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Filename Latest commit message Latest commit date
ChenXiaoSong b7e2b91fcb configfs: fix a race in configfs_{,un}register_subsystem()
[ Upstream commit 84ec758fb2daa236026506868c8796b0500c047d ]

When configfs_register_subsystem() or configfs_unregister_subsystem()
is executing link_group() or unlink_group(),
it is possible that two processes add or delete list concurrently.
Some unfortunate interleavings of them can cause kernel panic.

One of cases is:
A --> B --> C --> D
A <-- B <-- C <-- D

     delete list_head *B        |      delete list_head *C
--------------------------------|-----------------------------------
configfs_unregister_subsystem   |   configfs_unregister_subsystem
  unlink_group                  |     unlink_group
    unlink_obj                  |       unlink_obj
      list_del_init             |         list_del_init
        __list_del_entry        |           __list_del_entry
          __list_del            |             __list_del
            // next == C        |
            next->prev = prev   |
                                |               next->prev = prev
            prev->next = next   |
                                |                 // prev == B
                                |                 prev->next = next

Fix this by adding mutex when calling link_group() or unlink_group(),
but parent configfs_subsystem is NULL when config_item is root.
So I create a mutex configfs_subsystem_mutex.

Fixes: 7063fbf226 ("[PATCH] configfs: User-driven configuration filesystem")
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-03-02 11:41:10 +01:00
arch x86/fpu: Correct pkru/xstate inconsistency 2022-03-02 11:41:03 +01:00
block block/wbt: fix negative inflight counter when remove scsi device 2022-02-23 11:59:59 +01:00
certs
crypto
Documentation bpf: Add kconfig knob for disabling unpriv bpf by default 2022-02-16 12:52:49 +01:00
drivers spi: spi-zynq-qspi: Fix a NULL pointer dereference in zynq_qspi_exec_mem_op() 2022-03-02 11:41:10 +01:00
fs configfs: fix a race in configfs_{,un}register_subsystem() 2022-03-02 11:41:10 +01:00
include net: Force inlining of checksum functions in net/checksum.h 2022-03-02 11:41:08 +01:00
init bpf: Add kconfig knob for disabling unpriv bpf by default 2022-02-16 12:52:49 +01:00
ipc
kernel cgroup/cpuset: Fix a race between cpuset_attach() and cpu hotplug 2022-03-02 11:41:00 +01:00
lib lib/iov_iter: initialize "flags" in new pipe_buffer 2022-02-23 11:59:59 +01:00
LICENSES
mm
net netfilter: nf_tables: fix memory leak during stateful obj update 2022-03-02 11:41:09 +01:00
samples
scripts kconfig: fix failing to generate auto.conf 2022-02-23 12:00:01 +01:00
security ima: Do not print policy rule with inactive LSM labels 2022-02-16 12:52:47 +01:00
sound ASoC: ops: Fix stereo change notifications in snd_soc_put_volsw_range() 2022-02-23 11:59:58 +01:00
tools perf data: Fix double free in perf_session__delete() 2022-03-02 11:41:05 +01:00
usr
virt
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COPYING
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Makefile Linux 5.4.181 2022-02-23 12:00:01 +01:00
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 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.