From ec369eac0795cfa8f4d3a0cd35a1e8e15f780331 Mon Sep 17 00:00:00 2001 From: Srinivas Kandagatla Date: Tue, 16 Jun 2026 18:02:57 +0100 Subject: [PATCH] ASoC: qcom: q6apm: fix NULL pointer dereference in graph_callback commit 2e9261761b35f0b67b7487688cd1365f535be0b3 upstream. When q6apm_free_fragments() is called it frees rx_data.buf/tx_data.buf and sets them to NULL under graph->lock. A late DSP buffer-done response can race with this: graph_callback() passes the !graph->ar_graph guard (not yet NULL), acquires the lock, but then dereferences a now-NULL buf pointer to read buf[token].phys, crashing at virtual address 0x10. Add a NULL check for buf inside the mutex-protected section in both the write-done (DATA_CMD_RSP_WR_SH_MEM_EP_DATA_BUFFER_DONE_V2) and read-done (DATA_CMD_RSP_RD_SH_MEM_EP_DATA_BUFFER_V2) handlers and bail out cleanly if buffers have already been freed. This problem is only shown up recently while apr bus was updated to process the commands per service rather from single global queue. Fixes: 5477518b8a0e ("ASoC: qdsp6: audioreach: add q6apm support") Cc: Stable@vger.kernel.org Assisted-by: Claude:claude-4-6-sonnet Reported-by: Val Packett Closes: https://lore.kernel.org/all/133ced18-1aa9-475d-80d8-6120678bdde4@packett.cool/ Signed-off-by: Srinivas Kandagatla Link: https://patch.msgid.link/20260616170257.9381-1-srinivas.kandagatla@oss.qualcomm.com Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- sound/soc/qcom/qdsp6/q6apm.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/sound/soc/qcom/qdsp6/q6apm.c b/sound/soc/qcom/qdsp6/q6apm.c index 7b447cb50d50..e2ad6dc2dc85 100644 --- a/sound/soc/qcom/qdsp6/q6apm.c +++ b/sound/soc/qcom/qdsp6/q6apm.c @@ -533,6 +533,10 @@ static int graph_callback(struct gpr_resp_pkt *data, void *priv, int op) token = hdr->token & APM_WRITE_TOKEN_MASK; done = data->payload; + if (!graph->rx_data.buf) { + mutex_unlock(&graph->lock); + break; + } phys = graph->rx_data.buf[token].phys; mutex_unlock(&graph->lock); /* token numbering starts at 0 */ @@ -567,6 +571,10 @@ static int graph_callback(struct gpr_resp_pkt *data, void *priv, int op) client_event = APM_CLIENT_EVENT_DATA_READ_DONE; mutex_lock(&graph->lock); rd_done = data->payload; + if (!graph->tx_data.buf) { + mutex_unlock(&graph->lock); + break; + } phys = graph->tx_data.buf[hdr->token].phys; mutex_unlock(&graph->lock); /* token numbering starts at 0 */