From 06a4f816a70ad76e967e1ecd7ed64cac2bb10f1d Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Thu, 29 Jul 2021 12:52:14 +0200 Subject: [PATCH 142/166] arm64/sve: Delay freeing memory in fpsimd_flush_thread() fpsimd_flush_thread() invokes kfree() via sve_free() within a preempt disabled section which is not working on -RT. Delay freeing of memory until preemption is enabled again. Signed-off-by: Sebastian Andrzej Siewior --- arch/arm64/kernel/fpsimd.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) Index: linux-5.15.32-rt39/arch/arm64/kernel/fpsimd.c =================================================================== --- linux-5.15.32-rt39.orig/arch/arm64/kernel/fpsimd.c +++ linux-5.15.32-rt39/arch/arm64/kernel/fpsimd.c @@ -1033,6 +1033,7 @@ void fpsimd_thread_switch(struct task_st void fpsimd_flush_thread(void) { int vl, supported_vl; + void *sve_state = NULL; if (!system_supports_fpsimd()) return; @@ -1045,7 +1046,10 @@ void fpsimd_flush_thread(void) if (system_supports_sve()) { clear_thread_flag(TIF_SVE); - sve_free(current); + + /* Defer kfree() while in atomic context */ + sve_state = current->thread.sve_state; + current->thread.sve_state = NULL; /* * Reset the task vector length as required. @@ -1079,6 +1083,7 @@ void fpsimd_flush_thread(void) } put_cpu_fpsimd_context(); + kfree(sve_state); } /*