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Yufen Yu 77c301287e scsi: core: try to get module before removing device
We have a test case like block/001 in blktests, which will create a scsi
device by loading scsi_debug module and then try to delete the device by
sysfs interface. At the same time, it may remove the scsi_debug module.

And getting a invalid paging request BUG_ON as following:

[   34.625854] BUG: unable to handle page fault for address: ffffffffa0016bb8
[   34.629189] Oops: 0000 [#1] SMP PTI
[   34.629618] CPU: 1 PID: 450 Comm: bash Tainted: G        W         5.4.0-rc3+ #473
[   34.632524] RIP: 0010:scsi_proc_hostdir_rm+0x5/0xa0
[   34.643555] CR2: ffffffffa0016bb8 CR3: 000000012cd88000 CR4: 00000000000006e0
[   34.644545] Call Trace:
[   34.644907]  scsi_host_dev_release+0x6b/0x1f0
[   34.645511]  device_release+0x74/0x110
[   34.646046]  kobject_put+0x116/0x390
[   34.646559]  put_device+0x17/0x30
[   34.647041]  scsi_target_dev_release+0x2b/0x40
[   34.647652]  device_release+0x74/0x110
[   34.648186]  kobject_put+0x116/0x390
[   34.648691]  put_device+0x17/0x30
[   34.649157]  scsi_device_dev_release_usercontext+0x2e8/0x360
[   34.649953]  execute_in_process_context+0x29/0x80
[   34.650603]  scsi_device_dev_release+0x20/0x30
[   34.651221]  device_release+0x74/0x110
[   34.651732]  kobject_put+0x116/0x390
[   34.652230]  sysfs_unbreak_active_protection+0x3f/0x50
[   34.652935]  sdev_store_delete.cold.4+0x71/0x8f
[   34.653579]  dev_attr_store+0x1b/0x40
[   34.654103]  sysfs_kf_write+0x3d/0x60
[   34.654603]  kernfs_fop_write+0x174/0x250
[   34.655165]  __vfs_write+0x1f/0x60
[   34.655639]  vfs_write+0xc7/0x280
[   34.656117]  ksys_write+0x6d/0x140
[   34.656591]  __x64_sys_write+0x1e/0x30
[   34.657114]  do_syscall_64+0xb1/0x400
[   34.657627]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   34.658335] RIP: 0033:0x7f156f337130

During deleting scsi target, the scsi_debug module have been removed. Then,
sdebug_driver_template belonged to the module cannot be accessd, resulting
in scsi_proc_hostdir_rm() BUG_ON.

To fix the bug, we add scsi_device_get() in sdev_store_delete() to try to
increase refcount of module, avoiding the module been removed.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20191015130556.18061-1-yuyufen@huawei.com
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2019-10-17 21:57:09 -04:00
arch scsi: arm64: dts: qcom: sdm845: Specify UFS device-reset GPIO 2019-09-07 16:36:03 -04:00
block docs conversion for v5.3-rc1 2019-07-16 12:21:41 -07:00
certs Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
crypto USB / PHY patches for 5.3-rc1 2019-07-11 15:40:06 -07:00
Documentation scsi: ufs-qcom: Implement device_reset vops 2019-09-07 16:36:03 -04:00
drivers scsi: core: try to get module before removing device 2019-10-17 21:57:09 -04:00
fs SMB3 fixes: two fixes for stable, one that had dependency on earlier patch in this merge window and can now go in, and a perf improvement in SMB3 open 2019-07-21 10:01:17 -07:00
include scsi: core: save/restore command resid for error handling 2019-10-03 21:43:04 -04:00
init Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
ipc Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
kernel dma-mapping fixes for 5.3-rc1 2019-07-20 12:09:52 -07:00
lib Kbuild updates for v5.3 (2nd) 2019-07-20 09:34:55 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
net Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-07-19 10:06:06 -07:00
scripts Kbuild updates for v5.3 (2nd) 2019-07-20 09:34:55 -07:00
security Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
sound sound fixes for 5.3-rc1 2019-07-18 09:36:51 -07:00
tools New feature to add support for NTB virtual MSI interrupts, the ability 2019-07-21 09:46:59 -07:00
usr Kbuild updates for v5.3 (2nd) 2019-07-20 09:34:55 -07:00
virt KVM: Boost vCPUs that are delivering interrupts 2019-07-20 09:00:45 +02:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: create *.mod with full directory path and remove MODVERDIR 2019-07-18 02:19:31 +09:00
.mailmap MAINTAINERS: Update my email address 2019-06-18 14:37:27 +01:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Remove references to dead website. 2019-07-19 12:22:04 -07:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS scsi: MAINTAINERS: Update qla2xxx driver 2019-10-03 21:48:06 -04:00
Makefile Linus 5.3-rc1 2019-07-21 14:05:38 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.