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Subject[PATCH] hwmon: (xgene) Fix use after free bug in xgene_hwmon_remove due to race condition
Date
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 make cleanup, there may
be a unfinished work.

The possiblesequence is as follows:

Fix it by finishing the work before cleanup in the
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: 2ca492e22cb7 ("hwmon: (xgene) Fix crash when alarm occurs before driver probe")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
---
drivers/hwmon/xgene-hwmon.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/hwmon/xgene-hwmon.c b/drivers/hwmon/xgene-hwmon.c
index 5cde837bfd09..d1abea49f01b 100644
--- a/drivers/hwmon/xgene-hwmon.c
+++ b/drivers/hwmon/xgene-hwmon.c
@@ -761,6 +761,7 @@ 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)
--
2.25.1
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