Kernel oops and 100% CPU usage on fbt:isofs:: probes

[OmegaPhil]

dtrace: commit d663d2d, Sat Aug 18 16:24:10 2012 +0100
uname -a: Linux debian-testing-vm 3.2.0-3-amd64 #1 SMP Mon Jul 23 02:45:17 UTC 2012 x86_64 GNU/Linux

I am currently trying out dtrace in my Debian virtual machine (Debian Wheezy/Testing) via Virtualbox in order to probe anything that goes on in the isofs kernel module (trying to find out more about a hang).

After loading the module (sudo modprobe -v isofs) I run the following trivial script (my first):

#!/usr/sbin/dtrace -s


/* Intercepting all isofs function entries and exits */
fbt:isofs::
{
        trace("worked!");
        exit(0);
        /*printf("%s %s", probefunc, probename);*/
}

Originally I had the normal printf line, but thats commented out to test this in general. When the above script is ran, the following kernel oops happens:

Aug 19 19:44:36 debian-testing-vm kernel: [  146.857394] dtracedrv: module license 'CDDL' taints kernel.
Aug 19 19:44:36 debian-testing-vm kernel: [  146.857402] Disabling lock debugging due to kernel taint
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883607] Pid: 3198, comm: insmod Tainted: P           O 3.2.0-3-amd64 #1
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883614] Call Trace:
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883689]  [<ffffffffa052e001>] ? mutex_enter_common+0x27/0xcb [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883758]  [<ffffffffa0524807>] ? par_alloc+0x1f/0xc6 [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883798]  [<ffffffffa052b473>] ? fbt_provide_module+0x34/0x23e [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883808]  [<ffffffff8124d0e2>] ? device_create_vargs+0x86/0xbe
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883816]  [<ffffffff81036457>] ? should_resched+0x5/0x23
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883825]  [<ffffffff813499cf>] ? _cond_resched+0x7/0x1c
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883830]  [<ffffffff81036457>] ? should_resched+0x5/0x23
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883836]  [<ffffffff813499cf>] ? _cond_resched+0x7/0x1c
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883842]  [<ffffffff8134a1b0>] ? mutex_lock+0xd/0x2d
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883883]  [<ffffffffa050c86e>] ? dtrace_module_loaded+0x92/0x10d [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883891]  [<ffffffff8134dcd6>] ? notifier_call_chain+0x2e/0x5b
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883897]  [<ffffffff81036457>] ? should_resched+0x5/0x23
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883904]  [<ffffffff81063261>] ? __blocking_notifier_call_chain+0x48/0x5e
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883912]  [<ffffffff81074f6e>] ? sys_init_module+0x1b6/0x25b
Aug 19 19:44:36 debian-testing-vm kernel: [  146.883919]  [<ffffffff8134fc92>] ? system_call_fastpath+0x16/0x1b
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880448] BUG: unable to handle kernel paging request at ffffffffa0182086
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880453] IP: [<ffffffffa052b91a>] fbt_enable+0x5b/0x6a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880464] PGD 1607067 PUD 160b063 PMD 3745b067 PTE 0
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880468] Oops: 0002 [#1] SMP 
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880470] CPU 0 
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880471] Modules linked in: isofs dtracedrv(P) vboxsf(O) pci_stub vboxpci(O) vboxnetadp(O) vboxnetflt(O) vboxdrv(O) mperf cpufreq_stats cpufreq_conservative cpufreq_userspace cpufreq_powers
ave ppdev lp vboxvideo(O) drm rfcomm bnep bluetooth rfkill binfmt_misc fuse vhba(O) loop joydev i2c_piix4 snd_intel8x0 snd_ac97_codec snd_pcm snd_page_alloc snd_seq snd_seq_device snd_timer snd soundcore i2c_core ac97_bus parport_pc psmo
use ac serio_raw power_supply parport button processor evdev thermal_sys pcspkr vboxguest(O) ext4 crc16 jbd2 mbcache usbhid hid sd_mod crc_t10dif sr_mod cdrom ata_generic ata_piix ahci libahci ohci_hcd ehci_hcd e1000 libata usbcore scsi_
mod usb_common [last unloaded: scsi_wait_scan]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880507] 
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880509] Pid: 3225, comm: isofs_tracing.d Tainted: P           O 3.2.0-3-amd64 #1 innotek GmbH VirtualBox
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880512] RIP: 0010:[<ffffffffa052b91a>]  [<ffffffffa052b91a>] fbt_enable+0x5b/0x6a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880520] RSP: 0018:ffff88003c965898  EFLAGS: 00010202
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880522] RAX: ffffffffa0182086 RBX: ffff88001e0c97c0 RCX: 0000000000000002
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880524] RDX: 7fffffffffffffcc RSI: ffff88003c965848 RDI: 000000003745b067
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880525] RBP: ffff88001e0c9740 R08: ffff880000000c18 R09: ffff88000160b800
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880526] R10: ffff88001e118ff8 R11: 0000000000000000 R12: ffff88003744ffc0
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880528] R13: 0000000000000000 R14: ffff88001e091600 R15: ffffffffa05194e1
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880536] FS:  00007fd4d9c4b700(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880538] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880539] CR2: ffffffffa0182086 CR3: 000000001e118000 CR4: 00000000000006f0
