On Sun, Apr 03, 2011 at 08:41:51PM +0200, David Sastre wrote: > On Sun, Apr 03, 2011 at 07:20:08PM +0200, David Sastre wrote: > > Hello, > > > > I got a kernel trace related to some I/O error. > > I'd like to debug it further, but don't not how to proceed. > > I have some basic gdb skills, but the pkg involved is the kernel, so > > I can't just run 'gdb executable trace'... > > > > The trace looks like this: > > > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554092] ------------[ cut here ]------------ > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554096] WARNING: at /build/buildd-linux-2.6_2.6.32-30-i386-UYhWt7/linux-2.6-2.6.32/debian/build/source_i386_none/fs/buffer.c:1160 mark_buffer_dirty+0x20/0x7a() > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554098] Hardware name: P55-US3L > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554099] Modules linked in: tun ipt_REJECT xt_tcpudp iptable_filter ip_tables x_tables dahdi_echocan_oslec echo wcfxo dahdi crc_ccitt ppdev lp kvm_intel kvm binfmt_misc fuse bridge stp loop saa7134_alsa tda10048 saa7134_dvb videobuf_dvb dvb_core snd_hda_codec_atihdmi snd_hda_codec_realtek tda18271 tda8290 joydev tuner usbhid hid snd_hda_intel saa7134 sg snd_hda_codec ir_common sr_mod v4l2_common videodev snd_hwdep snd_pcm_oss v4l1_compat videobuf_dma_sg snd_seq_midi snd_mixer_oss videobuf_core snd_rawmidi snd_pcm r8169 snd_seq_midi_event cdrom usb_storage snd_seq ata_generic uhci_hcd snd_timer ehci_hcd mii tulip tveeprom ata_piix usbcore snd_seq_device ahci fglrx(P) snd serio_raw pata_jmicron soundcore snd_page_alloc nls_base pcspkr i2c_i801 i2c_core evdev processor button parport_pc parport ext3 jbd mbcache dm_mod raid1 md_mod sd_mod crc_t10dif sata_via libata scsi_mod thermal thermal_sys > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554140] Pid: 18351, comm: amarok Tainted: P 2.6.32-5-686-bigmem #1 > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554142] Call Trace: > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554146] [<c103652d>] ? warn_slowpath_common+0x5e/0x8a > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554148] [<c1036563>] ? warn_slowpath_null+0xa/0xc > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554150] [<c10d5528>] ? mark_buffer_dirty+0x20/0x7a > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554157] [<f8307fac>] ? ext3_commit_super+0x40/0x56 [ext3] > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554162] [<f8309516>] ? ext3_handle_error+0x6e/0x8e [ext3] > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554166] [<f83095df>] ? ext3_error+0x3a/0x40 [ext3] > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554172] [<f8303401>] ? ext3_free_branches+0xa3/0x1e9 [ext3] > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554178] [<f8303a33>] ? ext3_truncate+0x4ec/0x70c [ext3] > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554182] [<f82c8a97>] ? journal_stop+0x254/0x260 [jbd] > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554187] [<f83041b9>] ? ext3_write_begin+0x1ac/0x1d2 [ext3] > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554191] [<c108e657>] ? generic_file_buffered_write+0xd0/0x21d > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554194] [<c108eba1>] ? __generic_file_aio_write+0x265/0x28d > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554197] [<c10c92d6>] ? touch_atime+0x69/0xd9 > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554199] [<c108ec1a>] ? generic_file_aio_write+0x51/0x93 > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554202] [<c10ba776>] ? do_sync_write+0xc0/0x107 > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554205] [<c10bd4eb>] ? cp_new_stat64+0xf7/0x109 > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554208] [<c104a322>] ? autoremove_wake_function+0x0/0x2d > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554211] [<c10bda3f>] ? sys_fstat64+0x1e/0x23 > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554214] [<c1109ce8>] ? security_file_permission+0xc/0xd > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554216] [<c10ba6b6>] ? do_sync_write+0x0/0x107 > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554217] [<c10bb0a2>] ? vfs_write+0x7e/0xd6 > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554219] [<c10bb192>] ? sys_write+0x3c/0x63 > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554222] [<c100813b>] ? sysenter_do_call+0x12/0x28 > > 2011-04-03T18:36:32+02:00 jethro kernel: : [24521.554223] ---[ end trace 20f4b55a0560b754 ]--- > > > > FWIW, I have dbg symbols installed for this kernel: > > > > ii linux-image-2.6.32-5-686-bigmem 2.6.32-30 Linux 2.6.32 for PCs with 4GB+ RAM > > ii linux-image-2.6.32-5-686-bigmem-dbg 2.6.32-31 Debugging infos for Linux 2.6.32-5-686-bigmem > > Can anybody tell me how to properly enable ddebug on a 2.6.32-5 kernel? > > I've been able to find some info regarding 2.6.38¹, but that doesn't seem > to apply to 2.6.32, as there is no /sys/kernel/debug/dynamic_debug > directory after mounting the debufgs: > > # mount -t debugfs none /sys/kernel/debug/ > # ll /sys/kernel/debug/ > total 0 > drwxr-xr-x 40 root root 0 abr 3 19:58 bdi > drwxr-xr-x 4 root root 0 abr 3 11:47 hid > drwxr-xr-x 2 root root 0 abr 3 11:47 kprobes > drwxr-xr-x 2 root root 0 abr 3 12:07 kvm > drwxr-xr-x 2 root root 0 abr 3 11:47 mce > -rw-r--r-- 1 root root 0 abr 3 11:47 sched_features > drwxr-xr-x 5 root root 0 abr 3 11:47 tracing > drwxr-xr-x 2 root root 0 abr 3 11:47 usb > drwxr-xr-x 2 root root 0 abr 3 11:47 x86 > > and therefore I can't issue: > > # echo 'file buffer.c line 1160 +p' > /sys/kernel/debug/dynamic_debug/control > > ¹http://www.mjmwired.net/kernel/Documentation/dynamic-debug-howto.txt OK. As stated in the kernel sources under Documentation/dynamic-debug-howto.txt, CONFIG_DYNAMIC_DEBUG must be set to be able to use ddebug. As it is not my case: # grep CONFIG_DYNAMIC_DEBUG config-2.6.32-5-686-bigmem # CONFIG_DYNAMIC_DEBUG is not set ...is easy to see why I don't have that dir under <debugfs> Looks like I have to recompile to debug further. -- Huella de clave primaria: 0FDA C36F F110 54F4 D42B D0EB 617D 396C 448B 31EB
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