systemtap: fix vsprintf errors

In some configurations (such as 32-bit arm), using printf() causes
gcc errors.  Backport a patch from upstream to fix this.

(From OE-Core rev: 6340a6477ddf0fee6c18cf99262704a715491f60)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 46 insertions, 0 deletions

diff --git a/meta/recipes-kernel/systemtap/systemtap/0001-PR28778-gcc-warning-tweak-for-sprintf-precision-para.patch b/meta/recipes-kernel/systemtap/systemtap/0001-PR28778-gcc-warning-tweak-for-sprintf-precision-para.patch
new file mode 100644
index 0000000000..0801cb57ec
--- /dev/null
+++ b/meta/recipes-kernel/systemtap/systemtap/0001-PR28778-gcc-warning-tweak-for-sprintf-precision-para.patch
@@ -0,0 +1,45 @@
+Upstream-Status: Backport
+Signed-off-by: Ross Burton <ross.burton@arm.com>
+
+From b0422e9e5a539164af75cddcaeb01bceca56bf12 Mon Sep 17 00:00:00 2001
+From: "Frank Ch. Eigler" <fche@redhat.com>
+Date: Thu, 13 Jan 2022 18:33:15 -0500
+Subject: [PATCH] PR28778: gcc warning tweak for sprintf precision parameter
+
+A precision=-1 sentinel value got interpreted as UINT_MAX in a
+context, leading to diagnostics like:
+
+/usr/share/systemtap/runtime/vsprintf.c:341:23: error: 'strnlen' specified bound 4294967295 may exceed maximum object size 2147483647 [-Werror=stringop-overread]
+
+Adding a clamp_t() around the parameter field to keep it limited to
+STP_BUFFER_SIZE (8K by default), which is apprx. the limit for a
+single printf.
+---
+ runtime/vsprintf.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/runtime/vsprintf.c b/runtime/vsprintf.c
+index cd31a938b..606f685e8 100644
+--- a/runtime/vsprintf.c
++++ b/runtime/vsprintf.c
+@@ -338,7 +338,7 @@ _stp_vsprint_memory(char * str, char * end, const char * ptr,
+        if (format == 's') {
+                if ((unsigned long)ptr < PAGE_SIZE)
+                        ptr = "<NULL>";
+-               len = strnlen(ptr, precision);
++               len = strnlen(ptr, clamp_t(size_t, precision, 0, STP_BUFFER_SIZE));                
+        }
+        else if (precision > 0)
+                len = precision;
+@@ -410,7 +410,7 @@ _stp_vsprint_memory_size(const char * ptr, int width, int precision,
+        if (format == 's') {
+                if ((unsigned long)ptr < PAGE_SIZE)
+                        ptr = "<NULL>";
+-               len = strnlen(ptr, precision);
++               len = strnlen(ptr, clamp_t(size_t, precision, 0, STP_BUFFER_SIZE));
+        }
+        else if (precision > 0)
+                len = precision;
+-- 
+2.25.1
+
diff --git a/meta/recipes-kernel/systemtap/systemtap_git.inc b/meta/recipes-kernel/systemtap/systemtap_git.inc
index 22b07f1516..36c934c2fa 100644
--- a/meta/recipes-kernel/systemtap/systemtap_git.inc
+++ b/meta/recipes-kernel/systemtap/systemtap_git.inc
@@ -7,6 +7,7 @@ SRC_URI = "git://sourceware.org/git/systemtap.git;branch=master \
            file://0001-Do-not-let-configure-write-a-python-location-into-th.patch \
            file://0001-Install-python-modules-to-correct-library-dir.patch \
            file://0001-staprun-stapbpf-don-t-support-installing-a-non-root.patch \
+           file://0001-PR28778-gcc-warning-tweak-for-sprintf-precision-para.patch \
            "
 
 COMPATIBLE_HOST = '(x86_64|i.86|powerpc|arm|aarch64|microblazeel|mips).*-linux'