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880543] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880545] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880546] Process isofs_tracing.d (pid: 3225, threadinfo ffff88003c964000, task ffff88003cede180)
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880548] Stack:
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880549]  ffff88001bfffd40 ffffffffa051b02d ffff88001e018200 0000000000000007
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880552]  ffff880000000006 ffff88001e0e66c0 ffff88001e0182c0 ffffffffa050c0da
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880555]  0000000000000006 ffff88003c9659f0 0000000000000007 ffff8800265bc300
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880557] Call Trace:
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880564]  [<ffffffffa051b02d>] ? dtrace_ecb_create_enable+0x1b4c/0x1be0 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880574]  [<ffffffffa050c0da>] ? dtrace_match_probe+0x8c/0xa6 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880579]  [<ffffffffa05194e1>] ? dtrace_ecb_destroy+0x555/0x555 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880585]  [<ffffffffa050c2ec>] ? dtrace_match+0x1f8/0x226 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880590]  [<ffffffff810eb6e5>] ? __kmalloc+0x100/0x112
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880596]  [<ffffffffa052456b>] ? kmem_zalloc+0x2e/0x54 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880602]  [<ffffffffa051b231>] ? dtrace_probe_enable+0x170/0x177 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880608]  [<ffffffffa050e34f>] ? dtrace_strcmp+0x1b/0x1b [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880613]  [<ffffffffa050e34f>] ? dtrace_strcmp+0x1b/0x1b [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880618]  [<ffffffffa0508f03>] ? dtrace_match_glob+0x199/0x199 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880623]  [<ffffffffa0508f03>] ? dtrace_match_glob+0x199/0x199 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880628]  [<ffffffffa051b372>] ? dtrace_enabling_match+0x13a/0x1ca [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880634]  [<ffffffffa0520fe5>] ? dtrace_ioctl+0xc3e/0x217a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880637]  [<ffffffff810cd779>] ? pte_offset_kernel+0x16/0x35
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880644]  [<ffffffff810c926a>] ? zone_page_state_add+0x14/0x23
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880647]  [<ffffffff810c9ec0>] ? __inc_zone_state+0x41/0x49
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880650]  [<ffffffff810ca0dd>] ? zone_statistics+0x41/0x74
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880653]  [<ffffffff810ba446>] ? get_page_from_freelist+0x57a/0x665
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880656]  [<ffffffff810bad51>] ? __alloc_pages_nodemask+0x6bf/0x726
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880659]  [<ffffffff810b3c44>] ? find_get_page+0x40/0x63
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880661]  [<ffffffff81036457>] ? should_resched+0x5/0x23
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880665]  [<ffffffff813499cf>] ? _cond_resched+0x7/0x1c
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880668]  [<ffffffff810b5aa8>] ? filemap_fault+0x1e6/0x33e
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880671]  [<ffffffff810f5ef5>] ? lookup_page_cgroup+0x2d/0x42
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880673]  [<ffffffff810f18d1>] ? mem_cgroup_update_page_stat+0x17/0xd4
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880676]  [<ffffffff810cdecd>] ? __do_fault+0x371/0x3ac
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880678]  [<ffffffff810d019f>] ? handle_pte_fault+0x298/0x79f
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880680]  [<ffffffff810cd779>] ? pte_offset_kernel+0x16/0x35
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880687]  [<ffffffffa0523c2e>] ? dtracedrv_ioctl.isra.3+0x3c/0x4d [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880693]  [<ffffffffa0523c4f>] ? dtracedrv_unlocked_ioctl+0x6/0xa [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880697]  [<ffffffff81106911>] ? do_vfs_ioctl+0x459/0x49a
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880699]  [<ffffffff81036457>] ? should_resched+0x5/0x23
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880702]  [<ffffffff810d3612>] ? remove_vma+0x64/0x6b
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880704]  [<ffffffff810d47c7>] ? do_munmap+0x2da/0x2f3
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880706]  [<ffffffff8110699d>] ? sys_ioctl+0x4b/0x72
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880710]  [<ffffffff8134fc92>] ? system_call_fastpath+0x16/0x1b
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880714] Code: 54 a0 48 8b 73 08 31 c0 e8 ff 92 00 00 48 8b 7b 08 ba 01 00 00 00 be 01 00 00 00 e8 8e 8e ff ff 85 c0 74 09 48 8b 43 08 8a 53 12 <88> 10 48 8b 5b 48 48 85 db 75 b0 31 c0 5b c3 41 56 41 89 d6 41 
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880737] RIP  [<ffffffffa052b91a>] fbt_enable+0x5b/0x6a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880744]  RSP <ffff88003c965898>
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880745] CR2: ffffffffa0182086
Aug 19 19:44:56 debian-testing-vm kernel: [  166.880747] ---[ end trace b484dd282d33d09e ]---

