kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-11-08 18:57:22 +00:00
Code Issues Releases Packages Activity
No description
1,383,744 commits 117 branches 5,824 tags 6.2 GiB
  • C 96.8%
  • Assembly 0.9%
  • Rust 0.7%
  • Shell 0.6%
  • Python 0.5%
  • Other 0.3%
Find a file
Duoming Zhou 6a92f57968 media: b2c2: Fix use-after-free causing by irq_check_work in flexcop_pci_remove 
commit 01e03fb7db upstream.

The original code uses cancel_delayed_work() in flexcop_pci_remove(), which
does not guarantee that the delayed work item irq_check_work has fully
completed if it was already running. This leads to use-after-free scenarios
where flexcop_pci_remove() may free the flexcop_device while irq_check_work
is still active and attempts to dereference the device.

A typical race condition is illustrated below:

CPU 0 (remove)                         | CPU 1 (delayed work callback)
flexcop_pci_remove()                   | flexcop_pci_irq_check_work()
  cancel_delayed_work()                |
  flexcop_device_kfree(fc_pci->fc_dev) |
                                       |   fc = fc_pci->fc_dev; // UAF

This is confirmed by a KASAN report:

==================================================================
BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x7d7/0x8c0
Write of size 8 at addr ffff8880093aa8c8 by task bash/135
...
Call Trace:
 <IRQ>
 dump_stack_lvl+0x55/0x70
 print_report+0xcf/0x610
 ? __run_timer_base.part.0+0x7d7/0x8c0
 kasan_report+0xb8/0xf0
 ? __run_timer_base.part.0+0x7d7/0x8c0
 __run_timer_base.part.0+0x7d7/0x8c0
 ? __pfx___run_timer_base.part.0+0x10/0x10
 ? __pfx_read_tsc+0x10/0x10
 ? ktime_get+0x60/0x140
 ? lapic_next_event+0x11/0x20
 ? clockevents_program_event+0x1d4/0x2a0
 run_timer_softirq+0xd1/0x190
 handle_softirqs+0x16a/0x550
 irq_exit_rcu+0xaf/0xe0
 sysvec_apic_timer_interrupt+0x70/0x80
 </IRQ>
...

Allocated by task 1:
 kasan_save_stack+0x24/0x50
 kasan_save_track+0x14/0x30
 __kasan_kmalloc+0x7f/0x90
 __kmalloc_noprof+0x1be/0x460
 flexcop_device_kmalloc+0x54/0xe0
 flexcop_pci_probe+0x1f/0x9d0
 local_pci_probe+0xdc/0x190
 pci_device_probe+0x2fe/0x470
 really_probe+0x1ca/0x5c0
 __driver_probe_device+0x248/0x310
 driver_probe_device+0x44/0x120
 __driver_attach+0xd2/0x310
 bus_for_each_dev+0xed/0x170
 bus_add_driver+0x208/0x500
 driver_register+0x132/0x460
 do_one_initcall+0x89/0x300
 kernel_init_freeable+0x40d/0x720
 kernel_init+0x1a/0x150
 ret_from_fork+0x10c/0x1a0
 ret_from_fork_asm+0x1a/0x30

Freed by task 135:
 kasan_save_stack+0x24/0x50
 kasan_save_track+0x14/0x30
 kasan_save_free_info+0x3a/0x60
 __kasan_slab_free+0x3f/0x50
 kfree+0x137/0x370
 flexcop_device_kfree+0x32/0x50
 pci_device_remove+0xa6/0x1d0
 device_release_driver_internal+0xf8/0x210
 pci_stop_bus_device+0x105/0x150
 pci_stop_and_remove_bus_device_locked+0x15/0x30
 remove_store+0xcc/0xe0
 kernfs_fop_write_iter+0x2c3/0x440
 vfs_write+0x871/0xd70
 ksys_write+0xee/0x1c0
 do_syscall_64+0xac/0x280
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
...

Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure
that the delayed work item is properly canceled and any executing delayed
work has finished before the device memory is deallocated.

This bug was initially identified through static analysis. To reproduce
and test it, I simulated the B2C2 FlexCop PCI device in QEMU and introduced
artificial delays within the flexcop_pci_irq_check_work() function to
increase the likelihood of triggering the bug.

Fixes: 382c5546d6 ("V4L/DVB (10694): [PATCH] software IRQ watchdog for Flexcop B2C2 DVB PCI cards")
Cc: stable@vger.kernel.org
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-10-06 11:20:05 +02:00
arch ARM fixes for 6.17 2025-09-28 13:24:43 -07:00
block blk-mq: fix blk_mq_tags double free while nr_requests grown 2025-10-06 11:20:04 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push fixes a NULL pointer dereference in ccp and a couple of 2025-09-19 09:58:21 -07:00
Documentation i2c-for-6.17-rc8 2025-09-28 13:19:23 -07:00
drivers media: b2c2: Fix use-after-free causing by irq_check_work in flexcop_pci_remove 2025-10-06 11:20:05 +02:00
fs 7 hotfixes. 4 are cc:stable and the remainder address post-6.16 issues or 2025-09-28 09:32:00 -07:00
include 7 hotfixes. 4 are cc:stable and the remainder address post-6.16 issues or 2025-09-28 09:32:00 -07:00
init kbuild: Disable CC_HAS_ASM_GOTO_OUTPUT on clang < 17 2025-09-24 09:29:15 +02:00
io_uring io_uring-6.17-20250919 2025-09-19 12:10:49 -07:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel tracing fixes for v6.17 2025-09-28 10:26:35 -07:00
lib hardening fixes for v6.17-rc4 2025-08-31 08:56:45 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm 7 hotfixes. 4 are cc:stable and the remainder address post-6.16 issues or 2025-09-28 09:32:00 -07:00
net nexthop: Forbid FDB status change while nexthop is in a group 2025-09-23 17:01:05 -07:00
rust Driver core fixes for 6.17-rc6 2025-09-13 10:36:06 -07:00
samples 15 hotfixes. 11 are cc:stable and the remainder address post-6.16 issues 2025-09-17 21:34:26 -07:00
scripts gcc-plugins: Remove TODO_verify_il for GCC >= 16 2025-10-06 11:20:04 +02:00
security + Features 2025-08-04 08:17:28 -07:00
sound ALSA: usb-audio: fix race condition to UAF in snd_usbmidi_free 2025-10-06 11:20:05 +02:00
tools Two fixes for rtla in v6.17: 2025-09-27 09:50:46 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge tag 'kvm-x86-no_assignment-6.17' of https://github.com/kvm-x86/linux into HEAD 2025-07-29 08:36:42 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +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 MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore gitignore: allow .pylintrc to be tracked 2025-07-02 17:10:04 -06:00
.mailmap 7 hotfixes. 4 are cc:stable and the remainder address post-6.16 issues or 2025-09-28 09:32:00 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.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: retire Boris from TLS maintainers 2025-08-26 17:36:01 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS i2c-for-6.17-rc8 2025-09-28 13:19:23 -07:00
Makefile Linux 6.17 2025-09-28 14:39:22 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

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.