This works for me. Thanks, Marcelo! Cheers, peter
On Fri, Apr 20, 2012 at 7:14 PM, Marcelo Cerri <[email protected]> wrote: > > I took a look at the source code and made some tests. It seems to be a > problem with the reference count of the fsnotify_mark structure. > > This error occurs because the fsnotify_mark_destroy function > (which runs in a separated kthread) is trying to iterate through a mark > that is already freed. > > Looking at the fsnotify_destroy_mark function (not confuse with > fsnotify_mark_destroy), which adds a mark to destroy_list to be freed > later by fsnotify_mark_destroy, I noticed that it does not increment > the reference count for the reference added to the destroy_list and > usually the callers dispose the references they held after calling > fsnotify_destroy_mark. > > The patch below increments the reference count of a mark when it is > added to the destroy list. It seems to solve the issue and it doesn't > seem to cause any memory leak. Please, can you make some tests in your > environments and let me know if there is any problem with this patch. > > Regarding the synchronize_scru call, I don't think it's causing this > error. Probably it just make it more frequently because it forces all > the cpus to schedule, giving the chance to someone else to free the > mark. > > --- > fs/notify/mark.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/notify/mark.c b/fs/notify/mark.c > index f104d56..2985fff 100644 > --- a/fs/notify/mark.c > +++ b/fs/notify/mark.c > @@ -150,6 +150,7 @@ void fsnotify_destroy_mark(struct fsnotify_mark > *mark) spin_unlock(&group->mark_lock); > spin_unlock(&mark->lock); > > + fsnotify_get_mark(mark); > spin_lock(&destroy_lock); > list_add(&mark->destroy_list, &destroy_list); > spin_unlock(&destroy_lock); > -- > 1.7.9.4 > > > On Tue, 17 Apr 2012 14:54:29 -0700 > Peter Moody <[email protected]> wrote: > >> 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 <[email protected]> >> wrote: >> > and my config.gz >> > >> > On Tue, Apr 17, 2012 at 10:56 AM, Peter Moody <[email protected]> >> > 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 <[email protected]> >> >> 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 <[email protected]> >> >>>> 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 >> >>>> > <[email protected]> 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" <[email protected]> >> >>>> >> 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 >> >>>> >>> > <[email protected]> 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 >> >>>> >>> > > <[email protected]> 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 >> >>>> >>> > >> <[email protected]> wrote: >> >>>> >>> > >> >> >>>> >>> > >> >> >>>> >>> > >> -- >> >>>> >>> > >> Linux-audit mailing list >> >>>> >>> > >> [email protected] >> >>>> >>> > >> 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 >> >> >> > -- Peter Moody Google 1.650.253.7306 Security Engineer pgp:0xC3410038 -- Linux-audit mailing list [email protected] https://www.redhat.com/mailman/listinfo/linux-audit