Something (no process name) then uses 100% kernel mode time on one CPU, and dtrace ignores SIGINT - time to reboot.

[dtrace4linux]

Hello OmegaPhil

interesting. Are you having success for things which have not been
modprobe'd after the dtrace module?

On 19 August 2012 20:14, OmegaPhil notifications@github.com wrote:

dtrace: commit d663d2dhttps://github.com/dtrace4linux/linux/commit/d663d2dde5c56f79494306b50411d6a2e740e0e1,
Sat Aug 18 16:24:10 2012 +0100
uname -a: Linux debian-testing-vm 3.2.0-3-amd64 #1https://github.com/dtrace4linux/linux/issues/1SMP Mon Jul 23 02:45:17 UTC 2012 x86_64 GNU/Linux

I am currently trying out dtrace in my Debian virtual machine via
Virtualbox in order to probe anything that goes on in the isofs kernel
module (trying to find out more about a hang).

After loading the module (sudo modprobe -v isofs) I run the following
trivial script (my first):

#!/usr/sbin/dtrace -s

/* Intercepting all isofs function entries and exits _/
fbt:isofs::
{
trace("worked!");
exit(0);
/_printf("%s %s", probefunc, probename);*/
}

Originally I had the normal printf line, but thats commented out to test
this in general. When the above script is ran, the following kernel oops
happens:

