samples/bpf: use kprobe and urandom_read_iter

14c174633f34 ("random: remove unused tracepoints") removed all the
tracepoints from drivers/char/random.c, one of which,
random:urandom_read.

1b388e7765f2 ("random: convert to using fops->read_iter()") replaced
kernel function urandom_read with urandom_read_iter.
Therefore, kprobe on urandom_read is not working any more:

Fix breakage by replacing tracepoint with kprobing and replacing
urandom_read with urandom_read_iter.

TEST PLAN:
PASS: build-pkgs -c -p linux
PASS: build-pkgs -c -p linux-rt
PASS: make -j 16 M=samples/bpf
PASS: sudo samples/bpf/test_overhead

Closes-Bug: 1999136

Change-Id: Idac88160050abaa7ebe7098a54792650f2d691cd
Signed-off-by: Wentao Zhang <wentao.zhang@windriver.com>

kernel-rt/debian/patches/0039-samples-bpf-use-kprobe-and-urandom_read_iter.patch

@@ -0,0 +1,67 @@
+From 3e65002714f5b4d20ab30b01a58ddb0e243a74ac Mon Sep 17 00:00:00 2001
+From: Wentao Zhang <wentao.zhang@windriver.com>
+Date: Thu, 8 Dec 2022 11:55:17 +0800
+Subject: [PATCH] samples/bpf: use kprobe and urandom_read_iter
+
+14c174633f34 ("random: remove unused tracepoints") removed all the
+tracepoints from drivers/char/random.c, one of which,
+random:urandom_read.
+
+1b388e7765f2 ("random: convert to using fops->read_iter()") replaced
+kernel function urandom_read with urandom_read_iter.
+Therefore, kprobe on urandom_read is not working any more.
+
+Use kprobing to replace the tracepoint and use urandom_read_iter
+to replace urandom_read to fix the breakage.
+
+Fixes: 1b388e7765f2 ("random: convert to using fops->read_iter()")
+Fixes: 14c174633f34 ("random: remove unused tracepoints")
+Signed-off-by: Wentao Zhang <wentao.zhang@windriver.com>
+---
+ samples/bpf/test_overhead_kprobe_kern.c | 2 +-
+ samples/bpf/test_overhead_raw_tp_kern.c | 2 +-
+ samples/bpf/test_overhead_tp_kern.c     | 2 +-
+ 3 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/samples/bpf/test_overhead_kprobe_kern.c b/samples/bpf/test_overhead_kprobe_kern.c
+index f6d593e47..2dcb4ba0e 100644
+--- a/samples/bpf/test_overhead_kprobe_kern.c
++++ b/samples/bpf/test_overhead_kprobe_kern.c
+@@ -38,7 +38,7 @@ int prog(struct pt_regs *ctx)
+ 	return 0;
+ }
+ 
+-SEC("kprobe/urandom_read")
++SEC("kprobe/urandom_read_iter")
+ int prog2(struct pt_regs *ctx)
+ {
+ 	return 0;
+diff --git a/samples/bpf/test_overhead_raw_tp_kern.c b/samples/bpf/test_overhead_raw_tp_kern.c
+index 8763181a3..34a5aba61 100644
+--- a/samples/bpf/test_overhead_raw_tp_kern.c
++++ b/samples/bpf/test_overhead_raw_tp_kern.c
+@@ -9,7 +9,7 @@ int prog(struct bpf_raw_tracepoint_args *ctx)
+ 	return 0;
+ }
+ 
+-SEC("raw_tracepoint/urandom_read")
++SEC("kprobe/urandom_read_iter")
+ int prog2(struct bpf_raw_tracepoint_args *ctx)
+ {
+ 	return 0;
+diff --git a/samples/bpf/test_overhead_tp_kern.c b/samples/bpf/test_overhead_tp_kern.c
+index eaa32693f..d5f7abb4c 100644
+--- a/samples/bpf/test_overhead_tp_kern.c
++++ b/samples/bpf/test_overhead_tp_kern.c
+@@ -28,7 +28,7 @@ struct urandom_read {
+ 	int pool_left;
+ 	int input_left;
+ };
+-SEC("tracepoint/random/urandom_read")
++SEC("kprobe/urandom_read_iter")
+ int prog2(struct urandom_read *ctx)
+ {
+ 	return 0;
+-- 
+2.25.1
+

kernel-rt/debian/patches/series

@@ -34,3 +34,4 @@
 0036-xfs-open-code-ioend-needs-workqueue-helper.patch
 0037-xfs-drop-unused-ioend-private-merge-and-setfilesize-.patch
 0038-xfs-drop-unnecessary-setfilesize-helper.patch
+0039-samples-bpf-use-kprobe-and-urandom_read_iter.patch

kernel-std/debian/patches/0038-samples-bpf-use-kprobe-and-urandom_read_iter.patch

