Gao Xiang fd4c7fe100 staging: erofs: fix use-after-free of on-stack `z_erofs_vle_unzip_io'
[ Upstream commit 848bd9acdc ]

The root cause is the race as follows:
 Thread #0                         Thread #1

 z_erofs_vle_unzip_kickoff         z_erofs_submit_and_unzip

                                    struct z_erofs_vle_unzip_io io[]
   atomic_add_return()
                                    wait_event()
                                    [end of function]
   wake_up()

Fix it by taking the waitqueue lock between atomic_add_return and
wake_up to close such the race.

kernel message:

Unable to handle kernel paging request at virtual address 97f7052caa1303dc
...
Workqueue: kverityd verity_work
task: ffffffe32bcb8000 task.stack: ffffffe3298a0000
PC is at __wake_up_common+0x48/0xa8
LR is at __wake_up+0x3c/0x58
...
Call trace:
...
[<ffffff94a08ff648>] __wake_up_common+0x48/0xa8
[<ffffff94a08ff8b8>] __wake_up+0x3c/0x58
[<ffffff94a0c11b60>] z_erofs_vle_unzip_kickoff+0x40/0x64
[<ffffff94a0c118e4>] z_erofs_vle_read_endio+0x94/0x134
[<ffffff94a0c83c9c>] bio_endio+0xe4/0xf8
[<ffffff94a1076540>] dec_pending+0x134/0x32c
[<ffffff94a1076f28>] clone_endio+0x90/0xf4
[<ffffff94a0c83c9c>] bio_endio+0xe4/0xf8
[<ffffff94a1095024>] verity_work+0x210/0x368
[<ffffff94a08c4150>] process_one_work+0x188/0x4b4
[<ffffff94a08c45bc>] worker_thread+0x140/0x458
[<ffffff94a08cad48>] kthread+0xec/0x108
[<ffffff94a0883ab4>] ret_from_fork+0x10/0x1c
Code: d1006273 54000260 f9400804 b9400019 (b85fc081)
---[ end trace be9dde154f677cd1 ]---

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-01-26 09:32:38 +01:00
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2019-01-22 21:40:38 +01:00
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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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.
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