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Re: Kernel oops+crash on repeated auditd restarts



Yes, i know that patch. It made it into kernel 3.2.2. I tested it successfully (oops in 3.2.1, no oops in 3.2.9), but this oops i'm seeing is also in 3.2.9.

I monitored changelogs since 3.2.1 to 3.2.12 but there were no fixes either in audit subsystem or in fsnotify. I'll try to reproduce in latest 3.2.13 and repost the oops, but i'm 99% confident it will be the same.

Sadly nobody except you seems to pay attention to this problem, probably because it requires special conditions to reproduce (really, who starts and stops auditd every 5 seconds on a production server?). We only ran into it because one of our servers would randomly oops and then freeze about each month after stopping and then starting

auditd

every morning (and the stop-start sequence was needed to workaround a bug somewhere that would hang a

gzip

running on a file outside a watched folder).

Anyway, as a last note, i have a feeling that the oops is not exactly random, there is a pattern, just that i haven't figured it out completely yet.

Will keep you

uptodate

with the things i find out.

V.

On Mar 29, 2012 4:14 AM, "Eric Paris" <eparis redhat com> wrote:
That patch fixes a BUG() .  The report has a NULL ptr deref and some
apparent list correuption....  Sadly they aren't the same....

On Wed, 2012-03-28 at 15:42 -0700, Peter Moody wrote:
> fyi: this patch [1] seems to fix the issue for me. The explanation in
> the subject would reliably oops my machine.
>
> [1] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=fed474857efbed79cd390d0aee224231ca718f63
>
> On Wed, Mar 28, 2012 at 1:51 PM, Peter Moody <pmoody google com> wrote:
> > Are you still able to reliably reproduce this oops? I'm trying to
> > track this down because this bug (or a very similar bug) is causing
> > some significant headaches here at work, but I haven't had a lot of
> > luck. I'm using usermode linux, though, so that might be interfering
> > with things.
> >
> > On Mon, Mar 5, 2012 at 12:35 AM, Valentin Avram <aval13 gmail com> wrote:
> >> Finally i found some time and spare server to retest the oops and list_add
> >> corruptions i was getting with the 3.x kernels and auditd 2.1.3.
> >>
> >> I tested now with gentoo's latest stable 3.2.1-gentoo-r2 and kernel.org's
> >> 3.2.9.
> >>
> >> Both get the oops/BUG in the same way and after that, they keep pouring
> >> list_add corruptions with audit_prune_tre(truncated?) and auditctl as comms.
> >>
> >> Since this is not about Gentoo's kernel only, i'll post here the oops in
> >> 3.2.9 and also attach some list_add corruptions.
> >>
> >> 3.2.9 BUG:
> >>
> >> kernel: [  301.240011] BUG: unable to handle kernel NULL pointer dereference
> >> at   (null)
> >> kernel: [  301.240305] IP: [<c1238dd0>] __list_del_entry+0x20/0xe0
> >> kernel: [  301.240481] *pdpt = 0000000000000000 *pde = f000ddc8f000ddc8
> >> kernel: [  301.240698] Oops: 0000 [#1] SMP
> >> kernel: [  301.240910]
> >> kernel: [  301.241030] Pid: 642, comm: fsnotify_mark Not tainted
> >> 3.2.9-drbd-version3 #1 Dell Inc. PowerEdge 2950/0CX396
> >> kernel: [  301.241370] EIP: 0060:[<c1238dd0>] EFLAGS: 00010287 CPU: 6
> >> kernel: [  301.241498] EIP is at __list_del_entry+0x20/0xe0
> >> kernel: [  301.241623] EAX: f4fae544 EBX: f47cffa4 ECX: ffffffff EDX:
