[PATCH 5.10.y] mmc: via-sdmmc: cancel card-detect work on remove

[Sasha Levin <sashal@kernel.org>]

From: Fan Wu <fanwu01@zju.edu.cn>

[ Upstream commit 57e5d877f898d5e5c9d672a77bb6bdd24f0d9bf5 ]

Disabling the device interrupt and freeing the IRQ prevents new card-detect
work from being queued, but carddet_work already queued by the handler can
still run after via_sd_remove() returns. via_sdc_card_detect() recovers the
host through container_of() and dereferences its MMIO base; once remove()
returns the host can be freed, so that work would touch freed memory.

Cancel carddet_work after freeing the IRQ and before cancelling
finish_bh_work, which the card-detect handler can also queue. carddet_work
can re-enable the interrupt through via_reset_pcictrl(); mask it again
afterwards.

This issue was found by an in-house static analysis tool and confirmed by
manual code review.

Fixes: f0bf7f61b840 ("mmc: Add new via-sdmmc host controller driver")
Cc: stable@vger.kernel.org
Assisted-by: Codex:gpt-5.6
Signed-off-by: Fan Wu <fanwu01@zju.edu.cn>
Signed-off-by: Ulf Hansson <ulfh@kernel.org>
[ adjusted context to retain del_timer_sync() instead of timer_delete_sync(). ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/mmc/host/via-sdmmc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mmc/host/via-sdmmc.c b/drivers/mmc/host/via-sdmmc.c
index f6b525fb5c0ed..b75bd01422038 100644
--- a/drivers/mmc/host/via-sdmmc.c
+++ b/drivers/mmc/host/via-sdmmc.c
@@ -1205,6 +1205,10 @@ static void via_sd_remove(struct pci_dev *pcidev)
 
 	free_irq(pcidev->irq, sdhost);
 
+	cancel_work_sync(&sdhost->carddet_work);
+	/* carddet_work may re-enable the interrupt via via_reset_pcictrl(). */
+	writeb(0x0, sdhost->pcictrl_mmiobase + VIA_CRDR_PCIINTCTRL);
+
 	del_timer_sync(&sdhost->timer);
 
 	tasklet_kill(&sdhost->finish_tasklet);
-- 
2.53.0