linux/arch/sh/drivers
Duoming Zhou 246f80a0b1 sh: push-switch: Reorder cleanup operations to avoid use-after-free bug
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: 9f5e8eee5c ("sh: generic push-switch framework.")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/20230802033737.9738-1-duoming@zju.edu.cn
Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
2023-09-09 21:54:20 +02:00
..
dma sh updates for v6.5 2023-07-05 21:45:32 -07:00
pci sh updates for v6.4 2023-04-27 17:41:23 -07:00
superhyway sh: drivers: convert to SPDX identifiers 2018-12-28 12:11:44 -08:00
heartbeat.c remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile drivers: move the early platform device support to arch/sh 2019-10-07 13:50:47 +02:00
platform_early.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
push-switch.c sh: push-switch: Reorder cleanup operations to avoid use-after-free bug 2023-09-09 21:54:20 +02:00