Merge branch 'bpf-add-bpf_stream_print_stack-kfunc'

Emil Tsalapatis says:

====================
bpf: Add bpf_stream_print_stack kfunc

Add a new bpf_stream_print_stack kfunc for printing a BPF program stack
into a BPF stream. Update the verifier to allow the new kfunc to be
called with BPF spinlocks held, along with bpf_stream_vprintk.

Patchset spun out of the larger libarena + ASAN patchset.
(https://lore.kernel.org/bpf/20260127181610.86376-1-emil@etsalapatis.com/)

Changeset:
	- Update bpf_stream_print_stack to take stream_id arg (Kumar)
	- Added selftest for the bpf_stream_print_stack
	- Add selftest for calling the streams kfuncs under lock

v2->v1: (https://lore.kernel.org/bpf/20260202193311.446717-1-emil@etsalapatis.com/)
	- Updated Signed-off-by to be consistent with past submissions
	- Updated From email to be consistent with Signed-off-by

Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
====================

Link: https://patch.msgid.link/20260203180424.14057-1-emil@etsalapatis.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/stream.c b/tools/testing/selftests/bpf/progs/stream.c
index 4a5bd852f10c..6f999ba951a3 100644
--- a/tools/testing/selftests/bpf/progs/stream.c
+++ b/tools/testing/selftests/bpf/progs/stream.c
@@ -42,6 +42,10 @@ int size;
 u64 fault_addr;
 void *arena_ptr;
 
+#define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8)))
+
+private(STREAM) struct bpf_spin_lock block;
+
 SEC("syscall")
 __success __retval(0)
 int stream_exhaust(void *ctx)
@@ -234,4 +238,53 @@ int stream_arena_callback_fault(void *ctx)
 	return 0;
 }
 
+SEC("syscall")
+__arch_x86_64
+__arch_arm64
+__success __retval(0)
+__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
+__stderr("Call trace:\n"
+"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
+"|[ \t]+[^\n]+\n)*}}")
+int stream_print_stack_kfunc(void *ctx)
+{
+	return bpf_stream_print_stack(BPF_STDERR);
+}
+
+SEC("syscall")
+__success __retval(-2)
+int stream_print_stack_invalid_id(void *ctx)
+{
+	/* Try to pass an invalid stream ID. */
+	return bpf_stream_print_stack((enum bpf_stream_id)0xbadcafe);
+}
+
+SEC("syscall")
+__arch_x86_64
+__arch_arm64
+__success __retval(0)
+__stdout(_STR)
+__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
+__stderr("Call trace:\n"
+"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
+"|[ \t]+[^\n]+\n)*}}")
+int stream_print_kfuncs_locked(void *ctx)
+{
+	int ret;
+
+	bpf_spin_lock(&block);
+
+	ret = bpf_stream_printk(BPF_STDOUT, _STR);
+	if (ret)
+		goto out;
+
+	ret = bpf_stream_print_stack(BPF_STDERR);
+
+out:
+	bpf_spin_unlock(&block);
+
+	return ret;
+}
+
+
 char _license[] SEC("license") = "GPL";