Messages in this thread | | | Subject | Re: [RFC V2] printk: add warning while drop partial text in msg | From | Joe Perches <> | Date | Mon, 18 Sep 2017 03:00:03 -0700 |
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On Mon, 2017-09-18 at 18:39 +0900, Sergey Senozhatsky wrote: > Hi, > > On (09/12/17 14:07), pierre kuo wrote: > [..] > > int per_cpu_thread_fn(void* data) > > { > > unsigned int index = 0; > > unsigned int len = 0; > > char* local_string = kzalloc(2048, GFP_KERNEL); > > > > do { > > len += sprintf((local_string + len), "this is the %d line\n", index++); > > }while(len < 576); > > printk_deferred("%s", local_string); > > return 0; > > } > > which is not a real world example, isn't it? > > printk_deferred("%s", local_string[2048]) makes no sense anyway, > since we limit the message size to 1024 - HEADER chars in > vprintk_emit() // see static char textbuf[LOG_LINE_MAX]. > > I'm not quite following what were you trying to prove, sorry. > does any function in the upstream kernel printk()-s buffers > larger than LOG_LINE_MAX? which one? > > > - the longest line in my dmesg output is 260 bytes in total (including timestamp)
try a kernel with a few modules loaded
For instance:
$ dmesg | awk '{ print length($0), $0 }'|sort -rn | head -1 827 [337318.968616] Modules linked in: snd_usb_audio snd_usbmidi_lib ccm rfcomm bnep snd_hda_codec_hdmi dell_led snd_hda_codec_realtek snd_hda_codec_generic hid_multitouch binfmt_misc nls_iso8859_1 arc4 i2c_designware_platform i2c_designware_core dell_wmi snd_soc_skl snd_soc_skl_ipc snd_soc_sst_ipc snd_soc_sst_dsp snd_hda_ext_core snd_soc_sst_match snd_soc_core snd_compress ac97_bus snd_pcm_dmaengine snd_hda_intel dell_laptop intel_rapl snd_hda_codec dell_smbios dcdbas x86_pkg_temp_thermal snd_hda_core intel_powerclamp snd_hwdep coretemp kvm_intel snd_pcm kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel iwlmvm pcbc mac80211 snd_seq_midi snd_seq_midi_event aesni_intel aes_x86_64 crypto_simd snd_rawmidi glue_helper cryptd intel_cstate intel_rapl_perf snd_seq iwlwifi snd_seq_device uvcvideo videobuf2_vmalloc
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