If I direct kernel console output to the serial port ttyS0 by grub kernel command line like so kernel /vmlinuz-2.6.39-FLG ro root=/dev/sdb3 rootfstype=ext3 selinux=0 console=ttyS0,19200n8r console=tty0 then console output appears at the other end of the ttyS0 as expected, but then if I log in (on local tty1) and cat /proc/tty/driver/serial I get this (on 2.6.39) BUG: sleeping function called from invalid context at arch/x86/mm/fault.c:1087 and the system is dead. the line number refers to this code : /* * The above down_read_trylock() might have succeeded in * which case we'll have missed the might_sleep() from * down_read(): */ might_sleep(); This also occurs on 2.6.36 so (I would assume) many other releases as well. John Lumby ---------------------------------------------------------------------------------------- ver_linux output: (note --- the 4 CPUs are 2 cores each with SMT enabled) (note -- relevant scsi and usb mass-stg drivers are builtin) Linux lumbyont.localdomain 2.6.39-vnla #1 SMP Tue May 31 13:55:29 EDT 2011 i686 GNU/Linux Gnu C 4.5.3 Gnu make 3.81 binutils 2.21 util-linux 2.13-pre7 mount support module-init-tools 3.3-pre1 e2fsprogs 1.41.13 pcmciautils 014 quota-tools 3.13. PPP 2.4.4 isdn4k-utils 3.9 Linux C Library 2.11.1 Dynamic linker (ldd) 2.11.1 Procps 3.2.7 Net-tools 1.60 Kbd 1.12 oprofile 0.9.7git Sh-utils 8.9 udev 095 wireless-tools 29 Modules Loaded snd_hda_intel snd_hda_codec rtc_cmos rtc_core rtc_lib bridge stp llc i915 drm_kms_helper intel_agp intel_gtt tun xt_state ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 dm_mod parport_pc lp parport ============ /proc/cpuinfo ============= processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 28 model name : Intel(R) Atom(TM) CPU 330 @ 1.60GHz stepping : 2 cpu MHz : 1596.167 cache size : 512 KB physical id : 0 siblings : 4 core id : 0 cpu cores : 2 apicid : 0 initial apicid : 0 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl tm2 ssse3 cx16 xtpr pdcm movbe lahf_lm dts bogomips : 3192.33 clflush size : 64 cache_alignment : 64 address sizes : 32 bits physical, 48 bits virtual power management: processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 28 model name : Intel(R) Atom(TM) CPU 330 @ 1.60GHz stepping : 2 cpu MHz : 1596.167 cache size : 512 KB physical id : 0 siblings : 4 core id : 1 cpu cores : 2 apicid : 2 initial apicid : 2 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl tm2 ssse3 cx16 xtpr pdcm movbe lahf_lm dts bogomips : 3191.98 clflush size : 64 cache_alignment : 64 address sizes : 32 bits physical, 48 bits virtual power management: processor : 2 vendor_id : GenuineIntel cpu family : 6 model : 28 model name : Intel(R) Atom(TM) CPU 330 @ 1.60GHz stepping : 2 cpu MHz : 1596.167 cache size : 512 KB physical id : 0 siblings : 4 core id : 0 cpu cores : 2 apicid : 1 initial apicid : 1 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl tm2 ssse3 cx16 xtpr pdcm movbe lahf_lm dts bogomips : 3191.95 clflush size : 64 cache_alignment : 64 address sizes : 32 bits physical, 48 bits virtual power management: processor : 3 vendor_id : GenuineIntel cpu family : 6 model : 28 model name : Intel(R) Atom(TM) CPU 330 @ 1.60GHz stepping : 2 cpu MHz : 1596.167 cache size : 512 KB physical id : 0 siblings : 4 core id : 1 cpu cores : 2 apicid : 3 initial apicid : 3 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl tm2 ssse3 cx16 xtpr pdcm movbe lahf_lm dts bogomips : 3191.85 clflush size : 64 cache_alignment : 64 address sizes : 32 bits physical, 48 bits virtual power management: ============ /proc/modules ============= snd_hda_intel 17288 0 - Live 0xf81e5000 snd_hda_codec 49964 1 snd_hda_intel, Live 0xf81ca000 rtc_cmos 6500 0 - Live 0xf8151000 rtc_core 13963 1 rtc_cmos, Live 0xf814b000 rtc_lib 1765 1 rtc_core, Live 0xf80d0000 bridge 56404 0 - Live 0xf80b9000 stp 1136 1 bridge, Live 0xf80b3000 llc 2864 2 bridge,stp, Live 0xf8005000 i915 297997 1 - Live 0xf80e5000 drm_kms_helper 24000 1 i915, Live 0xf80d8000 intel_agp 8367 1 i915, Live 0xf8c10000 intel_gtt 11161 3 i915,intel_agp, Live 0xf8bd7000 tun 12525 1 - Live 0xf8b98000 xt_state 867 26 - Live 0xf8b44000 