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| author | Duoming Zhou <duoming@zju.edu.cn> | 2023-08-02 11:37:37 +0800 |
|---|---|---|
| committer | John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> | 2023-09-09 21:54:20 +0200 |
| commit | 246f80a0b17f8f582b2c0996db02998239057c65 (patch) | |
| tree | 8432172e981912d3e73af3b8c185049424b11202 /arch/sh | |
| parent | fb60211f377b69acffead3147578f86d0092a7a5 (diff) | |
| download | lwn-246f80a0b17f8f582b2c0996db02998239057c65.tar.gz lwn-246f80a0b17f8f582b2c0996db02998239057c65.zip | |
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: 9f5e8eee5cfe ("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>
Diffstat (limited to 'arch/sh')
| -rw-r--r-- | arch/sh/drivers/push-switch.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/sh/drivers/push-switch.c b/arch/sh/drivers/push-switch.c index c95f48ff3f6f..6ecba5f521eb 100644 --- a/arch/sh/drivers/push-switch.c +++ b/arch/sh/drivers/push-switch.c @@ -101,8 +101,8 @@ static int switch_drv_remove(struct platform_device *pdev) device_remove_file(&pdev->dev, &dev_attr_switch); platform_set_drvdata(pdev, NULL); - flush_work(&psw->work); timer_shutdown_sync(&psw->debounce); + flush_work(&psw->work); free_irq(irq, pdev); kfree(psw); |