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From f205565c00e0f98575316526fee320307ab0460e Mon Sep 17 00:00:00 2001 |
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From: Sasha Levin <sashal@kernel.org> |
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Date: Sun, 16 Oct 2022 11:05:32 +0800 |
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Subject: bus: mhi: host: Fix race between channel preparation and M0 event |
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From: Qiang Yu <quic_qianyu@quicinc.com> |
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[ Upstream commit 869a99907faea6d1835b0bd0d0422ae3519c6ea9 ] |
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There is a race condition where mhi_prepare_channel() updates the |
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read and write pointers as the base address and in parallel, if |
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an M0 transition occurs, the tasklet goes ahead and rings |
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doorbells for all channels with a delta in TRE rings assuming |
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they are already enabled. This causes a null pointer access. Fix |
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it by adding a channel enabled check before ringing channel |
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doorbells. |
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|
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Cc: stable@vger.kernel.org # 5.19 |
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Fixes: a6e2e3522f29 "bus: mhi: core: Add support for PM state transitions" |
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Signed-off-by: Qiang Yu <quic_qianyu@quicinc.com> |
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Reviewed-by: Manivannan Sadhasivam <mani@kernel.org> |
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Link: https://lore.kernel.org/r/1665889532-13634-1-git-send-email-quic_qianyu@quicinc.com |
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[mani: CCed stable list] |
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Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> |
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Signed-off-by: Sasha Levin <sashal@kernel.org> |
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--- |
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drivers/bus/mhi/core/pm.c | 3 ++- |
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1 file changed, 2 insertions(+), 1 deletion(-) |
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diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c |
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index 1020268a075a..1a87b9c6c2f8 100644 |
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--- a/drivers/bus/mhi/core/pm.c |
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+++ b/drivers/bus/mhi/core/pm.c |
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@@ -297,7 +297,8 @@ int mhi_pm_m0_transition(struct mhi_controller *mhi_cntrl) |
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read_lock_irq(&mhi_chan->lock); |
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/* Only ring DB if ring is not empty */ |
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- if (tre_ring->base && tre_ring->wp != tre_ring->rp) |
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+ if (tre_ring->base && tre_ring->wp != tre_ring->rp && |
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+ mhi_chan->ch_state == MHI_CH_STATE_ENABLED) |
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mhi_ring_chan_db(mhi_cntrl, mhi_chan); |
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read_unlock_irq(&mhi_chan->lock); |
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} |
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-- |
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2.35.1 |
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