Aug 19 19:44:36 debian-testing-vm kernel: [ 146.857394] dtracedrv: module license 'CDDL' taints kernel.
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.857402] Disabling lock debugging due to kernel taint
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883607] Pid: 3198, comm: insmod Tainted: P O 3.2.0-3-amd64 #1
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883614] Call Trace:
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883689] [] ? mutex_enter_common+0x27/0xcb [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883758] [] ? par_alloc+0x1f/0xc6 [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883798] [] ? fbt_provide_module+0x34/0x23e [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883808] [] ? device_create_vargs+0x86/0xbe
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883816] [] ? should_resched+0x5/0x23
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883825] [] ? _cond_resched+0x7/0x1c
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883830] [] ? should_resched+0x5/0x23
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883836] [] ? _cond_resched+0x7/0x1c
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883842] [] ? mutex_lock+0xd/0x2d
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883883] [] ? dtrace_module_loaded+0x92/0x10d [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883891] [] ? notifier_call_chain+0x2e/0x5b
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883897] [] ? should_resched+0x5/0x23
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883904] [] ? _blocking_notifier_call_chain+0x48/0x5e
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883912] [] ? sys_init_module+0x1b6/0x25b
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883919] [] ? system_call_fastpath+0x16/0x1b
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880448] BUG: unable to handle kernel paging request at ffffffffa0182086
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880453] IP: [] fbt_enable+0x5b/0x6a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880464] PGD 1607067 PUD 160b063 PMD 3745b067 PTE 0
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880468] Oops: 0002 [#1] SMP
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880470] CPU 0
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880471] Modules linked in: isofs dtracedrv(P) vboxsf(O) pci_stub vboxpci(O) vboxnetadp(O) vboxnetflt(O) vboxdrv(O) mperf cpufreq_stats cpufreq_conservative cpufreq_userspace cpufreq_powers
ave ppdev lp vboxvideo(O) drm rfcomm bnep bluetooth rfkill binfmt_misc fuse vhba(O) loop joydev i2c_piix4 snd_intel8x0 snd_ac97_codec snd_pcm snd_page_alloc snd_seq snd_seq_device snd_timer snd soundcore i2c_core ac97_bus parport_pc psmo
use ac serio_raw power_supply parport button processor evdev thermal_sys pcspkr vboxguest(O) ext4 crc16 jbd2 mbcache usbhid hid sd_mod crc_t10dif sr_mod cdrom ata_generic ata_piix ahci libahci ohci_hcd ehci_hcd e1000 libata usbcore scsi
mod usb_common [last unloaded: scsi_wait_scan]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880507]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880509] Pid: 3225, comm: isofs_tracing.d Tainted: P O 3.2.0-3-amd64 #1 innotek GmbH VirtualBox
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880512] RIP: 0010:[] [] fbt_enable+0x5b/0x6a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880520] RSP: 0018:ffff88003c965898 EFLAGS: 00010202
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880522] RAX: ffffffffa0182086 RBX: ffff88001e0c97c0 RCX: 0000000000000002
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880524] RDX: 7fffffffffffffcc RSI: ffff88003c965848 RDI: 000000003745b067
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880525] RBP: ffff88001e0c9740 R08: ffff880000000c18 R09: ffff88000160b800
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880526] R10: ffff88001e118ff8 R11: 0000000000000000 R12: ffff88003744ffc0
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880528] R13: 0000000000000000 R14: ffff88001e091600 R15: ffffffffa05194e1
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880536] FS: 00007fd4d9c4b700(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880538] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880539] CR2: ffffffffa0182086 CR3: 000000001e118000 CR4: 00000000000006f0
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880543] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880545] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880546] Process isofs_tracing.d (pid: 3225, threadinfo ffff88003c964000, task ffff88003cede180)
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880548] Stack:
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880549] ffff88001bfffd40 ffffffffa051b02d ffff88001e018200 0000000000000007
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880552] ffff880000000006 ffff88001e0e66c0 ffff88001e0182c0 ffffffffa050c0da
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880555] 0000000000000006 ffff88003c9659f0 0000000000000007 ffff8800265bc300
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880557] Call Trace:
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880564] [] ? dtrace_ecb_create_enable+0x1b4c/0x1be0 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880574] [] ? dtrace_match_probe+0x8c/0xa6 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880579] [] ? dtrace_ecb_destroy+0x555/0x555 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880585] [] ? dtrace_match+0x1f8/0x226 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880590] [] ? __kmalloc+0x100/0x112
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880596] [] ? kmem_zalloc+0x2e/0x54 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880602] [] ? dtrace_probe_enable+0x170/0x177 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880608] [] ? dtrace_strcmp+0x1b/0x1b [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880613] [] ? dtrace_strcmp+0x1b/0x1b [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880618] [] ? dtrace_match_glob+0x199/0x199 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880623] [] ? dtrace_match_glob+0x199/0x199 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880628] [] ? dtrace_enabling_match+0x13a/0x1ca [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880634] [] ? dtrace_ioctl+0xc3e/0x217a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880637] [] ? pte_offset_kernel+0x16/0x35
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880644] [] ? zone_page_state_add+0x14/0x23
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880647] [] ? __inc_zone_state+0x41/0x49
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880650] [] ? zone_statistics+0x41/0x74
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880653] [] ? get_page_from_freelist+0x57a/0x665
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880656] [] ? __alloc_pages_nodemask+0x6bf/0x726
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880659] [] ? find_get_page+0x40/0x63
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880661] [] ? should_resched+0x5/0x23
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880665] [] ? _cond_resched+0x7/0x1c
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880668] [] ? filemap_fault+0x1e6/0x33e
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880671] [] ? lookup_page_cgroup+0x2d/0x42
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880673] [] ? mem_cgroup_update_page_stat+0x17/0xd4
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880676] [] ? __do_fault+0x371/0x3ac
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880678] [] ? handle_pte_fault+0x298/0x79f
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880680] [] ? pte_offset_kernel+0x16/0x35
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880687] [] ? dtracedrv_ioctl.isra.3+0x3c/0x4d [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880693] [] ? dtracedrv_unlocked_ioctl+0x6/0xa [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880697] [] ? do_vfs_ioctl+0x459/0x49a
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880699] [] ? should_resched+0x5/0x23
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880702] [] ? remove_vma+0x64/0x6b
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880704] [] ? do_munmap+0x2da/0x2f3
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880706] [] ? sys_ioctl+0x4b/0x72
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880710] [] ? system_call_fastpath+0x16/0x1b
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880714] Code: 54 a0 48 8b 73 08 31 c0 e8 ff 92 00 00 48 8b 7b 08 ba 01 00 00 00 be 01 00 00 00 e8 8e 8e ff ff 85 c0 74 09 48 8b 43 08 8a 53 12 <88> 10 48 8b 5b 48 48 85 db 75 b0 31 c0 5b c3 41 56 41 89 d6 41
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880737] RIP [] fbt_enable+0x5b/0x6a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880744] RSP
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880745] CR2: ffffffffa0182086
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880747] ---[ end trace b484dd282d33d09e ]---