ipt_MASQUERADE 1358 1 - Live 0xf8ae6000 iptable_nat 3543 1 - Live 0xf8aa6000 nf_nat 11151 2 ipt_MASQUERADE,iptable_nat, Live 0xf8a3a000 nf_conntrack_ipv4 8405 29 iptable_nat,nf_nat, Live 0xf8910000 nf_conntrack 40997 5 xt_state,ipt_MASQUERADE,iptable_nat,nf_nat,nf_conntrack_ipv4, Live 0xf8868000 nf_defrag_ipv4 887 1 nf_conntrack_ipv4, Live 0xf8696000 dm_mod 52766 0 - Live 0xf8350000 parport_pc 17355 1 - Live 0xf81de000 lp 6716 0 - Live 0xf802b000 parport 24631 2 parport_pc,lp, Live 0xf8159000 ============ /proc/ioports ============= 0000-0cf7 : PCI Bus 0000:00 0000-001f : dma1 0020-0021 : pic1 0040-0043 : timer0 0050-0053 : timer1 0060-0060 : keyboard 0064-0064 : keyboard 0070-0071 : rtc0 0080-008f : dma page reg 00a0-00a1 : pic2 00c0-00df : dma2 00f0-00ff : fpu 0170-0177 : 0000:00:1f.1 0170-0177 : piix 01f0-01f7 : 0000:00:1f.1 01f0-01f7 : piix 0376-0376 : 0000:00:1f.1 0376-0376 : piix 0378-037a : parport0 037b-037f : parport0 03c0-03df : vga+ 03f6-03f6 : 0000:00:1f.1 03f6-03f6 : piix 03f8-03ff : serial 0400-047f : pnp 00:06 0400-0403 : ACPI PM1a_EVT_BLK 0404-0405 : ACPI PM1a_CNT_BLK 0408-040b : ACPI PM_TMR 0410-0415 : ACPI CPU throttle 0420-0420 : ACPI PM2_CNT_BLK 0428-042f : ACPI GPE0_BLK 0500-053f : pnp 00:06 0680-06ff : pnp 00:06 0cf8-0cff : PCI conf1 0d00-ffff : PCI Bus 0000:00 1000-1fff : PCI Bus 0000:04 1000-10ff : 0000:04:00.0 2000-2fff : PCI Bus 0000:01 2000-20ff : 0000:01:00.0 3000-301f : 0000:00:1f.3 3000-301f : i801_smbus 3020-303f : 0000:00:1d.3 3040-305f : 0000:00:1d.2 3060-307f : 0000:00:1d.1 3080-309f : 0000:00:1d.0 30a0-30af : 0000:00:1f.2 30a0-30af : ata_piix 30b0-30bf : 0000:00:1f.1 30b0-30bf : piix 30c0-30c7 : 0000:00:1f.2 30c0-30c7 : ata_piix 30c8-30cf : 0000:00:1f.2 30c8-30cf : ata_piix 30e0-30e7 : 0000:00:02.0 30e8-30eb : 0000:00:1f.2 30e8-30eb : ata_piix 30ec-30ef : 0000:00:1f.2 30ec-30ef : ata_piix 4000-4fff : PCI Bus 0000:03 5000-5fff : PCI Bus 0000:02 ============ /proc/iomem ============= 00000000-0000ffff : reserved 00010000-0008efff : System RAM 0008f000-0009ffff : reserved 000a0000-000bffff : PCI Bus 0000:00 000a0000-000bffff : Video RAM area 000c0000-000c7fff : Video ROM 000cb000-000cbfff : Adapter ROM 000e0000-000fffff : reserved 000e0000-000effff : PCI Bus 0000:00 000f0000-000fffff : System ROM 00100000-7f531fff : System RAM 01000000-0141a980 : Kernel code 0141a981-0159cabf : Kernel data 0160d000-0166cfff : Kernel bss 7f532000-7f539fff : reserved 7f53a000-7f5cafff : System RAM 7f5cb000-7f5cefff : reserved 7f5cf000-7f65ffff : System RAM 7f660000-7f6effff : ACPI Non-volatile Storage 7f6f0000-7f6f1fff : System RAM 7f6f2000-7f6fefff : ACPI Tables 7f6ff000-7f6fffff : System RAM 7f700000-7fffffff : reserved 80000000-ffffffff : reserved 80000000-f0000000 : PCI Bus 0000:00 80000000-8fffffff : 0000:00:02.0 90000000-900fffff : PCI Bus 0000:01 90000000-9000ffff : 0000:01:00.0 90020000-9003ffff : 0000:01:00.0 90100000-901fffff : PCI Bus 0000:04 90100000-901000ff : 0000:04:00.0 90200000-902fffff : PCI Bus 0000:01 90200000-90200fff : 0000:01:00.0 90300000-9037ffff : 0000:00:02.0 90380000-903bffff : 0000:00:02.0 903c0000-903c3fff : 0000:00:1b.0 903c0000-903c3fff : ICH HD audio 903c4000-903c43ff : 0000:00:1d.7 903c4000-903c43ff : ehci_hcd 90400000-904fffff : PCI Bus 0000:04 90400000-9040ffff : 0000:04:00.0 90500000-906fffff : PCI Bus 0000:03 90700000-908fffff : PCI Bus 0000:03 90900000-90afffff : PCI Bus 0000:02 90b00000-90cfffff : PCI Bus 0000:02 f8000000-febfffff : PCI Bus 0000:00 fec00000-fec003ff : IOAPIC 0 fed00000-fed003ff : HPET 0 fed13000-fed13fff : pnp 00:01 fed14000-fed17fff : pnp 00:01 fed18000-fed18fff : pnp 00:01 fed19000-fed19fff : pnp 00:01 fed1c000-fed1ffff : pnp 00:01 fed20000-fed3ffff : pnp 00:01 fed45000-fed99fff : pnp 00:01 fee00000-fee00fff : Local APIC ============ /proc/scsi/scsi ============= Attached devices: Host: scsi0 Channel: 00 Id: 00 Lun: 00 Vendor: ATA Model: WDC WD5000AAKS-6 Rev: 05.0 Type: Direct-Access ANSI SCSI revision: 05 Host: scsi1 Channel: 00 Id: 00 Lun: 00 Vendor: ATA Model: WDC WD5000AAKS-6 Rev: 05.0 Type: Direct-Access ANSI SCSI revision: 05 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
