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hwmon: (xgene) Fix use after free bug in xgene_hwmon_remove due to race condition

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[ Upstream commit cb090e64cf25602b9adaf32d5dfc9c8bec493cd1 ]

In xgene_hwmon_probe, &ctx->workq is bound with xgene_hwmon_evt_work.
Then it will be started.

If we remove the driver which will call xgene_hwmon_remove to clean up,
there may be unfinished work.

The possible sequence is as follows:

Fix it by finishing the work before cleanup in xgene_hwmon_remove.

CPU0                  CPU1

                    |xgene_hwmon_evt_work
xgene_hwmon_remove   |
kfifo_free(&ctx->async_msg_fifo);|
                    |
                    |kfifo_out_spinlocked
                    |//use &ctx->async_msg_fifo
Fixes: 2ca492e22c ("hwmon: (xgene) Fix crash when alarm occurs before driver probe")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Link: https://lore.kernel.org/r/20230310084007.1403388-1-zyytlz.wz@163.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Zheng Wang 2023-03-10 16:40:07 +08:00 committed by Greg Kroah-Hartman
parent 55d01536a2
commit e0a37b43cd
1 changed files with 1 additions and 0 deletions
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1
drivers/hwmon/xgene-hwmon.c
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@ -780,6 +780,7 @@ static int xgene_hwmon_remove(struct platform_device *pdev)
{
struct xgene_hwmon_dev *ctx = platform_get_drvdata(pdev);
cancel_work_sync(&ctx->workq);
hwmon_device_unregister(ctx->hwmon_dev);
kfifo_free(&ctx->async_msg_fifo);
if (acpi_disabled)