Something (no process name) then uses 100% kernel mode time on one CPU,
and dtrace ignores SIGINT - time to reboot.

�
Reply to this email directly or view it on GitHubhttps://github.com//issues/40.

[dtrace4linux]

I just reproduced on deb6-64 - worked fine on Ubuntu....off to debug.

On 19 August 2012 20:22, Paul Fox paul.d.fox@gmail.com wrote:

Hello OmegaPhil

interesting. Are you having success for things which have not been
modprobe'd after the dtrace module?

On 19 August 2012 20:14, OmegaPhil notifications@github.com wrote:

dtrace: commit d663d2dhttps://github.com/dtrace4linux/linux/commit/d663d2dde5c56f79494306b50411d6a2e740e0e1,
Sat Aug 18 16:24:10 2012 +0100
uname -a: Linux debian-testing-vm 3.2.0-3-amd64 #1https://github.com/dtrace4linux/linux/issues/1SMP Mon Jul 23 02:45:17 UTC 2012 x86_64 GNU/Linux

I am currently trying out dtrace in my Debian virtual machine via
Virtualbox in order to probe anything that goes on in the isofs kernel
module (trying to find out more about a hang).

After loading the module (sudo modprobe -v isofs) I run the following
trivial script (my first):

#!/usr/sbin/dtrace -s

/* Intercepting all isofs function entries and exits _/
fbt:isofs::
{
trace("worked!");
exit(0);
/_printf("%s %s", probefunc, probename);*/
}

Originally I had the normal printf line, but thats commented out to test
this in general. When the above script is ran, the following kernel oops
happens:

Aug 19 19:44:36 debian-testing-vm kernel: [ 146.857394] dtracedrv: module license 'CDDL' taints kernel.
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.857402] Disabling lock debugging due to kernel taint
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883607] Pid: 3198, comm: insmod Tainted: P O 3.2.0-3-amd64 #1
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883614] Call Trace:
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883689] [] ? mutex_enter_common+0x27/0xcb [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883758] [] ? par_alloc+0x1f/0xc6 [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883798] [] ? fbt_provide_module+0x34/0x23e [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883808] [] ? device_create_vargs+0x86/0xbe
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883816] [] ? should_resched+0x5/0x23
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883825] [] ? _cond_resched+0x7/0x1c
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883830] [] ? should_resched+0x5/0x23
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883836] [] ? _cond_resched+0x7/0x1c
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883842] [] ? mutex_lock+0xd/0x2d
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883883] [] ? dtrace_module_loaded+0x92/0x10d [dtracedrv]
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883891] [] ? notifier_call_chain+0x2e/0x5b
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883897] [] ? should_resched+0x5/0x23
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883904] [] ? _blocking_notifier_call_chain+0x48/0x5e
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883912] [] ? sys_init_module+0x1b6/0x25b
Aug 19 19:44:36 debian-testing-vm kernel: [ 146.883919] [] ? system_call_fastpath+0x16/0x1b
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880448] BUG: unable to handle kernel paging request at ffffffffa0182086
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880453] IP: [] fbt_enable+0x5b/0x6a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880464] PGD 1607067 PUD 160b063 PMD 3745b067 PTE 0
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880468] Oops: 0002 [#1] SMP
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880470] CPU 0
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880471] Modules linked in: isofs dtracedrv(P) vboxsf(O) pci_stub vboxpci(O) vboxnetadp(O) vboxnetflt(O) vboxdrv(O) mperf cpufreq_stats cpufreq_conservative cpufreq_userspace cpufreq_powers
ave ppdev lp vboxvideo(O) drm rfcomm bnep bluetooth rfkill binfmt_misc fuse vhba(O) loop joydev i2c_piix4 snd_intel8x0 snd_ac97_codec snd_pcm snd_page_alloc snd_seq snd_seq_device snd_timer snd soundcore i2c_core ac97_bus parport_pc psmo
use ac serio_raw power_supply parport button processor evdev thermal_sys pcspkr vboxguest(O) ext4 crc16 jbd2 mbcache usbhid hid sd_mod crc_t10dif sr_mod cdrom ata_generic ata_piix ahci libahci ohci_hcd ehci_hcd e1000 libata usbcore scsi
mod usb_common [last unloaded: scsi_wait_scan]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880507]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880509] Pid: 3225, comm: isofs_tracing.d Tainted: P O 3.2.0-3-amd64 #1 innotek GmbH VirtualBox
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880512] RIP: 0010:[] [] fbt_enable+0x5b/0x6a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880520] RSP: 0018:ffff88003c965898 EFLAGS: 00010202
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880522] RAX: ffffffffa0182086 RBX: ffff88001e0c97c0 RCX: 0000000000000002
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880524] RDX: 7fffffffffffffcc RSI: ffff88003c965848 RDI: 000000003745b067
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880525] RBP: ffff88001e0c9740 R08: ffff880000000c18 R09: ffff88000160b800
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880526] R10: ffff88001e118ff8 R11: 0000000000000000 R12: ffff88003744ffc0
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880528] R13: 0000000000000000 R14: ffff88001e091600 R15: ffffffffa05194e1
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880536] FS: 00007fd4d9c4b700(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880538] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880539] CR2: ffffffffa0182086 CR3: 000000001e118000 CR4: 00000000000006f0
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880543] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880545] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880546] Process isofs_tracing.d (pid: 3225, threadinfo ffff88003c964000, task ffff88003cede180)
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880548] Stack:
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880549] ffff88001bfffd40 ffffffffa051b02d ffff88001e018200 0000000000000007
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880552] ffff880000000006 ffff88001e0e66c0 ffff88001e0182c0 ffffffffa050c0da
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880555] 0000000000000006 ffff88003c9659f0 0000000000000007 ffff8800265bc300
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880557] Call Trace:
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880564] [] ? dtrace_ecb_create_enable+0x1b4c/0x1be0 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880574] [] ? dtrace_match_probe+0x8c/0xa6 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880579] [] ? dtrace_ecb_destroy+0x555/0x555 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880585] [] ? dtrace_match+0x1f8/0x226 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880590] [] ? __kmalloc+0x100/0x112
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880596] [] ? kmem_zalloc+0x2e/0x54 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880602] [] ? dtrace_probe_enable+0x170/0x177 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880608] [] ? dtrace_strcmp+0x1b/0x1b [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880613] [] ? dtrace_strcmp+0x1b/0x1b [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880618] [] ? dtrace_match_glob+0x199/0x199 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880623] [] ? dtrace_match_glob+0x199/0x199 [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880628] [] ? dtrace_enabling_match+0x13a/0x1ca [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880634] [] ? dtrace_ioctl+0xc3e/0x217a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880637] [] ? pte_offset_kernel+0x16/0x35
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880644] [] ? zone_page_state_add+0x14/0x23
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880647] [] ? __inc_zone_state+0x41/0x49
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880650] [] ? zone_statistics+0x41/0x74
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880653] [] ? get_page_from_freelist+0x57a/0x665
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880656] [] ? __alloc_pages_nodemask+0x6bf/0x726
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880659] [] ? find_get_page+0x40/0x63
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880661] [] ? should_resched+0x5/0x23
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880665] [] ? _cond_resched+0x7/0x1c
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880668] [] ? filemap_fault+0x1e6/0x33e
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880671] [] ? lookup_page_cgroup+0x2d/0x42
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880673] [] ? mem_cgroup_update_page_stat+0x17/0xd4
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880676] [] ? __do_fault+0x371/0x3ac
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880678] [] ? handle_pte_fault+0x298/0x79f
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880680] [] ? pte_offset_kernel+0x16/0x35
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880687] [] ? dtracedrv_ioctl.isra.3+0x3c/0x4d [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880693] [] ? dtracedrv_unlocked_ioctl+0x6/0xa [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880697] [] ? do_vfs_ioctl+0x459/0x49a
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880699] [] ? should_resched+0x5/0x23
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880702] [] ? remove_vma+0x64/0x6b
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880704] [] ? do_munmap+0x2da/0x2f3
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880706] [] ? sys_ioctl+0x4b/0x72
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880710] [] ? system_call_fastpath+0x16/0x1b
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880714] Code: 54 a0 48 8b 73 08 31 c0 e8 ff 92 00 00 48 8b 7b 08 ba 01 00 00 00 be 01 00 00 00 e8 8e 8e ff ff 85 c0 74 09 48 8b 43 08 8a 53 12 <88> 10 48 8b 5b 48 48 85 db 75 b0 31 c0 5b c3 41 56 41 89 d6 41
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880737] RIP [] fbt_enable+0x5b/0x6a [dtracedrv]
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880744] RSP
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880745] CR2: ffffffffa0182086
Aug 19 19:44:56 debian-testing-vm kernel: [ 166.880747] ---[ end trace b484dd282d33d09e ]---