> >> 00000000
> >> kernel: [  301.241751] ESI: f4fae544 EDI: f4fae508 EBP: f47cff7c ESP:
> >> f47cff64
> >> kernel: [  301.241879]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
> >> kernel: [  301.242005] Process fsnotify_mark (pid: 642, ti=f47ce000
> >> task=f4f47c00 task.ti=f47ce000)
> >> kernel: [  301.242207] Stack:
> >> kernel: [  301.242327]  c10813c0 f47cffa4 f4f47c00 f4e70888 f47cff7c
> >> f47cffa4 f47cffb8 c10f6976
> >> kernel: [  301.242882]  ffffffc3 f4f47c00 f4f47c00 00000000 f4f47c00
> >> c10530c0 f47cff9c f47cff9c
> >> kernel: [  301.243438]  f4fae544 f4fae544 f4c47f58 00000000 c10f68f0
> >> f47cffe4 c1052834 00000000
> >> kernel: [  301.243995] Call Trace:
> >> kernel: [  301.244119]  [<c10813c0>] ? rcu_check_callbacks+0x110/0x110
> >> kernel: [  301.244248]  [<c10f6976>] fsnotify_mark_destroy+0x86/0x120
> >> kernel: [  301.244377]  [<c10530c0>] ? abort_exclusive_wait+0x80/0x80
> >> kernel: [  301.244504]  [<c10f68f0>] ? fsnotify_put_mark+0x30/0x30
> >> kernel: [  301.244631]  [<c1052834>] kthread+0x74/0x80
> >> kernel: [  301.244756]  [<c10527c0>] ? kthread_flush_work_fn+0x10/0x10
> >> kernel: [  301.244885]  [<c1582ab6>] kernel_thread_helper+0x6/0xd
> >> kernel: [  301.245011] Code: 55 f4 8b 45 f8 e9 75 ff ff ff 90 55 89 e5 53 83
> >> ec 14 8b 08 8b 50 04 81 f9 00 01 10 00 74 24 81 fa 00 02 20 00 0f 84 8e 00
> >> 00 00 <8b> 1a 39 d8 75 62 8b 59 04 39 d8 75 35 89 51 04 89 0a 83 c4 14
> >> kernel: [  301.248195] EIP: [<c1238dd0>] __list_del_entry+0x20/0xe0 SS:ESP
> >> 0068:f47cff64
> >> kernel: [  301.248414] CR2: 0000000000000000
> >> kernel: [  301.248538] ---[ end trace 15082dbfb353f84c ]---
> >>
> >> The kernel was compiled with the following DEBUG support (the bolded one
> >> were requested by Gentoo's Dev:
> >> CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC=y
> >> CONFIG_SLUB_DEBUG=y
> >> CONFIG_HAVE_DMA_API_DEBUG=y
> >> CONFIG_X86_DEBUGCTLMSR=y
> >> CONFIG_PNP_DEBUG_MESSAGES=y
> >> CONFIG_AIC94XX_DEBUG=y
> >> CONFIG_USB_DEBUG=y
> >> CONFIG_DEBUG_KERNEL=y
> >> CONFIG_SCHED_DEBUG=y
> >> CONFIG_DEBUG_RT_MUTEXES=y
> >> CONFIG_DEBUG_PI_LIST=y
> >> CONFIG_DEBUG_BUGVERBOSE=y
> >> CONFIG_DEBUG_INFO=y
> >> CONFIG_DEBUG_MEMORY_INIT=y
> >> CONFIG_DEBUG_LIST=y
> >> CONFIG_DEBUG_STACKOVERFLOW=y
> >> CONFIG_DEBUG_RODATA=y
> >> CONFIG_DEBUG_RODATA_TEST=y
> >>
> >> I attached the kernel config i used for 3.2.9 to generate this oops and
> >> warnings.
> >>
> >> From the list_add warnings that come after, out of 805 warnings i processed,
> >> after masking with XXXXX the PID and next= values that kept changing in
> >> every one, i got 26 types of MD5. I also attached the files relevant as an
> >> archive to this email.
> >>
> >> The Gentoo bug i opened is sleeping, it seems nobody has the time to at
> >> least test to confirm or not the problems i'm seeing (or everybody's
> >> thinking that nobody would restart auditd so often, so the bug it's not that
> >> serious).
> >>
> >>
> >> Thank you for your time.
> >>
> >> On Wed, Feb 8, 2012 at 6:11 PM, Valentin Avram <aval13 gmail com> wrote:
> >>
> >>
> >> --
> >> Linux-audit mailing list
> >> Linux-audit redhat com
> >> https://www.redhat.com/mailman/listinfo/linux-audit
> >
> >
> >
> > --
> > Peter Moody      Google    1.650.253.7306
> > Security Engineer  pgp:0xC3410038
>
>
>



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