He, Bo cef0d4948c HID: debug: fix race condition with between rdesc_show() and device removal
There is a race condition that could happen if hid_debug_rdesc_show()
is running while hdev is in the process of going away (device removal,
system suspend, etc) which could result in NULL pointer dereference:

	 BUG: unable to handle kernel paging request at 0000000783316040
	 CPU: 1 PID: 1512 Comm: getevent Tainted: G     U     O 4.19.20-quilt-2e5dc0ac-00029-gc455a447dd55 #1
	 RIP: 0010:hid_dump_device+0x9b/0x160
	 Call Trace:
	  hid_debug_rdesc_show+0x72/0x1d0
	  seq_read+0xe0/0x410
	  full_proxy_read+0x5f/0x90
	  __vfs_read+0x3a/0x170
	  vfs_read+0xa0/0x150
	  ksys_read+0x58/0xc0
	  __x64_sys_read+0x1a/0x20
	  do_syscall_64+0x55/0x110
	  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Grab driver_input_lock to make sure the input device exists throughout the
whole process of dumping the rdesc.

[jkosina@suse.cz: update changelog a bit]
Signed-off-by: he, bo <bo.he@intel.com>
Signed-off-by: "Zhang, Jun" <jun.zhang@intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2019-03-19 15:41:08 +01:00
2019-02-15 09:12:28 -08:00
2019-03-07 18:32:03 -08:00
2019-03-07 12:20:11 -08:00
2019-03-06 13:33:11 -08:00
2019-02-21 11:41:19 +00:00
2019-03-06 14:18:59 -08:00
2019-03-06 14:52:48 -08:00

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.
Description
Linux kernel stable tree
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