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Date:   Wed, 3 Mar 2021 10:19:05 +0200
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Stephen Boyd <swboyd@chromium.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Jessica Yu <jeyu@kernel.org>,
        Evan Green <evgreen@chromium.org>,
        Hsin-Yi Wang <hsinyi@chromium.org>,
        Petr Mladek <pmladek@suse.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        linux-doc@vger.kernel.org
Subject: Re: [PATCH 5/7] printk: Make %pS and friends print module build ID
Message-ID: <YD9GeXcKbF3bsDLo@smile.fi.intel.com>
References: <20210301174749.1269154-1-swboyd@chromium.org>
 <20210301174749.1269154-6-swboyd@chromium.org>
 <20210302210136.3ded3ab3@gandalf.local.home>
 <161474043200.1478170.15118093304775120279@swboyd.mtv.corp.google.com>
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Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
Precedence: bulk

On Tue, Mar 02, 2021 at 07:00:32PM -0800, Stephen Boyd wrote:
> Quoting Steven Rostedt (2021-03-02 18:01:36)
> > On Mon,  1 Mar 2021 09:47:47 -0800
> > Stephen Boyd <swboyd@chromium.org> wrote:
> > 
> > >  WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARNING+0x28/0x30 [lkdtm] (ed5019fdf5e53be37cb1ba7899292d7e143b259e)
> > >  Modules linked in: lkdtm rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE
> > >  CPU: 4 PID: 3255 Comm: bash Not tainted 5.11 #3 aa23f7a1231c229de205662d5a9e0d4c580f19a1
> > >  Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
> > >  pstate: 00400009 (nzcv daif +PAN -UAO -TCO BTYPE=--)
> > >  pc : lkdtm_WARNING+0x28/0x30 [lkdtm] (ed5019fdf5e53be37cb1ba7899292d7e143b259e)
> > >  lr : lkdtm_do_action+0x24/0x40 [lkdtm] (ed5019fdf5e53be37cb1ba7899292d7e143b259e)
> > 
> > Why not just change the "Modules linked in:" portion to show the build IDs
> > instead of every function call? Maybe make it a config option to do so?
> > 
> 
> As I wrote in the commit text
> 
> │ An alternative to changing the printk format would be to update the                                                                                                                                             
> │ "Modules linked in:" line to include the build ID of each module linked                                                                                                                                         
> │ in. This can become quite long when many modules are loaded (i.e. on a                                                                                                                                          
> │ distro) so I've opted for the printk format instead.
> 
> Implementing it is fairly simple compared to a new printk format. In
> fact I did that initially but decided against it because it felt
> unreadable and provided more information than was necessary if the
> stacktrace wasn't in a module.
> 
> Example:
> 
>  Modules linked in: rfcomm 4de3e669b9fee915 algif_hash 915c61c32d476f01 algif_skcipher 53a4a330149bf071 af_alg b49d66496907f376 xt_cgroup 36fbbb65e7620df9 uinput a0ff6a06c1c53685 xt_MASQUERADE d130585f728315d2 snd_soc_sc7180 5c130cd310c81a12 venus_dec 2071e263fde9ca07 qcom_spmi_temp_alarm 41e28f2a9cc8b562 qcom_spmi_adc_tm5 7e0e48d0b6550c7a qcom_spmi_adc5 40b81a00bc2d0c1d qcom_vadc_common 09bb012dd1662dea snd_soc_rt5682_i2c c92b8935ad4a1729 venus_enc efaf3335b88287bf snd_soc_qcom_common 56d1e87c267ed02e videobuf2_dma_sg e9bc3c9e2758dfc9 snd_soc_rt5682 c4c9b31bf9a43f8b snd_soc_rl6231 908446e32436898c hci_uart 107b5fe6884df077 btqca 401a2fcc17b80a39 bluetooth 3369c881496a3cf8 venus_core a11eee3aa201ad8e ecdh_generic 883e01f98b778108 ecc 226b258cf40ad1ba v4l2_mem2mem 592f197cbad39e6b snd_soc_lpass_sc7180 42a99cb812d5e2e3 snd_soc_lpass_hdmi 95cce2160cfc58e2 snd_soc_lpass_cpu 475a4b395577affd snd_soc_lpass_platform 67517083263035ec snd_soc_max98357a 03ec1af0493d1c59
>   fuse 82d170244a4d4ac6 iio_trig_sysfs b879a6228e059834 cros_ec_lid_angle a713c5f0a06a7a82 cros_ec_sensors 03f0c142ec521f67 cros_ec_sensors_core ada3f44647980056 cros_ec_sensors_ring f99590e87e998485 industrialio_triggered_buffer c697969d67f73d77 kfifo_buf e8a3aeb3069188f0 cros_ec_sensorhub 041ed1ffcefc991b ath10k_snoc 2f60802a74ff6ca7 lzo_rle 49a6228cec0c6885 ath10k_core 9407c36a2b8f8fae lzo_compress e9b4375d4bad668a ath 20c585ba6f3998f0 zram c5cdfc1d7d8a35d9 mac80211 9eaed1c76e000c02 cfg80211 872178d2dcebb722 cdc_ether 2baa214f72289402 usbnet 2bec73d0922ade28 uvcvideo eee0352cb1846ee4 r8152 47b76561b78e9b1b mii b306d150923fe614 videobuf2_vmalloc 55431ec52fa6af84 videobuf2_memops 4d43ad18fa7b1e4e videobuf2_v4l2 cdda06b9d95ab11d videobuf2_common 69cef0ca55a70a4a joydev 148399325b72d4a0
> 
> compared to 
> 
>  Modules linked in: rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE snd_soc_sc7180 venus_dec qcom_spmi_temp_alarm qcom_spmi_adc_tm5 qcom_spmi_adc5 qcom_vadc_common snd_soc_rt5682_i2c venus_enc snd_soc_qcom_common videobuf2_dma_sg snd_soc_rt5682 snd_soc_rl6231 hci_uart btqca bluetooth venus_core ecdh_generic ecc v4l2_mem2mem snd_soc_lpass_sc7180 snd_soc_lpass_hdmi snd_soc_lpass_cpu snd_soc_lpass_platform snd_soc_max98357a 
>   fuse iio_trig_sysfs cros_ec_lid_angle cros_ec_sensors cros_ec_sensors_core cros_ec_sensors_ring industrialio_triggered_buffer kfifo_buf cros_ec_sensorhub ath10k_snoc lzo_rle ath10k_core lzo_compress ath zram mac80211 cfg80211 cdc_ether usbnet uvcvideo r8152 mii videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common joydev 
> I suppose it could be surrounded by parenthesis or brackets and that
> would be a little better? I'll try this approach again and see what
> folks think.

But you can do:
Modules linked: module1 [buildidX]
 module2 [buildidY]
 module3 [buildidZ]
...

i.o.w. one module per line.

* Yes, I understand that downside maybe split message, so it's just for
consideration.

-- 
With Best Regards,
Andy Shevchenko