246f80a0b1
The original code puts flush_work() before timer_shutdown_sync()
in switch_drv_remove(). Although we use flush_work() to stop
the worker, it could be rescheduled in switch_timer(). As a result,
a use-after-free bug can occur. The details are shown below:
(cpu 0) | (cpu 1)
switch_drv_remove() |
flush_work() |
... | switch_timer // timer
| schedule_work(&psw->work)
timer_shutdown_sync() |
... | switch_work_handler // worker
kfree(psw) // free |
| psw->state = 0 // use
This patch puts timer_shutdown_sync() before flush_work() to
mitigate the bugs. As a result, the worker and timer will be
stopped safely before the deallocate operations.
Fixes:
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.. | ||
boards | ||
boot | ||
cchips | ||
configs | ||
drivers | ||
include | ||
kernel | ||
lib | ||
math-emu | ||
mm | ||
tools | ||
Kbuild | ||
Kconfig | ||
Kconfig.cpu | ||
Kconfig.debug | ||
Makefile |