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Chandana Kishori Chiluveru ed57b762f5 usb: gadget: configfs: Preserve function ordering after bind failure
commit 6cd0fe9138 upstream.

When binding the ConfigFS gadget to a UDC, the functions in each
configuration are added in list order. However, if usb_add_function()
fails, the failed function is put back on its configuration's
func_list and purge_configs_funcs() is called to further clean up.

purge_configs_funcs() iterates over the configurations and functions
in forward order, calling unbind() on each of the previously added
functions. But after doing so, each function gets moved to the
tail of the configuration's func_list. This results in reshuffling
the original order of the functions within a configuration such
that the failed function now appears first even though it may have
originally appeared in the middle or even end of the list. At this
point if the ConfigFS gadget is attempted to re-bind to the UDC,
the functions will be added in a different order than intended,
with the only recourse being to remove and relink the functions all
over again.

An example of this as follows:

ln -s functions/mass_storage.0 configs/c.1
ln -s functions/ncm.0 configs/c.1
ln -s functions/ffs.adb configs/c.1	# oops, forgot to start adbd
echo "<udc device>" > UDC		# fails
start adbd
echo "<udc device>" > UDC		# now succeeds, but...
					# bind order is
					# "ADB", mass_storage, ncm

[30133.118289] configfs-gadget gadget: adding 'Mass Storage Function'/ffffff810af87200 to config 'c'/ffffff817d6a2520
[30133.119875] configfs-gadget gadget: adding 'cdc_network'/ffffff80f48d1a00 to config 'c'/ffffff817d6a2520
[30133.119974] using random self ethernet address
[30133.120002] using random host ethernet address
[30133.139604] usb0: HOST MAC 3e:27:46:ba:3e:26
[30133.140015] usb0: MAC 6e:28:7e:42:66:6a
[30133.140062] configfs-gadget gadget: adding 'Function FS Gadget'/ffffff80f3868438 to config 'c'/ffffff817d6a2520
[30133.140081] configfs-gadget gadget: adding 'Function FS Gadget'/ffffff80f3868438 --> -19
[30133.140098] configfs-gadget gadget: unbind function 'Mass Storage Function'/ffffff810af87200
[30133.140119] configfs-gadget gadget: unbind function 'cdc_network'/ffffff80f48d1a00
[30133.173201] configfs-gadget a600000.dwc3: failed to start g1: -19
[30136.661933] init: starting service 'adbd'...
[30136.700126] read descriptors
[30136.700413] read strings
[30138.574484] configfs-gadget gadget: adding 'Function FS Gadget'/ffffff80f3868438 to config 'c'/ffffff817d6a2520
[30138.575497] configfs-gadget gadget: adding 'Mass Storage Function'/ffffff810af87200 to config 'c'/ffffff817d6a2520
[30138.575554] configfs-gadget gadget: adding 'cdc_network'/ffffff80f48d1a00 to config 'c'/ffffff817d6a2520
[30138.575631] using random self ethernet address
[30138.575660] using random host ethernet address
[30138.595338] usb0: HOST MAC 2e:cf:43💿ca:c8
[30138.597160] usb0: MAC 6a:f0:9f:ee:82:a0
[30138.791490] configfs-gadget gadget: super-speed config #1: c

Fix this by reversing the iteration order of the functions in
purge_config_funcs() when unbinding them, and adding them back to
the config's func_list at the head instead of the tail. This
ensures that we unbind and unwind back to the original list order.

Fixes: 88af8bbe4e ("usb: gadget: the start of the configfs interface")
Signed-off-by: Chandana Kishori Chiluveru <cchiluve@codeaurora.org>
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Link: https://lore.kernel.org/r/20201229224443.31623-1-jackp@codeaurora.org
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-12 20:18:21 +01:00
arch powerpc: Handle .text.{hot,unlikely}.* in linker script 2021-01-12 20:18:17 +01:00
block scsi: block: Do not accept any requests while suspended 2021-01-12 20:18:17 +01:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto crypto: asym_tpm: correct zero out potential secrets 2021-01-12 20:18:17 +01:00
Documentation dt-bindings: rtc: add reset-source property 2021-01-09 13:46:22 +01:00
drivers usb: gadget: configfs: Preserve function ordering after bind failure 2021-01-12 20:18:21 +01:00
fs exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:46:24 +01:00
include scsi: block: Do not accept any requests while suspended 2021-01-12 20:18:17 +01:00
init exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:46:24 +01:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel workqueue: Kick a worker based on the actual activation of delayed works 2021-01-12 20:18:14 +01:00
lib lib/genalloc: fix the overflow when size is too big 2021-01-12 20:18:16 +01:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm: memmap defer init doesn't work as expected 2021-01-06 14:56:50 +01:00
net erspan: fix version 1 check in gre_parse_header() 2021-01-12 20:18:12 +01:00
samples samples/bpf: Fix possible hang in xdpsock with multiple threads 2020-12-30 11:53:49 +01:00
scripts depmod: handle the case of /sbin/depmod without /sbin in PATH 2021-01-12 20:18:16 +01:00
security ima: Don't modify file descriptor mode on the fly 2020-12-30 11:54:17 +01:00
sound ALSA: usb-audio: Fix UBSAN warnings for MIDI jacks 2021-01-12 20:18:20 +01:00
tools selftests/vm: fix building protection keys test 2021-01-12 20:18:14 +01:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt kvm: x86/mmu: Support dirty logging for the TDP MMU 2020-10-23 03:42:13 -04:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-12-10 15:30:13 -08:00
Makefile kbuild: don't hardcode depmod path 2021-01-12 20:18:16 +01:00
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.