[lttng-dev] lttng create call trace on kernel 4.19

Jonathan Rajotte-Julien jonathan.rajotte-julien at efficios.com
Thu Oct 18 12:10:34 EDT 2018 

Hi Dengke,

The fix for the kernel was pulled into linux-master KH[1]

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9c0be3f6b5d776dfe3ed249862c244a4486414dc

The corresponding changes for lttng-modules were merged and backported (2.9, 2.10, 2.11). [2]

https://github.com/lttng/lttng-modules/commit/c1b0a62512c0dad3c79f3eb29ed29d3a702f2274

Again thanks again for reporting this issue.

Cheers

On Fri, Oct 12, 2018 at 12:21:18PM -0400, Jonathan Rajotte-Julien wrote:
> Hi Dengke,
> 
> We were able to reproduce it. This is not related to yocto and seems to be
> related to a change introduced in the 4.19 kernel.
> 
> If you are not interested in kernel tracing you can pass the --no-kernel flag to
> lttng-sessiond to prevent the loading of the kernel modules.
> 
> We are looking into the root problem and possible fix on either the kernel side
> or ours.
> 
> Thanks for reporting the issue. We will keep you updated.
> 
> Cheers
> 
> On Fri, Oct 12, 2018 at 11:10:09AM -0400, Mathieu Desnoyers wrote:
> > ----- On Oct 11, 2018, at 9:21 PM, Dengke Du dengke.du at windriver.com wrote:
> > 
> > > On 2018年10月11日 21:22, Jonathan Rajotte-Julien wrote:
> > >> Hi,
> > >>
> > >> On Thu, Oct 11, 2018 at 02:00:11PM +0800, Dengke Du wrote:
> > >>> Hi all
> > >>>
> > >>> When I create a local trace session, meeting a call trace:
> > >>>
> > >>> uname -a:
> > >>>
> > >>> Linux qemux86-64 4.19.0-rc7-yoctodev-standard #1 SMP PREEMPT Thu Oct 11
> > >>> 03:32:48 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
> > >> Which yocto branch, recipes(for kernel, lttng-tools, lttng-modules) and target?
> > >>
> > >> Which version of lttng-modules are you using?
> > 
> > Please answer the questions above as well.
> > 
> > Thanks,
> > 
> > Mathieu
> > 
> > 
> > >>
> > >> Any modification to the kernel?
> > > 
> > > Yocto: master branch
> > > Kernel: linux-yocto-dev
> > > 
> > > phenomenon 1:
> > >     linux-yocto was ok (v4.18)
> > > phenomenon 2:
> > >     linux-yocto-dev was not ok (v4.19)
> > > 
> > > Maybe some kernel commit breaks it.
> > > 
> > >>
> > >>> lttng create trace_session --live -U net://127.0.0.1
> > >>>
> > >>> ----------------------------------------------------------------------------------------------------------
> > >>>
> > >>> [  222.390601] lttng_kretprobes: loading out-of-tree module taints kernel.
> > >>> [  223.550725] BUG: unable to handle kernel paging request at
> > >>> 0000111400001158
> > >>> [  223.551661] PGD 0 P4D 0
> > >>> [  223.552476] Oops: 0000 [#1] PREEMPT SMP PTI
> > >>> [  223.553170] CPU: 0 PID: 500 Comm: modprobe Tainted: G O
> > >>> 4.19.0-rc7-yoctodev-standard #1
> > >>> [  223.553892] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> > >>> rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
> > >>> [  223.556619] RIP: 0010:lttng_tracepoint_notify+0x16e/0x200 [lttng_tracer]
> > >>> [  223.557751] Code: eb bd 48 39 c1 0f 85 a3 00 00 00 49 8b 55 10 41 83 c4
> > >>> 01 44 39 a2 8c 02 00 00 76 a3 48 8b 92 90 02 00 00 49 63 c4 48 8b 0c c2 <4c>
> > >>> 8b 31 48 89 4d d0 4c 89 f7 e8 90
> > >>> [  223.559769] RSP: 0000:ffffa39a00373bc0 EFLAGS: 00000206
> > >>> [  223.560303] RAX: 0000000000000000 RBX: ffff9b3dd45a83a0 RCX:
> > >>> 0000111400001158
> > >>> [  223.560959] RDX: ffffffffc01b9048 RSI: 0000000000000001 RDI:
> > >>> ffffffffc02f1100
> > >>> [  223.561579] RBP: ffffa39a00373bf0 R08: 0000000000000064 R09:
> > >>> ffff9b3ddec01600
> > >>> [  223.562388] R10: ffffffffc0287411 R11: ffffffff98dc9660 R12:
> > >>> 0000000000000000
> > >>> [  223.563008] R13: ffff9b3dd45a83a0 R14: ffffa39a00373e78 R15:
> > >>> 0000000000000002
> > >>> [  223.563905] FS:  00007fb049015740(0000) GS:ffff9b3ddf200000(0000)
> > >>> knlGS:0000000000000000
> > >>> [  223.564941] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > >>> [  223.565501] CR2: 0000111400001158 CR3: 0000000014586000 CR4:
> > >>> 00000000000006f0
> > >>> [  223.566450] Call Trace:
> > >>> [  223.568367]  ? lttng_kernel_tracepoint_add+0x50/0xc0 [lttng_tracer]
> > >>> [  223.569932]  register_tracepoint_module_notifier+0x57/0x80
> > >>> [  223.571309]  ? 0xffffffffc0309000
> > >>> [  223.572187]  lttng_tracepoint_init+0x45/0xbf9 [lttng_tracer]
> > >>> [  223.573125]  lttng_events_init+0x40/0x1cc [lttng_tracer]
> > >>> [  223.573820]  ? 0xffffffffc0309000
> > >>> [  223.574237]  do_one_initcall+0x53/0x1fe
> > >>> [  223.574682]  ? __vunmap+0x8e/0xc0
