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Filename Latest commit message Latest commit date
Yang Yingliang 82867190ce w1: fix deadloop in __w1_remove_master_device()
[ Upstream commit 25d5648802f12ae486076ceca5d7ddf1fef792b2 ]

I got a deadloop report while doing device(ds2482) add/remove test:

  [  162.241881] w1_master_driver w1_bus_master1: Waiting for w1_bus_master1 to become free: refcnt=1.
  [  163.272251] w1_master_driver w1_bus_master1: Waiting for w1_bus_master1 to become free: refcnt=1.
  [  164.296157] w1_master_driver w1_bus_master1: Waiting for w1_bus_master1 to become free: refcnt=1.
  ...

__w1_remove_master_device() can't return, because the dev->refcnt is not zero.

w1_add_master_device()			|
  w1_alloc_dev()			|
    atomic_set(&dev->refcnt, 2)		|
  kthread_run()				|
					|__w1_remove_master_device()
					|  kthread_stop()
  // KTHREAD_SHOULD_STOP is set,	|
  // threadfn(w1_process) won't be	|
  // called.				|
  kthread()				|
					|  // refcnt will never be 0, it's deadloop.
					|  while (atomic_read(&dev->refcnt)) {...}

After calling w1_add_master_device(), w1_process() is not really
invoked, before w1_process() starting, if kthread_stop() is called
in __w1_remove_master_device(), w1_process() will never be called,
the refcnt can not be decreased, then it causes deadloop in remove
function because of non-zero refcnt.

We need to make sure w1_process() is really started, so move the
set refcnt into w1_process() to fix this problem.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20221205080434.3149205-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-06 07:52:40 +01:00
arch ARM: imx: add missing of_node_put() 2023-02-06 07:52:35 +01:00
block blk-mq: fix possible memleak when register 'hctx' failed 2023-01-18 11:41:38 +01:00
certs
crypto crypto: tcrypt - Fix multibuffer skcipher speed test mem leak 2023-01-18 11:41:19 +01:00
Documentation dt-bindings: phy: g12a-usb3-pcie-phy: fix compatible string documentation 2023-01-24 07:18:01 +01:00
drivers w1: fix deadloop in __w1_remove_master_device() 2023-02-06 07:52:40 +01:00
fs affs: initialize fsdata in affs_truncate() 2023-02-06 07:52:36 +01:00
include l2tp: Serialize access to sk_user_data with sk_callback_lock 2023-02-06 07:52:37 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-08 11:22:59 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel bpf: Fix pointer-leak due to insufficient speculative store bypass mitigation 2023-02-06 07:52:36 +01:00
lib mm/highmem: Lift memcpy_[to|from]_page to core 2023-01-18 11:41:55 +01:00
LICENSES
mm mm/khugepaged: fix collapse_pte_mapped_thp() to allow anon_vma 2023-01-24 07:18:01 +01:00
net tcp: avoid the lookup process failing to get sk in ehash table 2023-02-06 07:52:40 +01:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2023-01-18 11:41:26 +01:00
scripts scripts/faddr2line: Fix regression in name resolution on ppc64le 2022-12-08 11:23:02 +01:00
security tomoyo: fix broken dependency on *.conf.default 2023-02-06 07:52:35 +01:00
sound ALSA: hda/realtek - Turn on power early 2023-01-24 07:17:59 +01:00
tools selftests/bpf: check null propagation only neither reg is PTR_TO_BTF_ID 2023-01-24 07:17:58 +01:00
usr
virt KVM: arm64: vgic: Fix exit condition in scan_its_table() 2022-10-29 10:20:35 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: add Chandan as xfs maintainer for 5.4.y 2022-09-28 11:03:58 +02:00
Makefile Linux 5.4.230 2023-01-24 07:18:01 +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.