mctp-i2c rx implementation doesn't call
__i2c_transfer which calls the i2c reply trace function.

Add an mctp_reply trace function that will be used instead.

Signed-off-by: Tal Yacobi <talycb8@gmail.com>
---
 drivers/net/mctp/mctp-i2c.c |  3 +++
 include/trace/events/mctp.h | 16 ++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/net/mctp/mctp-i2c.c b/drivers/net/mctp/mctp-i2c.c
index b37a9e4bade4..22754f4e4a8d 100644
--- a/drivers/net/mctp/mctp-i2c.c
+++ b/drivers/net/mctp/mctp-i2c.c
@@ -24,6 +24,7 @@
 #include <linux/if_arp.h>
 #include <net/mctp.h>
 #include <net/mctpdevice.h>
+#include <trace/events/mctp.h>
 
 /* byte_count is limited to u8 */
 #define MCTP_I2C_MAXBLOCK 255
@@ -312,6 +313,8 @@ static int mctp_i2c_recv(struct mctp_i2c_dev *midev)
 		return -ENOMEM;
 	}
 
+	trace_mctp_reply(midev->rx_buffer, recvlen);
+
 	skb->protocol = htons(ETH_P_MCTP);
 	skb_put_data(skb, midev->rx_buffer, recvlen);
 	skb_reset_mac_header(skb);
diff --git a/include/trace/events/mctp.h b/include/trace/events/mctp.h
index 165cf25f77a7..d115c353dff9 100644
--- a/include/trace/events/mctp.h
+++ b/include/trace/events/mctp.h
@@ -73,6 +73,22 @@ TRACE_EVENT(mctp_key_release,
 	)
 );
 
+TRACE_EVENT(mctp_reply,
+	TP_PROTO(const u8 *rx_buffer, const size_t recvlen),
+	TP_ARGS(rx_buffer, recvlen),
+	TP_STRUCT__entry(
+		__field(__u16, len)
+		__dynamic_array(__u8, buf, recvlen)),
+	TP_fast_assign(
+		__entry->len = (__u16) recvlen;
+		memcpy(__get_dynamic_array(buf), rx_buffer, recvlen);
+	),
+	TP_printk("l=%u [%*phD]",
+		__entry->len,
+		__entry->len, __get_dynamic_array(buf)
+	)
+);
+
 #endif
 
 #include <trace/define_trace.h>
-- 
2.43.0

Hi Tal,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on horms-ipvs/master v6.10-rc1 next-20240531]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Tal-Yacobi/mctp-i2c-Add-rx-trace/20240528-223555
base:   linus/master
patch link:    https://lore.kernel.org/r/20240528143420.742611-1-talycb8%40gmail.com
patch subject: [PATCH] mctp i2c: Add rx trace
config: hexagon-randconfig-r052-20240531 (https://download.01.org/0day-ci/archive/20240601/202406010530.SKASSBs4-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project bafda89a0944d947fc4b3b5663185e07a397ac30)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240601/202406010530.SKASSBs4-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202406010530.SKASSBs4-lkp@intel.com/

All errors (new ones prefixed by >>, old ones prefixed by <<):