Something (no process name) then uses 100% kernel mode time on one CPU,
and dtrace ignores SIGINT - time to reboot.

�
Reply to this email directly or view it on GitHubhttps://github.com//issues/40.

[OmegaPhil]

Ha, wow, thanks for the fast feedback! Your last message came as I was just hacking together my first basic 'commandline' script:

dtrace -n 'proc:::start,proc:::exit { printf("Process: %s %s", execname, probename); }'

Works perfectly. Just say if you want me to test anything. If you use IRC, I'm OmegaPhil on Freenode, if you want faster feedback.

Cheers

[dtrace4linux]

Hello Phil

i've tracked the issue down to the way modules are loaded; when dtrace is
loaded, it gets the callback as the module loads, but some of the pages in
a module are freed (the .init section) but dtrace doesnt know this. I found

cat /proc/dtrace/fbt

will give a GPF for functions no longer in memory, so now I have something
to debug.

I wont get around to fixing tonite - maybe in next day or two, so just be
careful of modprobes; if you unload dtrace and reload after the new module,
everything should be fine.

(Im normally on google chat).

Have fun!

On 19 August 2012 20:30, OmegaPhil notifications@github.com wrote:

Ha, wow, thanks for the fast feedback! Your last message came as I was
just hacking together my first basic 'commandline' script:

execname, probename); }'

Works perfectly. Just say if you want me to test anything. If you use IRC,
I'm OmegaPhil on Freenode, if you want faster feedback.

Cheers

—
Reply to this email directly or view it on GitHubhttps://github.com/dtrace4linux/linux/issues/40#issuecomment-7855970.

[OmegaPhil]

Excellent, thanks for the workaround - should be fine (I'm basically a n00b doing my first kernel dive, looked into dtrace today).

[OmegaPhil]

Works great - heres the output when mount locks up with 100% kernel mode on trying to mount a presumably bad iso9660 filesystem:

dtrace: script './isofs_tracing.d' matched 96 probes
CPU     ID                    FUNCTION:NAME
  0 262919                isofs_mount:entry isofs_mount entry
  0 262920           isofs_fill_super:entry isofs_fill_super entry
  0 262934                   sb_bread:entry sb_bread entry
  0 262935                     brelse:entry brelse entry
  0 262936                    brelse:return brelse return
  0 262934                   sb_bread:entry sb_bread entry
  0 262935                     brelse:entry brelse entry
  0 262935                     brelse:entry brelse entry
  0 262995                 isofs_iget:entry isofs_iget entry
  0 262932          isofs_alloc_inode:entry isofs_alloc_inode entry
  0 262937                  init_once:entry init_once entry
  0 262937                  init_once:entry init_once entry
  0 262937                  init_once:entry init_once entry
  0 262937                  init_once:entry init_once entry
  0 262937                  init_once:entry init_once entry
  0 262937                  init_once:entry init_once entry
  0 262933         isofs_alloc_inode:return isofs_alloc_inode return
  0 262917            isofs_iget5_set:entry isofs_iget5_set entry
  0 262918           isofs_iget5_set:return isofs_iget5_set return
  0 262934                   sb_bread:entry sb_bread entry

Never returns from sb_bread presumably. Now to see how to work kgdb!

