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Laurent Vivier <Laurent.Vivier@bull.net>
Cc: Paul Clements <Paul.Clements@steeleye.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-05-28 14:44:46 +02:00
..
aoe drivers/block/aoe/Makefile: replace the use of <module>-objs with <module>-y 2011-01-19 08:25:02 -07:00
drbd Merge branch 'for-2.6.40/drivers' of git://git.kernel.dk/linux-2.6-block 2011-05-25 09:15:35 -07:00
paride Merge commit 'v2.6.39' into for-2.6.40/core 2011-05-20 20:33:15 +02:00
xen-blkback xen/blkback: don't fail empty barrier requests 2011-05-18 11:28:16 -04:00
amiflop.c block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers 2011-04-21 21:33:05 +02:00
ataflop.c block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers 2011-04-21 21:33:05 +02:00
brd.c brd: export module parameters 2011-05-26 21:06:50 +02:00
cciss_cmd.h cciss: use new doorbell-bit-5 reset method 2011-05-06 08:23:55 -06:00
cciss_scsi.c cciss: add cciss_tape_cmds module paramter 2011-05-06 08:23:59 -06:00
cciss_scsi.h cciss: add cciss_tape_cmds module paramter 2011-05-06 08:23:59 -06:00
cciss.c cciss: fix compile issue 2011-05-06 08:27:00 -06:00
cciss.h cciss: increase timeouts for post-reset no-ops 2011-05-06 08:23:54 -06:00
cpqarray.c block: remove per-queue plugging 2011-03-10 08:52:07 +01:00
cpqarray.h
cryptoloop.c
DAC960.c block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers 2011-04-21 21:33:05 +02:00
DAC960.h
floppy.c block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers 2011-04-21 21:33:05 +02:00
hd.c Fix common misspellings 2011-03-31 11:26:23 -03:00
ida_cmd.h
ida_ioctl.h
Kconfig xen/blkback: Flesh out the description in the Kconfig. 2011-05-12 17:55:40 -04:00
loop.c loop: export module parameters 2011-05-27 07:59:25 +02:00
Makefile xen/blkback: Move it from drivers/xen to drivers/block 2011-04-18 14:30:26 -04:00
mg_disk.c
nbd.c nbd: limit module parameters to a sane value 2011-05-28 14:44:46 +02:00
osdblk.c
pktcdvd.c Merge branch 'for-2.6.39/stack-plug' into for-2.6.39/core 2011-03-10 08:58:35 +01:00
ps3disk.c Merge branch 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block 2010-10-22 17:07:18 -07:00
ps3vram.c
rbd_types.h rbd: introduce rados block device (rbd), based on libceph 2010-10-20 15:38:13 -07:00
rbd.c rbd: handle online resize of underlying rbd image 2011-05-24 11:52:08 -07:00
smart1,2.h fix typos 'comamnd' -> 'command' in comments 2011-02-02 11:31:21 +01:00
sunvdc.c
swim3.c block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers 2011-04-21 21:33:05 +02:00
swim_asm.S
swim.c block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers 2011-04-21 21:33:05 +02:00
sx8.c
ub.c block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers 2011-04-21 21:33:05 +02:00
umem.c Merge branch 'for-2.6.39/stack-plug' into for-2.6.39/core 2011-03-10 08:58:35 +01:00
umem.h
viodasd.c Fix common misspellings 2011-03-31 11:26:23 -03:00
virtio_blk.c Merge branch 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block 2010-10-22 17:07:18 -07:00
xd.c
xd.h
xen-blkfront.c xen-blkfront: Introduce BLKIF_OP_FLUSH_DISKCACHE support. 2011-05-12 08:56:03 -04:00
xsysace.c block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers 2011-04-21 21:33:05 +02:00
z2ram.c drivers/block/z2ram.c: correct printing of sector_t 2010-10-28 06:15:26 -06:00