6bb0f10966
[ Upstream commit 6a0c054930d554ad8f8044ef1fc856d9da391c81 ]
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>
Link: https://lore.kernel.org/r/20220710103002.63283-1-duoming@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>