> > >>> [  223.575196]  ? kmem_cache_alloc_trace+0xfc/0x1d0
> > >>> [  223.575684]  ? do_init_module+0x27/0x210
> > >>> [  223.576285]  do_init_module+0x60/0x210
> > >>> [  223.576702]  load_module+0x2406/0x2570
> > >>> [  223.577140]  ? vfs_read+0x115/0x140
> > >>> [  223.577611]  ? vfs_read+0x115/0x140
> > >>> [  223.578034]  __se_sys_finit_module+0xc3/0xe0
> > >>> [  223.578581]  ? __se_sys_finit_module+0xc3/0xe0
> > >>> [  223.579135]  __x64_sys_finit_module+0x1a/0x20
> > >>> [  223.579627]  do_syscall_64+0x4d/0xf0
> > >>> [  223.580071]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > >>> [  223.580837] RIP: 0033:0x7fb049107569
> > >>> [  223.581286] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48
> > >>> 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48>
> > >>> 3d 01 f0 ff ff 73 01 c3 48 8b 08
> > >>> [  223.583210] RSP: 002b:00007ffc80620498 EFLAGS: 00000246 ORIG_RAX:
> > >>> 0000000000000139
> > >>> [  223.583958] RAX: ffffffffffffffda RBX: 000055931b680b70 RCX:
> > >>> 00007fb049107569
> > >>> [  223.584677] RDX: 0000000000000000 RSI: 000055931b67734e RDI:
> > >>> 000000000000000a
> > >>> [  223.585372] RBP: 0000000000000000 R08: 0000000000000000 R09:
> > >>> 000055931b680b70
> > >>> [  223.586008] R10: 000000000000000a R11: 0000000000000246 R12:
> > >>> 000055931b67734e
> > >>> [  223.586696] R13: 0000000000040000 R14: 0000000000000000 R15:
> > >>> 0000000000000000
> > >>> [  223.587620] Modules linked in: lttng_tracer(O+) lttng_statedump(O)
> > >>> lttng_ftrace(O) lttng_kprobes(O) lttng_clock(O) lttng_lib_ring_buffer(O)
> > >>> lttng_kretprobes(O) deflate twofish_geneb
> > >>> [  223.597615] CR2: 0000111400001158
> > >>> [  223.614673] ---[ end trace 514884c3611a01af ]---
> > >>> [  223.615793] RIP: 0010:lttng_tracepoint_notify+0x16e/0x200 [lttng_tracer]
> > >>> [  223.616604] Code: eb bd 48 39 c1 0f 85 a3 00 00 00 49 8b 55 10 41 83 c4
> > >>> 01 44 39 a2 8c 02 00 00 76 a3 48 8b 92 90 02 00 00 49 63 c4 48 8b 0c c2 <4c>
> > >>> 8b 31 48 89 4d d0 4c 89 f7 e8 90
> > >>> [  223.624684] RSP: 0000:ffffa39a00373bc0 EFLAGS: 00000206
> > >>> [  223.625177] RAX: 0000000000000000 RBX: ffff9b3dd45a83a0 RCX:
> > >>> 0000111400001158
> > >>> [  223.626102] RDX: ffffffffc01b9048 RSI: 0000000000000001 RDI:
> > >>> ffffffffc02f1100
> > >>> [  223.632541] RBP: ffffa39a00373bf0 R08: 0000000000000064 R09:
> > >>> ffff9b3ddec01600
> > >>> [  223.633110] R10: ffffffffc0287411 R11: ffffffff98dc9660 R12:
> > >>> 0000000000000000
> > >>> [  223.637690] R13: ffff9b3dd45a83a0 R14: ffffa39a00373e78 R15:
> > >>> 0000000000000002
> > >>> [  223.641583] FS:  00007fb049015740(0000) GS:ffff9b3ddf200000(0000)
> > >>> knlGS:0000000000000000
> > >>> [  223.642238] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > >>> [  223.642906] CR2: 00007f6eae3e4b58 CR3: 0000000014586000 CR4:
> > >>> 00000000000006f0
> > >>> 2018 Oct 11 05:37:07 qemux86-64 [  223.550725] BUG: unable to handle kernel
> > >>> paging request at 0000111400001158
> > >>> 2018 Oct 11 05:37:07 qemux86-64 BUG: unable to handle kernel paging request
> > >>> at 0000111400001158
> > >>>
> > >>> ----------------------------------------------------------------------------------------------------------
> > >>>
> > >>> When I type that command again:
> > >>>
> > >>> ----------------------------------------------------------------------------------------------------------
> > >>>
> > >>> Spawning a session daemon
> > >>> Error: Session daemon terminated with an error (exit status: 1)
> > >>> Error: Problem occurred while launching session daemon
> > >>> (/usr/bin/lttng-sessiond)
> > >>> Error: Command error
> > >>>
> > >>> ----------------------------------------------------------------------------------------------------------
> > >>>
> > >>>
> > >>> _______________________________________________
> > >>> lttng-dev mailing list
> > >>> lttng-dev at lists.lttng.org
> > >>> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
> > > 
> > > _______________________________________________
> > > lttng-dev mailing list
> > > lttng-dev at lists.lttng.org
> > > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
> > 
> > -- 
> > Mathieu Desnoyers
> > EfficiOS Inc.
> > http://www.efficios.com
> 
> -- 
> Jonathan Rajotte-Julien
> EfficiOS
> _______________________________________________
> lttng-dev mailing list
> lttng-dev at lists.lttng.org
> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev

-- 
Jonathan Rajotte-Julien
EfficiOS

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