[dtrace4linux]

Just a note to say I fixed the driver loading issue.

Interested to see how you get on with this issue, and if dtrace helps you.

thanks

On 19 August 2012 22:29, OmegaPhil notifications@github.com wrote:

Works great - heres the output when mount locks up with 100% kernel mode
on trying to mount a presumably bad iso9660 filesystem:

dtrace: script './isofs_tracing.d' matched 96 probes
CPU ID FUNCTION:NAME
0 262919 isofs_mount:entry isofs_mount entry
0 262920 isofs_fill_super:entry isofs_fill_super entry
0 262934 sb_bread:entry sb_bread entry
0 262935 brelse:entry brelse entry
0 262936 brelse:return brelse return
0 262934 sb_bread:entry sb_bread entry
0 262935 brelse:entry brelse entry
0 262935 brelse:entry brelse entry
0 262995 isofs_iget:entry isofs_iget entry
0 262932 isofs_alloc_inode:entry isofs_alloc_inode entry
0 262937 init_once:entry init_once entry
0 262937 init_once:entry init_once entry
0 262937 init_once:entry init_once entry
0 262937 init_once:entry init_once entry
0 262937 init_once:entry init_once entry
0 262937 init_once:entry init_once entry
0 262933 isofs_alloc_inode:return isofs_alloc_inode return
0 262917 isofs_iget5_set:entry isofs_iget5_set entry
0 262918 isofs_iget5_set:return isofs_iget5_set return
0 262934 sb_bread:entry sb_bread entry

Never returns from sb_bread presumably. Now to see how to work kgdb!

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/40#issuecomment-7857051.

[OmegaPhil]

Cheers :)

Sure - should I spam here or somewhere else? I think this is pretty much
what I was aiming to get out of dtrace (although I am somewhat ignorant
of what it can achieve). I am currently levelling up to start diving
into the kernel proper with kgdb, now I have some target functions to
look at. I dont really know C and I'm certainly no kernel programmer -
my target is more to find some crap code and then do a basic patch to
detect the problem and exit out. Locking up mount and then making the
operating system unrestartable without a hardboot is Windows-level
failure, so I thought it would be a good introduction.

On 20/08/12 23:37, dtrace4linux wrote:

Just a note to say I fixed the driver loading issue.

Interested to see how you get on with this issue, and if dtrace helps you.

thanks

On 19 August 2012 22:29, OmegaPhil notifications@github.com wrote:

Works great - heres the output when mount locks up with 100% kernel mode
on trying to mount a presumably bad iso9660 filesystem:

dtrace: script './isofs_tracing.d' matched 96 probes
CPU ID FUNCTION:NAME
0 262919 isofs_mount:entry isofs_mount entry
0 262920 isofs_fill_super:entry isofs_fill_super entry
0 262934 sb_bread:entry sb_bread entry
0 262935 brelse:entry brelse entry
0 262936 brelse:return brelse return
0 262934 sb_bread:entry sb_bread entry
0 262935 brelse:entry brelse entry
0 262935 brelse:entry brelse entry
0 262995 isofs_iget:entry isofs_iget entry
0 262932 isofs_alloc_inode:entry isofs_alloc_inode entry
0 262937 init_once:entry init_once entry
0 262937 init_once:entry init_once entry
0 262937 init_once:entry init_once entry
0 262937 init_once:entry init_once entry
0 262937 init_once:entry init_once entry
0 262937 init_once:entry init_once entry
0 262933 isofs_alloc_inode:return isofs_alloc_inode return
0 262917 isofs_iget5_set:entry isofs_iget5_set entry
0 262918 isofs_iget5_set:return isofs_iget5_set return
0 262934 sb_bread:entry sb_bread entry

Never returns from sb_bread presumably. Now to see how to work kgdb!

—
Reply to this email directly or view it on
GitHubhttps://github.com//issues/40#issuecomment-7857051.

—
Reply to this email directly or view it on GitHub
#40 (comment).