6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Murali Nalajala <quic_mnalajal@xxxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Signed-off-by: Murali Nalajala <quic_mnalajal@xxxxxxxxxxx>
Signed-off-by: Unnathi Chalicheemala <quic_uchalich@xxxxxxxxxxx>
Reviewed-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240814223244.40081-1-quic_uchalich@xxxxxxxxxxx
Signed-off-by: Bjorn Andersson <andersson@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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));
