The kernel would like to have all stack VLA usage removed[1]. The array here is fixed (declared with a const variable) but it appears like a VLA to the compiler. Also, currently we are putting 768 bytes on the stack. This function is only called on the error path so performance is not critical, let's just allocate the memory instead of using the stack. This saves stack space and removes the VLA build warning. kmalloc a buffer for dumping state instead of using the stack. [1]: https://lkml.org/lkml/2018/3/7/621 CC: Kees Cook <keescook@xxxxxxxxxx> Signed-off-by: Tobin C. Harding <me@xxxxxxxx> Signed-off-by: Stefan Wahren <stefan.wahren@xxxxxxxx> --- .../vc04_services/interface/vchiq_arm/vchiq_arm.c | 25 ++++++++++++++-------- 1 file changed, 16 insertions(+), 9 deletions(-) diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c index 8575bd8..d46a5b8 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c @@ -3415,13 +3415,18 @@ vchiq_release_service(VCHIQ_SERVICE_HANDLE_T handle) return ret; } +struct service_data_struct { + int fourcc; + int clientid; + int use_count; +}; + void vchiq_dump_service_use_state(VCHIQ_STATE_T *state) { VCHIQ_ARM_STATE_T *arm_state = vchiq_platform_get_arm_state(state); + struct service_data_struct *service_data; int i, j = 0; - /* Only dump 64 services */ - static const int local_max_services = 64; /* If there's more than 64 services, only dump ones with * non-zero counts */ int only_nonzero = 0; @@ -3432,25 +3437,25 @@ vchiq_dump_service_use_state(VCHIQ_STATE_T *state) int peer_count; int vc_use_count; int active_services; - struct service_data_struct { - int fourcc; - int clientid; - int use_count; - } service_data[local_max_services]; if (!arm_state) return; + service_data = kmalloc_array(MAX_SERVICES, sizeof(*service_data), + GFP_KERNEL); + if (!service_data) + return; + read_lock_bh(&arm_state->susp_res_lock); vc_suspend_state = arm_state->vc_suspend_state; vc_resume_state = arm_state->vc_resume_state; peer_count = arm_state->peer_use_count; vc_use_count = arm_state->videocore_use_count; active_services = state->unused_service; - if (active_services > local_max_services) + if (active_services > MAX_SERVICES) only_nonzero = 1; - for (i = 0; (i < active_services) && (j < local_max_services); i++) { + for (i = 0; (i < active_services) && (j < MAX_SERVICES); i++) { VCHIQ_SERVICE_T *service_ptr = state->services[i]; if (!service_ptr) @@ -3494,6 +3499,8 @@ vchiq_dump_service_use_state(VCHIQ_STATE_T *state) vchiq_log_warning(vchiq_susp_log_level, "--- Overall vchiq instance use count %d", vc_use_count); + kfree(service_data); + vchiq_dump_platform_use_state(state); } -- 2.7.4 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
