bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 87 insertions, 0 deletions

diff --git a/tools/perf/Documentation/perf-test.txt b/tools/perf/Documentation/perf-test.txt
new file mode 100644
index 000000000..81c8525f5
--- /dev/null
+++ b/tools/perf/Documentation/perf-test.txt
@@ -0,0 +1,87 @@
+perf-test(1)
+============
+
+NAME
+----
+perf-test - Runs sanity tests.
+
+SYNOPSIS
+--------
+[verse]
+'perf test [<options>] [{list <test-name-fragment>|[<test-name-fragments>|<test-numbers>]}]'
+
+DESCRIPTION
+-----------
+This command does assorted sanity tests, initially through linked routines but
+also will look for a directory with more tests in the form of scripts.
+
+To get a list of available tests use 'perf test list', specifying a test name
+fragment will show all tests that have it.
+
+To run just specific tests, inform test name fragments or the numbers obtained
+from 'perf test list'.
+
+OPTIONS
+-------
+-s::
+--skip::
+	Tests to skip (comma separated numeric list).
+
+-v::
+-vv::
+-vvv::
+--verbose::
+	With a single '-v', verbose level 1, only failing test output
+	is displayed. With '-vv' and higher all test output is shown.
+
+-S::
+--sequential::
+	Run all tests one after the other. By default "exclusive"
+	tests are run sequentially, but other tests are run in
+	parallel to speed execution.
+
+-r::
+--runs-per-test::
+	Run each test the given number of times, by default once. This
+	option can be useful to determine if a test is flaky.
+
+-F::
+--dont-fork::
+	Do not fork child for each test, run all tests within single process, this
+	sets sequential mode.
+
+--dso::
+	Specify a DSO for the "Symbols" test.
+
+-w::
+--workload=::
+	Run a built-in workload, to list them use '--list-workloads', current
+	ones include: noploop, thloop, leafloop, sqrtloop, brstack, datasym,
+	context_switch_loop, deterministic, named_threads and landlock.
+
+	Used with the shell script regression tests.
+
+	Some accept an extra parameter:
+
+		seconds: leafloop, noploop, sqrtloop, thloop
+		nrloops: brstack, context_switch_loop
+
+	'named_threads' accepts the number of threads and the number of loops to
+	do in each thread.
+
+	The datasym, landlock and deterministic workloads don't accept any.
+
+--list-workloads::
+	List the available workloads to use with -w/--workload.
+
+--record-ctl=fifo:ctl-fifo[,ack-fifo]::
+	This option is used to communicate with a perf record session in order
+	to control the recording scope to only the workload and avoid recording
+	setup and teardown code. When specifying this option, the same FIFO path
+	must be specified in the record session via:
+
+	  perf record -D -1 --control=fifo:ctl-fifo[,ack-fifo] ...
+
+	Perf test sends 'enable' and 'disable' commands through ctl-fifo to
+	control event recording. If 'ack-fifo' is provided, the workload runner
+	waits for an 'ack' response after each command.