Message-ID: <2bfd10f675844fe4c4a12589a17bc69199a25604.camel@hammerspace.com>
Date:   Tue, 24 Sep 2019 17:58:38 +0000
From:   Trond Myklebust <trondmy@...merspace.com>
To:     "nbowler@...conx.ca" <nbowler@...conx.ca>
CC:     "linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>,
        "keyrings@...r.kernel.org" <keyrings@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: PROBLEM: nfs? crash in Linux 5.3 (possible regression)

On Tue, 2019-09-24 at 13:55 -0400, Nick Bowler wrote:
> On 9/20/19, Nick Bowler <nbowler@...conx.ca> wrote:
> > On 9/20/19, Trond Myklebust <trondmy@...merspace.com> wrote:
> > > On Fri, 2019-09-20 at 14:23 -0400, Nick Bowler wrote:
> > > > Not sure how reproducible this is.  Since I've never seen a
> > > > crash
> > > > like this before it may be a regression compared to, say, Linux
> > > > 4.19
> > > > but I am not certain because this particular machine is brand
> > > > new so
> > > > I don't have experience with older kernels on it...
> > 
> > So it actually seems pretty reliably reproducible, 4 attempts to
> > compile
> > Linux on Linux 5.3 and all four crash the same way, although
> > there's
> > definitely some randomness here...
> > 
> > On the other hand, I cannot reproduce if I install Linux 5.2 so it
> > does
> > seem like a regression in 5.3.  I will see how well bisecting
> > goes...
> 
> Not well I guess?  I'm not sure what it's doing but for some reason
> git
> bisect does not seem to be converging towards any solution.  I run
> for
> several hours before marking 'good' and it only seems to be reducing
> the
> '# of revisions left to test' by a tiny amount, not the ~half like
> I'd expect so bleh...
> 
> Any ideas what could be wrong?  Hints on how to reproduce faster?

As I said, this is a keyring bug. It has nothing whatsoever to do with
NFS, so I have no advice.

