6.6-stable review patch. If anyone has any objections, please let me know.
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From: Murali Nalajala quic_mnalajal@quicinc.com
commit 9960085a3a82c58d3323c1c20b991db6045063b0 upstream.
Currently get_wq_ctx() is wrongly configured as a standard call. When two SMC calls are in sleep and one SMC wakes up, it calls get_wq_ctx() to resume the corresponding sleeping thread. But if get_wq_ctx() is interrupted, goes to sleep and another SMC call is waiting to be allocated a waitq context, it leads to a deadlock.
To avoid this get_wq_ctx() must be an atomic call and can't be a standard SMC call. Hence mark get_wq_ctx() as a fast call.
Fixes: 6bf325992236 ("firmware: qcom: scm: Add wait-queue handling logic") Cc: stable@vger.kernel.org Signed-off-by: Murali Nalajala quic_mnalajal@quicinc.com Signed-off-by: Unnathi Chalicheemala quic_uchalich@quicinc.com Reviewed-by: Elliot Berman quic_eberman@quicinc.com Link: https://lore.kernel.org/r/20240814223244.40081-1-quic_uchalich@quicinc.com Signed-off-by: Bjorn Andersson andersson@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/firmware/qcom_scm-smc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/firmware/qcom_scm-smc.c +++ b/drivers/firmware/qcom_scm-smc.c @@ -71,7 +71,7 @@ int scm_get_wq_ctx(u32 *wq_ctx, u32 *fla struct arm_smccc_res get_wq_res; struct arm_smccc_args get_wq_ctx = {0};
- get_wq_ctx.args[0] = ARM_SMCCC_CALL_VAL(ARM_SMCCC_STD_CALL, + get_wq_ctx.args[0] = ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64, ARM_SMCCC_OWNER_SIP, SCM_SMC_FNID(QCOM_SCM_SVC_WAITQ, QCOM_SCM_WAITQ_GET_WQ_CTX));