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Xinyong 1a087f0321 usb: gadget: f_fs: Fix use-after-free in ffs_fs_kill_sb()
When I debug a kernel crash issue in funcitonfs, found ffs_data.ref
overflowed, While functionfs is unmounting, ffs_data is put twice.

Commit 43938613c6 ("drivers, usb: convert ffs_data.ref from atomic_t to
refcount_t") can avoid refcount overflow, but that is risk some situations.
So no need put ffs data in ffs_fs_kill_sb, already put in ffs_data_closed.

The issue can be reproduced in Mediatek mt6763 SoC, ffs for ADB device.
KASAN enabled configuration reports use-after-free errro.

BUG: KASAN: use-after-free in refcount_dec_and_test+0x14/0xe0 at addr ffffffc0579386a0
Read of size 4 by task umount/4650
====================================================
BUG kmalloc-512 (Tainted: P        W  O   ): kasan: bad access detected
-----------------------------------------------------------------------------

INFO: Allocated in ffs_fs_mount+0x194/0x844 age=22856 cpu=2 pid=566
    alloc_debug_processing+0x1ac/0x1e8
    ___slab_alloc.constprop.63+0x640/0x648
    __slab_alloc.isra.57.constprop.62+0x24/0x34
    kmem_cache_alloc_trace+0x1a8/0x2bc
    ffs_fs_mount+0x194/0x844
    mount_fs+0x6c/0x1d0
    vfs_kern_mount+0x50/0x1b4
    do_mount+0x258/0x1034
INFO: Freed in ffs_data_put+0x25c/0x320 age=0 cpu=3 pid=4650
    free_debug_processing+0x22c/0x434
    __slab_free+0x2d8/0x3a0
    kfree+0x254/0x264
    ffs_data_put+0x25c/0x320
    ffs_data_closed+0x124/0x15c
    ffs_fs_kill_sb+0xb8/0x110
    deactivate_locked_super+0x6c/0x98
    deactivate_super+0xb0/0xbc
INFO: Object 0xffffffc057938600 @offset=1536 fp=0x          (null)
......
Call trace:
[<ffffff900808cf5c>] dump_backtrace+0x0/0x250
[<ffffff900808d3a0>] show_stack+0x14/0x1c
[<ffffff90084a8c04>] dump_stack+0xa0/0xc8
[<ffffff900826c2b4>] print_trailer+0x158/0x260
[<ffffff900826d9d8>] object_err+0x3c/0x40
[<ffffff90082745f0>] kasan_report_error+0x2a8/0x754
[<ffffff9008274f84>] kasan_report+0x5c/0x60
[<ffffff9008273208>] __asan_load4+0x70/0x88
[<ffffff90084cd81c>] refcount_dec_and_test+0x14/0xe0
[<ffffff9008d98f9c>] ffs_data_put+0x80/0x320
[<ffffff9008d9d904>] ffs_fs_kill_sb+0xc8/0x110
[<ffffff90082852a0>] deactivate_locked_super+0x6c/0x98
[<ffffff900828537c>] deactivate_super+0xb0/0xbc
[<ffffff90082af0c0>] cleanup_mnt+0x64/0xec
[<ffffff90082af1b0>] __cleanup_mnt+0x10/0x18
[<ffffff90080d9e68>] task_work_run+0xcc/0x124
[<ffffff900808c8c0>] do_notify_resume+0x60/0x70
[<ffffff90080866e4>] work_pending+0x10/0x14

Cc: stable@vger.kernel.org
Signed-off-by: Xinyong <xinyong.fang@linux.alibaba.com>

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
2018-03-05 10:42:53 +02:00
arch Xtensa fixes for 4.16 2018-02-25 17:02:24 -08:00
block treewide/trivial: Remove ';;$' typo noise 2018-02-22 10:59:33 +01:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto X.509: fix NULL dereference when restricting key with unsupported_sig 2018-02-22 14:38:34 +00:00
Documentation Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-02-25 16:58:55 -08:00
drivers usb: gadget: f_fs: Fix use-after-free in ffs_fs_kill_sb() 2018-03-05 10:42:53 +02:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs NFS client bugfixes for Linux 4.16 2018-02-25 13:43:18 -08:00
include Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-02-25 16:29:59 -08:00
init membarrier: Provide core serializing command, *_SYNC_CORE 2018-02-05 21:35:03 +01:00
ipc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
kernel Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-02-25 16:58:55 -08:00
lib Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk 2018-02-23 14:57:20 -08:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm mm: don't defer struct page initialization for Xen pv guests 2018-02-21 15:35:43 -08:00
net net_sched: gen_estimator: fix broken estimators based on percpu stats 2018-02-23 12:35:46 -05:00
samples sample/bpf: fix erspan metadata 2018-02-06 11:32:49 -05:00
scripts Kbuild updates for v4.16 (2nd) 2018-02-09 19:32:41 -08:00
security integrity/security: fix digsig.c build error with header file 2018-02-22 20:09:08 -08:00
sound ALSA: hda/realtek: PCI quirk for Fujitsu U7x7 2018-02-14 12:02:26 +01:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-23 15:14:17 -08:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: ignore ASN.1 auto generated files 2018-02-14 21:05:38 +01:00
.mailmap mailmap: update Mark Yao's email address 2018-01-04 16:45:09 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS MAINTAINERS: Remove Richard Purdie from LED maintainers 2018-02-19 20:23:49 +01:00
Makefile Linux 4.16-rc3 2018-02-25 18:50:41 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

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.