From: Qiang Yu quic_qianyu@quicinc.com
[ Upstream commit 869a99907faea6d1835b0bd0d0422ae3519c6ea9 ]
There is a race condition where mhi_prepare_channel() updates the read and write pointers as the base address and in parallel, if an M0 transition occurs, the tasklet goes ahead and rings doorbells for all channels with a delta in TRE rings assuming they are already enabled. This causes a null pointer access. Fix it by adding a channel enabled check before ringing channel doorbells.
Cc: stable@vger.kernel.org # 5.19 Fixes: a6e2e3522f29 "bus: mhi: core: Add support for PM state transitions" Signed-off-by: Qiang Yu quic_qianyu@quicinc.com Reviewed-by: Manivannan Sadhasivam mani@kernel.org Link: https://lore.kernel.org/r/1665889532-13634-1-git-send-email-quic_qianyu@quic... [mani: CCed stable list] Signed-off-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/bus/mhi/core/pm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c index 044dcdd723a7..7d69b740b9f9 100644 --- a/drivers/bus/mhi/core/pm.c +++ b/drivers/bus/mhi/core/pm.c @@ -298,7 +298,8 @@ int mhi_pm_m0_transition(struct mhi_controller *mhi_cntrl) read_lock_irq(&mhi_chan->lock);
/* Only ring DB if ring is not empty */ - if (tre_ring->base && tre_ring->wp != tre_ring->rp) + if (tre_ring->base && tre_ring->wp != tre_ring->rp && + mhi_chan->ch_state == MHI_CH_STATE_ENABLED) mhi_ring_chan_db(mhi_cntrl, mhi_chan); read_unlock_irq(&mhi_chan->lock); }