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authorQiang Yu <quic_qianyu@quicinc.com>2022-10-16 06:05:32 +0300
committerManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>2022-10-28 20:29:10 +0300
commit869a99907faea6d1835b0bd0d0422ae3519c6ea9 (patch)
tree3089c84a1d8241f64a871ac79fc40fb139127312 /drivers/bus
parent46db0ba12be6cfd043df1d09b5831cb84ce2307f (diff)
downloadlinux-869a99907faea6d1835b0bd0d0422ae3519c6ea9.tar.xz
bus: mhi: host: Fix race between channel preparation and M0 event
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@quicinc.com [mani: CCed stable list] Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Diffstat (limited to 'drivers/bus')
-rw-r--r--drivers/bus/mhi/host/pm.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
index 4a42186ff111..083459028a4b 100644
--- a/drivers/bus/mhi/host/pm.c
+++ b/drivers/bus/mhi/host/pm.c
@@ -301,7 +301,8 @@ 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);
}