Re: Kernel oops+crash on repeated auditd restarts

(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