Re: Kernel oops+crash on repeated auditd restarts

Last thing. moving synchronize_srcu(&fsnotify_mark_srcu) out of the for(;;) loop in fs/notify/mark.c appears to solve the stability issues for me. I don't know enough about kernel internals to determine if this is doing lots of other bad things to my system or not. Cheers, peter On Tue, Apr 17, 2012 at 11:24 AM, Peter Moody <pmoody(a)google.com&gt; wrote: > and my config.gz > > On Tue, Apr 17, 2012 at 10:56 AM, Peter Moody <pmoody(a)google.com&gt; > wrote: >> Here's a trace with debugging turned way up plus a few extra >> printk's added to fs/notify/mark.c. I'm looping through >> private_destroy_list before and after the call to synchronize_srcu. >> >> I can reproduce this reliably with kvm with 2 virtual processors: >> Linux desktop 3.4.0-rc3-oops1+ #1 SMP Tue Apr 17 09:59:44 PDT 2012 >> x86_64 GNU/Linux >> >> Cheers, >> peter >> >> On Thu, Apr 5, 2012 at 2:07 PM, Eric Paris <eparis(a)redhat.com&gt; >> wrote: >>> please please please keep on list.  Everything you say might help >>> track it down! >>> >>> On Thu, 2012-04-05 at 14:03 -0700, Peter Moody wrote: >>>> (please let me know if I should take this off-list) >>>> >>>> One other thing (again, maybe already known), but this seems to >>>> be exacerbated by SMP. On my machine, I can't reproduce the >>>> crash if I booth with maxcpus=1. >>>> >>>> Still hunting. >>>> >>>> Cheers, >>>> peter >>>> >>>> On Tue, Apr 3, 2012 at 9:15 AM, Peter Moody <pmoody(a)google.com&gt; >>>> wrote: >>>> > This may already be known, but the issue seems to be limited >>>> > to watch rules. With any watch rules, I can reliably crash my >>>> > machine while freeing a watch rule after only >>>> > starting/stopping auditd a few times. With no watch rules, I >>>> > have no issues. >>>> > >>>> > Cheers, >>>> > peter >>>> > >>>> > On Wed, Mar 28, 2012 at 11:44 PM, Valentin Avram >>>> > <aval13(a)gmail.com&gt; wrote: >>>> >> 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(a)redhat.com&gt; >>>> >> 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... >>>> >>> > >>>> >>> > On Wed, Mar 28, 2012 at 1:51 PM, Peter Moody >>>> >>> > <pmoody(a)google.com&gt; 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(a)gmail.com&gt; 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(a)gmail.com&gt; wrote: >>>> >>> > >> >>>> >>> > >> >>>> >>> > >> -- >>>> >>> > >> Linux-audit mailing list >>>> >>> > >> Linux-audit(a)redhat.com >>>> >>> > >> https://www.redhat.com/mailman/listinfo/linux-audit >>>> >>> > > >>>> >>> > > >>>> >>> > > >>>> >>> > > -- >>>> >>> > > Peter Moody      Google    1.650.253.7306 >>>> >>> > > Security Engineer  pgp:0xC3410038 >>>> >>> > >>>> >>> > >>>> >>> > >>>> >>> >>>> >>> >>>> >> >>>> > >>>> > >>>> > >>>> > -- >>>> > Peter Moody      Google    1.650.253.7306 >>>> > Security Engineer  pgp:0xC3410038 >>>> >>>> >>>> >>> >>> >> >> >> >> -- >> Peter Moody      Google    1.650.253.7306 >> Security Engineer  pgp:0xC3410038 > > > > -- > Peter Moody      Google    1.650.253.7306 > Security Engineer  pgp:0xC3410038