From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- drivers/gpu/trace/Kconfig | 13 +++++++++++++ drivers/gpu/trace/Makefile | 3 +++ drivers/gpu/trace/trace_gpu_mem.c | 13 +++++++++++++ 3 files changed, 29 insertions(+) create mode 100644 drivers/gpu/trace/Kconfig create mode 100644 drivers/gpu/trace/Makefile create mode 100644 drivers/gpu/trace/trace_gpu_mem.c (limited to 'drivers/gpu/trace') diff --git a/drivers/gpu/trace/Kconfig b/drivers/gpu/trace/Kconfig new file mode 100644 index 000000000..cd3d19c4a --- /dev/null +++ b/drivers/gpu/trace/Kconfig @@ -0,0 +1,13 @@ +# SPDX-License-Identifier: GPL-2.0-only + +config TRACE_GPU_MEM + bool "Enable GPU memory usage tracepoints" + default n + help + Choose this option to enable tracepoints for tracking + global and per-process GPU memory usage. Intended for + performance profiling and required for Android. + + Tracepoint availability varies by GPU driver. + + If in doubt, say "N". diff --git a/drivers/gpu/trace/Makefile b/drivers/gpu/trace/Makefile new file mode 100644 index 000000000..b70fbdc58 --- /dev/null +++ b/drivers/gpu/trace/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0 + +obj-$(CONFIG_TRACE_GPU_MEM) += trace_gpu_mem.o diff --git a/drivers/gpu/trace/trace_gpu_mem.c b/drivers/gpu/trace/trace_gpu_mem.c new file mode 100644 index 000000000..01e855897 --- /dev/null +++ b/drivers/gpu/trace/trace_gpu_mem.c @@ -0,0 +1,13 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * GPU memory trace points + * + * Copyright (C) 2020 Google, Inc. + */ + +#include + +#define CREATE_TRACE_POINTS +#include + +EXPORT_TRACEPOINT_SYMBOL(gpu_mem_total); -- cgit v1.3.1