linux/drivers/block
Zhiqiang Liu c8ab422553 brd: check and limit max_part par
In brd_init func, rd_nr num of brd_device are firstly allocated
and add in brd_devices, then brd_devices are traversed to add each
brd_device by calling add_disk func. When allocating brd_device,
the disk->first_minor is set to i * max_part, if rd_nr * max_part
is larger than MINORMASK, two different brd_device may have the same
devt, then only one of them can be successfully added.
when rmmod brd.ko, it will cause oops when calling brd_exit.

Follow those steps:
  # modprobe brd rd_nr=3 rd_size=102400 max_part=1048576
  # rmmod brd
then, the oops will appear.

Oops log:
[  726.613722] Call trace:
[  726.614175]  kernfs_find_ns+0x24/0x130
[  726.614852]  kernfs_find_and_get_ns+0x44/0x68
[  726.615749]  sysfs_remove_group+0x38/0xb0
[  726.616520]  blk_trace_remove_sysfs+0x1c/0x28
[  726.617320]  blk_unregister_queue+0x98/0x100
[  726.618105]  del_gendisk+0x144/0x2b8
[  726.618759]  brd_exit+0x68/0x560 [brd]
[  726.619501]  __arm64_sys_delete_module+0x19c/0x2a0
[  726.620384]  el0_svc_common+0x78/0x130
[  726.621057]  el0_svc_handler+0x38/0x78
[  726.621738]  el0_svc+0x8/0xc
[  726.622259] Code: aa0203f6 aa0103f7 aa1e03e0 d503201f (7940e260)

Here, we add brd_check_and_reset_par func to check and limit max_part par.

--
V5->V6:
 - remove useless code

V4->V5:(suggested by Ming Lei)
 - make sure max_part is not larger than DISK_MAX_PARTS

V3->V4:(suggested by Ming Lei)
 - remove useless change
 - add one limit of max_part

V2->V3: (suggested by Ming Lei)
 - clear .minors when running out of consecutive minor space in brd_alloc
 - remove limit of rd_nr

V1->V2:
 - add more checks in brd_check_par_valid as suggested by Ming Lei.

Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-04 07:19:33 -07:00
..
aoe block: aoe: Fix kernel crash due to atomic sleep when exiting 2019-08-08 07:29:02 -06:00
drbd drbd: fifo_alloc() should use struct_size 2020-01-29 21:03:33 -07:00
mtip32xx block: mtip32xx: Spelling s/configration/configuration/ 2019-10-25 14:31:07 -06:00
paride paride/pcd: need to check if cd->disk is null in pcd_detect 2019-09-04 07:04:37 -06:00
rsxx rsxx: add missed destroy_workqueue calls in remove 2019-11-14 13:59:49 -07:00
xen-blkback xen: branch for v5.5-rc3 2019-12-21 06:24:56 -08:00
zram zram: fix race between backing_dev_show and backing_dev_store 2019-10-19 06:32:32 -04:00
amiflop.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
ataflop.c ataflop: Remove unneeded semicolon 2019-11-28 10:40:47 -07:00
brd.c brd: check and limit max_part par 2020-02-04 07:19:33 -07:00
cryptoloop.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 30 2019-05-24 17:27:10 +02:00
floppy.c floppy: fix usercopy direction 2019-08-09 07:41:36 -06:00
Kconfig docs: blockdev: add it to the admin-guide 2019-07-15 11:03:01 -03:00
loop.c block: remove (__)blkdev_reread_part as an exported API 2019-11-14 07:43:59 -07:00
loop.h block/loop: Use global lock for ioctl() operation. 2018-11-08 06:30:11 -07:00
Makefile drivers/block: Remove DAC960 driver 2018-10-17 09:42:30 -06:00
nbd.c nbd: add a flush_workqueue in nbd_start_device 2020-01-29 21:05:53 -07:00
null_blk_main.c null_blk: remove unused variable warning on !CONFIG_BLK_DEV_ZONED 2019-12-04 09:17:41 -07:00
null_blk_zoned.c null_blk: Fix zone write handling 2020-01-15 08:18:39 -07:00
null_blk.h block: rework zone reporting 2019-11-12 19:12:07 -07:00
pktcdvd.c pktcdvd: fix regression on 64-bit architectures 2019-12-21 07:25:50 -07:00
ps3disk.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 164 2019-05-30 11:26:38 -07:00
ps3vram.c block/ps3vram: Use %llu to format sector_t after LBDAF removal 2019-06-13 03:17:50 -06:00
rbd_types.h rbd: support for object-map and fast-diff 2019-07-08 14:01:45 +02:00
rbd.c libceph, rbd, ceph: convert to use the new mount API 2019-11-27 22:28:37 +01:00
skd_main.c Linux 5.2-rc6 2019-07-01 08:16:08 -06:00
skd_s1120.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
sunvdc.c block: sunvdc: Remove unneeded semicolon 2019-11-28 10:40:46 -07:00
swim3.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
swim_asm.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
swim.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sx8.c sx8: use a per-host tag_set 2018-11-09 08:14:14 -07:00
umem.c remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
umem.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 348 2019-06-05 17:37:08 +02:00
virtio_blk.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
xen-blkfront.c xen/blkfront: limit allocated memory size to actual use case 2020-01-29 21:13:18 -07:00
xsysace.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
z2ram.c powerpc updates for 4.20 2018-10-26 14:36:21 -07:00