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Akash M a8b6a18b9b usb: gadget: f_fs: Remove WARN_ON in functionfs_bind
commit dfc51e48bc upstream.

This commit addresses an issue related to below kernel panic where
panic_on_warn is enabled. It is caused by the unnecessary use of WARN_ON
in functionsfs_bind, which easily leads to the following scenarios.

1.adb_write in adbd               2. UDC write via configfs
  =================	             =====================

->usb_ffs_open_thread()           ->UDC write
 ->open_functionfs()               ->configfs_write_iter()
  ->adb_open()                      ->gadget_dev_desc_UDC_store()
   ->adb_write()                     ->usb_gadget_register_driver_owner
                                      ->driver_register()
->StartMonitor()                       ->bus_add_driver()
 ->adb_read()                           ->gadget_bind_driver()
<times-out without BIND event>           ->configfs_composite_bind()
                                          ->usb_add_function()
->open_functionfs()                        ->ffs_func_bind()
 ->adb_open()                               ->functionfs_bind()
                                       <ffs->state !=FFS_ACTIVE>

The adb_open, adb_read, and adb_write operations are invoked from the
daemon, but trying to bind the function is a process that is invoked by
UDC write through configfs, which opens up the possibility of a race
condition between the two paths. In this race scenario, the kernel panic
occurs due to the WARN_ON from functionfs_bind when panic_on_warn is
enabled. This commit fixes the kernel panic by removing the unnecessary
WARN_ON.

Kernel panic - not syncing: kernel: panic_on_warn set ...
[   14.542395] Call trace:
[   14.542464]  ffs_func_bind+0x1c8/0x14a8
[   14.542468]  usb_add_function+0xcc/0x1f0
[   14.542473]  configfs_composite_bind+0x468/0x588
[   14.542478]  gadget_bind_driver+0x108/0x27c
[   14.542483]  really_probe+0x190/0x374
[   14.542488]  __driver_probe_device+0xa0/0x12c
[   14.542492]  driver_probe_device+0x3c/0x220
[   14.542498]  __driver_attach+0x11c/0x1fc
[   14.542502]  bus_for_each_dev+0x104/0x160
[   14.542506]  driver_attach+0x24/0x34
[   14.542510]  bus_add_driver+0x154/0x270
[   14.542514]  driver_register+0x68/0x104
[   14.542518]  usb_gadget_register_driver_owner+0x48/0xf4
[   14.542523]  gadget_dev_desc_UDC_store+0xf8/0x144
[   14.542526]  configfs_write_iter+0xf0/0x138

Fixes: ddf8abd259 ("USB: f_fs: the FunctionFS driver")
Cc: stable <stable@kernel.org>
Signed-off-by: Akash M <akash.m5@samsung.com>
Link: https://lore.kernel.org/r/20241219125221.1679-1-akash.m5@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-01-17 13:40:55 +01:00
arch x86/fpu: Ensure shadow stack is active before "getting" registers 2025-01-17 13:40:54 +01:00
block block: lift bio_is_zone_append to bio.h 2025-01-09 13:33:32 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: ecdsa - Avoid signed integer overflow on signature decoding 2024-12-14 20:03:36 +01:00
Documentation fs/writeback: convert wbc_account_cgroup_owner to take a folio 2025-01-17 13:40:33 +01:00
drivers usb: gadget: f_fs: Remove WARN_ON in functionfs_bind 2025-01-17 13:40:55 +01:00
fs fs: kill MNT_ONRB 2025-01-17 13:40:50 +01:00
include fs: kill MNT_ONRB 2025-01-17 13:40:50 +01:00
init Compiler Attributes: disable __counted_by for clang < 19.1.3 2024-12-05 14:02:45 +01:00
io_uring io_uring/sqpoll: zero sqd->thread on tctx errors 2025-01-17 13:40:52 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel sched_ext: idle: Refresh idle masks during idle-to-idle transitions 2025-01-17 13:40:49 +01:00
lib maple_tree: reload mas before the second call for mas_empty_area 2025-01-09 13:33:50 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm: hugetlb: independent PMD page table shared count 2025-01-09 13:33:54 +01:00
net rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy 2025-01-17 13:40:47 +01:00
rust rust: kbuild: set bindgen's Rust target version 2024-12-19 18:13:22 +01:00
samples samples/bpf: Fix a resource leak 2024-12-14 20:03:46 +01:00
scripts scripts/sorttable: fix orc_sort_cmp() to maintain symmetry and transitivity 2025-01-09 13:33:50 +01:00
security selinux: ignore unknown extended permissions 2025-01-09 13:33:32 +01:00
sound ASoC: mediatek: disable buffer pre-allocation 2025-01-17 13:40:36 +01:00
tools cgroup/cpuset: Prevent leakage of isolated CPUs into sched domains 2025-01-17 13:40:48 +01:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: x86: switch hugepage recovery thread to vhost_task 2024-12-05 14:02:43 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Kbuild updates for v6.12 2024-09-24 13:02:06 -07:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: update location of media main tree 2024-12-05 14:02:42 +01:00
Makefile Linux 6.12.9 2025-01-09 13:33:55 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.