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6a0c054930
There are sleep in atomic context bugs when dm_fsync_timer_callback is
executing. The root cause is that the memory allocation functions with
GFP_KERNEL or GFP_NOIO parameters are called in dm_fsync_timer_callback
which is a timer handler. The call paths that could trigger bugs are
shown below:
(interrupt context)
dm_fsync_timer_callback
write_nic_byte
kzalloc(sizeof(data), GFP_KERNEL); //may sleep
usb_control_msg
kmalloc(.., GFP_NOIO); //may sleep
write_nic_dword
kzalloc(sizeof(data), GFP_KERNEL); //may sleep
usb_control_msg
kmalloc(.., GFP_NOIO); //may sleep
This patch uses delayed work to replace timer and moves the operations
that may sleep into the delayed work in order to mitigate bugs.
Fixes: 8fc8598e61 ("Staging: Added Realtek rtl8192u driver to staging")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20220710103002.63283-1-duoming@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.