@@ -0,0 +1,67 @@
+From 3e65002714f5b4d20ab30b01a58ddb0e243a74ac Mon Sep 17 00:00:00 2001
+From: Wentao Zhang <wentao.zhang@windriver.com>
+Date: Thu, 8 Dec 2022 11:55:17 +0800
+Subject: [PATCH] samples/bpf: use kprobe and urandom_read_iter
+
+14c174633f34 ("random: remove unused tracepoints") removed all the
+tracepoints from drivers/char/random.c, one of which,
+random:urandom_read.
+
+1b388e7765f2 ("random: convert to using fops->read_iter()") replaced
+kernel function urandom_read with urandom_read_iter.
+Therefore, kprobe on urandom_read is not working any more.
+
+Use kprobing to replace the tracepoint and use urandom_read_iter
+to replace urandom_read to fix the breakage.
+
+Fixes: 1b388e7765f2 ("random: convert to using fops->read_iter()")
+Fixes: 14c174633f34 ("random: remove unused tracepoints")
+Signed-off-by: Wentao Zhang <wentao.zhang@windriver.com>
+---
+ samples/bpf/test_overhead_kprobe_kern.c | 2 +-
+ samples/bpf/test_overhead_raw_tp_kern.c | 2 +-
+ samples/bpf/test_overhead_tp_kern.c     | 2 +-
+ 3 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/samples/bpf/test_overhead_kprobe_kern.c b/samples/bpf/test_overhead_kprobe_kern.c
+index f6d593e47..2dcb4ba0e 100644
+--- a/samples/bpf/test_overhead_kprobe_kern.c
++++ b/samples/bpf/test_overhead_kprobe_kern.c
+@@ -38,7 +38,7 @@ int prog(struct pt_regs *ctx)
+ 	return 0;
+ }
+ 
+-SEC("kprobe/urandom_read")
++SEC("kprobe/urandom_read_iter")
+ int prog2(struct pt_regs *ctx)
+ {
+ 	return 0;
+diff --git a/samples/bpf/test_overhead_raw_tp_kern.c b/samples/bpf/test_overhead_raw_tp_kern.c
+index 8763181a3..34a5aba61 100644
+--- a/samples/bpf/test_overhead_raw_tp_kern.c
++++ b/samples/bpf/test_overhead_raw_tp_kern.c
+@@ -9,7 +9,7 @@ int prog(struct bpf_raw_tracepoint_args *ctx)
+ 	return 0;
+ }
+ 
+-SEC("raw_tracepoint/urandom_read")
++SEC("kprobe/urandom_read_iter")
+ int prog2(struct bpf_raw_tracepoint_args *ctx)
+ {
+ 	return 0;
+diff --git a/samples/bpf/test_overhead_tp_kern.c b/samples/bpf/test_overhead_tp_kern.c
+index eaa32693f..d5f7abb4c 100644
+--- a/samples/bpf/test_overhead_tp_kern.c
++++ b/samples/bpf/test_overhead_tp_kern.c
+@@ -28,7 +28,7 @@ struct urandom_read {
+ 	int pool_left;
+ 	int input_left;
+ };
+-SEC("tracepoint/random/urandom_read")
++SEC("kprobe/urandom_read_iter")
+ int prog2(struct urandom_read *ctx)
+ {
+ 	return 0;
+-- 
+2.25.1
+

kernel-std/debian/patches/series

@@ -33,3 +33,4 @@
 0035-xfs-open-code-ioend-needs-workqueue-helper.patch
 0036-xfs-drop-unused-ioend-private-merge-and-setfilesize-.patch
 0037-xfs-drop-unnecessary-setfilesize-helper.patch
+0038-samples-bpf-use-kprobe-and-urandom_read_iter.patch