WARNING: modpost: missing MODULE_DESCRIPTION() in vmlinux.o
WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/locking/locktorture.o
WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/rcu/rcutorture.o
WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/rcu/rcuscale.o
WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/rcu/refscale.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_cp855.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_cp857.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_cp863.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_cp864.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_cp865.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_cp869.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_cp936.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_ascii.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_iso8859-5.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_iso8859-7.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_iso8859-9.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/nls_iso8859-15.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/mac-celtic.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/mac-inuit.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nls/mac-romanian.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/jbd2/jbd2.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/fat/fat.o
WARNING: modpost: missing MODULE_DESCRIPTION() in crypto/xor.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/math/rational.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/crypto/libarc4.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/zlib_inflate/zlib_inflate.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/zlib_deflate/zlib_deflate.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/video/backlight/rt4831-backlight.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/video/fbdev/vfb.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/regulator/rt4831-regulator.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/reset/hisilicon/hi6220_reset.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/tty/goldfish.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/char/lp.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/char/ppdev.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpu/drm/gud/gud.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpu/drm/drm_panel_orientation_quirks.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpu/drm/udl/udl.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/base/regmap/regmap-spmi.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/base/regmap/regmap-w1.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/mfd/pcf50633-gpio.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/mfd/rt4831.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/dax/dax.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/host/ohci-exynos.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/host/xhci-pci-renesas.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/serial/usb_debug.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/serial/navman.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/input/matrix-keymap.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/i2c/busses/i2c-qup.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/media/rc/rc-core.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-ezkey.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-gyration.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-holtek-kbd.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-holtek-mouse.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-ite.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-kensington.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-lcpower.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-lenovo.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-letsketch.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-maltron.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-mf.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-megaworld.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-ntrig.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-pl.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-redragon.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-retrode.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-semitek.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-speedlink.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-topseed.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-uclogic.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/staging/greybus/gb-log.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/staging/greybus/gb-loopback.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/staging/greybus/gb-raw.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/staging/greybus/gb-vibrator.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/staging/greybus/gb-gbphy.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/staging/greybus/gb-gpio.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/staging/greybus/gb-i2c.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/staging/greybus/gb-pwm.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/staging/greybus/gb-uart.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/staging/greybus/gb-usb.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/rpmsg/rpmsg_char.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hwtracing/intel_th/intel_th_msu_sink.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/parport/parport.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/spmi/hisi-spmi-controller.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/spmi/spmi-pmic-arb.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/greybus/greybus.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/greybus/gb-es2.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/siox/siox-bus-gpio.o
>> ERROR: modpost: "__tracepoint_mctp_reply" [drivers/net/mctp/mctp-i2c.ko] undefined!
>> ERROR: modpost: "__traceiter_mctp_reply" [drivers/net/mctp/mctp-i2c.ko] undefined!

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Hi Tal,

Thanks for the contribution! Some comments:

> mctp-i2c rx implementation doesn't call
> __i2c_transfer which calls the i2c reply trace function.

No, but we can trace the i2c rx path through the trace_i2c_slave
tracepoint. It is a little messier than tracing trace_i2c_write, but
has been sufficient with the debugging I've needed in the past.

> Add an mctp_reply trace function that will be used instead.

Can you elaborate a little on what you were/are looking to inspect
here? (mainly: which packet fields are you interested in?) That will
help to determine the best approach here.

Cheers,


Jeremy

Hi Jeremy,

Thanks for the reply.

> > mctp-i2c rx implementation doesn't call
> > __i2c_transfer which calls the i2c reply trace function.
>
> No, but we can trace the i2c rx path through the trace_i2c_slave
> tracepoint. It is a little messier than tracing trace_i2c_write, but
> has been sufficient with the debugging I've needed in the past.

Oh, I missed that.
I had to test it with an older kernel without i2c_slave tracing
so I looked only at the regular i2c and mctp trace paths.

> > Add an mctp_reply trace function that will be used instead.
>
> Can you elaborate a little on what you were/are looking to inspect
> here? (mainly: which packet fields are you interested in?) That will
> help to determine the best approach here.

Sure, I basically wanted to trace the i2c packet buffer in a simple way.
Although, it seems we already have that in the trace_i2c_slave since 5.18 so
it could be redundant, unless you see any other potential use for it.

Thanks,
Tal.

Hi Tal,

> > > mctp-i2c rx implementation doesn't call
> > > __i2c_transfer which calls the i2c reply trace function.
> > 
> > No, but we can trace the i2c rx path through the trace_i2c_slave
> > tracepoint. It is a little messier than tracing trace_i2c_write,
> > but
> > has been sufficient with the debugging I've needed in the past.
> 
> Oh, I missed that.
> I had to test it with an older kernel without i2c_slave tracing
> so I looked only at the regular i2c and mctp trace paths.

OK! That tracepoint was (coincidentally) added in 5.18, same as the
MCTP-over-i2c transport. So we should have coverage for both features
on upstream kernels, at least.

> > > Add an mctp_reply trace function that will be used instead.
> > 
> > Can you elaborate a little on what you were/are looking to inspect
> > here? (mainly: which packet fields are you interested in?) That
> > will
> > help to determine the best approach here.
> 
> Sure, I basically wanted to trace the i2c packet buffer in a simple
> way.

OK - did you specifically need the i2c transport headers? Since the
MCTP interfaces are regular net devices, the easiest way to trace
generic MCTP transfers is generally via a packet capture (tcpdump,
wireshark, etc).

Cheers,


Jeremy