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    SubjectRe: [PATCH v2] staging: rtl8192u: Fix sleep in atomic context bug in dm_fsync_timer_callback
    On Sat, Jun 25, 2022 at 05:21:06PM +0800, duoming@zju.edu.cn wrote:
    > Hello,
    >
    > > > On Thu, Jun 23, 2022 at 01:59:12PM +0800, Duoming Zhou wrote:
    > > > > 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: 8fc8598e61f6 ("Staging: Added Realtek rtl8192u driver to staging")
    > > > > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
    > > > > ---
    > > > > Changes in v2:
    > > > > - Use delayed work to replace timer.
    > > >
    > > > Did you test this with real hardware to verify it still works?
    > >
    > > I am testing this and I will give you feedback within one or two days.
    >
    > Do you know what vendor id and device id use the r8192u_usb driver?

    The vendor/device ids are in the driver itself. Also in the output of
    modinfo:
    ❯ modinfo drivers/staging/rtl8192u/r8192u_usb.ko | grep alias
    alias: usb:v043Ep7A01d*dc*dsc*dp*ic*isc*ip*in*
    alias: usb:v5A57p0290d*dc*dsc*dp*ic*isc*ip*in*
    alias: usb:v2001p3301d*dc*dsc*dp*ic*isc*ip*in*
    alias: usb:v1740p9201d*dc*dsc*dp*ic*isc*ip*in*
    alias: usb:v0DF6p0031d*dc*dsc*dp*ic*isc*ip*in*
    alias: usb:v050Dp805Ed*dc*dsc*dp*ic*isc*ip*in*
    alias: usb:v07AAp0043d*dc*dsc*dp*ic*isc*ip*in*
    alias: usb:v0BDAp8709d*dc*dsc*dp*ic*isc*ip*in*

    see the "v" and "p" portions of the alias string.

    thanks,

    greg k-h

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