> 
> git bisect start
> # bad: [4d856f72c10ecb060868ed10ff1b1453943fc6c8] Linux 5.3
> git bisect bad 4d856f72c10ecb060868ed10ff1b1453943fc6c8
> # good: [0ecfebd2b52404ae0c54a878c872bb93363ada36] Linux 5.2
> git bisect good 0ecfebd2b52404ae0c54a878c872bb93363ada36
> # skip: [c236b6dd48dcf2ae6ed14b9068830eccc3e181e6] Merge tag
> 'keys-request-20190626' of
> git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
> git bisect skip c236b6dd48dcf2ae6ed14b9068830eccc3e181e6
> # skip: [028db3e290f15ac509084c0fc3b9d021f668f877] Revert "Merge tag
> 'keys-acl-20190703' of
> git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs"
> git bisect skip 028db3e290f15ac509084c0fc3b9d021f668f877
> # bad: [002c5f73c508f7df5681bda339831c27f3c1aef4] KVM: x86/mmu:
> Reintroduce fast invalidate/zap for flushing memslot
> git bisect bad 002c5f73c508f7df5681bda339831c27f3c1aef4
> # bad: [d3464ccd105b42f87302572ee1f097e6e0b432c6] Merge tag
> 'dmaengine-fix-5.3' of git://git.infradead.org/users/vkoul/slave-dma
> git bisect bad d3464ccd105b42f87302572ee1f097e6e0b432c6
> # bad: [0445971000375859008414f87e7c72fa0d809cf8] Merge tag
> 'mmc-v5.3-rc7' of
> git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc
> git bisect bad 0445971000375859008414f87e7c72fa0d809cf8
> # bad: [046ddeed0461b5d270470c253cbb321103d048b6] KVM: Check
> preempted_in_kernel for involuntary preemption
> git bisect bad 046ddeed0461b5d270470c253cbb321103d048b6
> # skip: [8f6ccf6159aed1f04c6d179f61f6fb2691261e84] Merge tag
> 'clone3-v5.3' of
> git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
> git bisect skip 8f6ccf6159aed1f04c6d179f61f6fb2691261e84
> # good: [d84f6269ce24eb4c468e246b24fc0fdce34ab6f6] crypto: ccree -
> check that cryptocell reset completed
> git bisect good d84f6269ce24eb4c468e246b24fc0fdce34ab6f6
> # good: [5f92229d184b80712a8b94d098318960171ae749] ASoC: mxs:
> mxs-sgtl5000: don't select unnecessary Platform
> git bisect good 5f92229d184b80712a8b94d098318960171ae749
> # good: [a2928d28643e3c064ff41397281d20c445525032] r8169: use paged
> versions of phylib MDIO access functions
> git bisect good a2928d28643e3c064ff41397281d20c445525032
> # good: [1b2fc358ddfb1b0915922e441182cda7043f5116] perf tools: Add
> missing util.h to pick up 'page_size' variable
> git bisect good 1b2fc358ddfb1b0915922e441182cda7043f5116
> # good: [a011b49f4ed7813777a15da12a426ab939c58f14] net/mlx5e:
> Consider
> XSK in XDP MTU limit calculation
> git bisect good a011b49f4ed7813777a15da12a426ab939c58f14
> # good: [89a237aa84c7047cafba99f5dc81983ed0c40704] staging: kpc2000:
> Use '%llx' for printing 'long long int' type
> git bisect good 89a237aa84c7047cafba99f5dc81983ed0c40704
> # good: [60e8523e2ea18dc0c0cea69d6c1d69a065019062] ocxl: Allow
> contexts to be attached with a NULL mm
> git bisect good 60e8523e2ea18dc0c0cea69d6c1d69a065019062
> # good: [452181936931f0f08923aba5e04e1e9ef58c389f] afs: Trace
> afs_server usage
> git bisect good 452181936931f0f08923aba5e04e1e9ef58c389f
> # good: [78ff751f8e6a9446e9fb26b2bff0b8d3f8974cbd] scsi: mac_scsi:
> Fix
> pseudo DMA implementation, take 2
> git bisect good 78ff751f8e6a9446e9fb26b2bff0b8d3f8974cbd
> # good: [5315f9d40191f98abcd3164e632a8a8f737b1cf0] rtlwifi: remove
> redundant assignment to variable badworden
> git bisect good 5315f9d40191f98abcd3164e632a8a8f737b1cf0
> # good: [65dc5416d4e02d80ce140078c7c1f4e6c8400396] Merge tag
> 'batadv-next-for-davem-20190627v2' of
> git://git.open-mesh.org/linux-merge
> git bisect good 65dc5416d4e02d80ce140078c7c1f4e6c8400396
> # skip: [0248a8be6d21dad72b9ce80a7565cf13c11509d8] Merge tag
> 'gfs2-for-5.3' of
> git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
> git bisect skip 0248a8be6d21dad72b9ce80a7565cf13c11509d8
> # good: [aa0bfcd939c30617385ffa28682c062d78050eba] mm: add
> filemap_fdatawait_range_keep_errors()
> git bisect good aa0bfcd939c30617385ffa28682c062d78050eba
> # good: [15a98fb2fc287bbfe430e854d56dcfc86eae21db] media:
> dvb_frontend: split dvb_frontend_handle_ioctl function
> git bisect good 15a98fb2fc287bbfe430e854d56dcfc86eae21db
> # good: [d17adf7d3f5be74bdfda89ceed7bff3910ffb6d4] regulator:
> max77802: Drop unused includes
> git bisect good d17adf7d3f5be74bdfda89ceed7bff3910ffb6d4
> 
> > > > [  796.050025] BUG: kernel NULL pointer dereference, address:
> > > > 0000000000000014
> > > > [  796.051280] #PF: supervisor read access in kernel mode
> > > > [  796.053063] #PF: error_code(0x0000) - not-present page
> > > > [  796.054636] PGD 0 P4D 0
> > > > [  796.055688] Oops: 0000 [#1] PREEMPT SMP
> > > > [  796.056768] CPU: 2 PID: 190 Comm: kworker/2:2 Tainted:
> > > > G        W
> > > >       5.3.0 #6
> > > > [  796.057953] Hardware name: To Be Filled By O.E.M. To Be
> > > > Filled By
> > > > O.E.M./B450 Gaming-ITX/ac, BIOS P3.30 05/17/2019
> > > > [  796.059329] Workqueue: events key_garbage_collector
> > > > [  796.060623] RIP: 0010:keyring_gc_check_iterator+0x27/0x30
> > > 
> > > That would be the keyring garbage collector, not NFS.
> > > 
> > > Cced keyrings@...r.kernel.org
> > > 
> > > 
> > > > [  796.061845] Code: 44 00 00 48 83 e7 fc b8 01 00 00 00 f6 87
> > > > 80 00
> > > > 00 00 21 75 19 48 8b 57 58 48 39 16 7c 05 48 85 d2 7f 0b 48 8b
> > > > 87 a0
> > > > 00 00 00 <0f> b6 40 14 c3 0f 1f 40 00 48 83 e7 fc e9 27 eb ff
> > > > ff 0f
> > > > 1f
> > > > 80 00
> > > > [  796.064638] RSP: 0018:ffffb40fc0757df8 EFLAGS: 00010282
> > > > [  796.066058] RAX: 0000000000000000 RBX: ffffa14338caed80 RCX:
> > > > ffffb40fc0757e40
> > > > [  796.067531] RDX: ffffa1433ae85558 RSI: ffffb40fc0757e40 RDI:
> > > > ffffa1433ae85500
> > > > [  796.069014] RBP: ffffb40fc0757e40 R08: 0000000000000000 R09:
> > > > 000000000000000f
> > > > [  796.070513] R10: 8080808080808080 R11: 0000000000000001 R12:
> > > > ffffffffa4cd6180
> > > > [  796.072025] R13: ffffa14338caee10 R14: ffffa14338caedf0 R15:
> > > > ffffa1433ffeff00
> > > > [  796.073567] FS:  0000000000000000(0000)
> > > > GS:ffffa14340480000(0000)
> > > > knlGS:0000000000000000
> > > > [  796.075171] CS:  0010 DS: 0000 ES: 0000 CR0:
> > > > 0000000080050033
> > > > [  796.076785] CR2: 0000000000000014 CR3: 0000000747ce6000 CR4:
> > > > 00000000003406e0
> > > > [  796.078445] Call Trace:
> > > > [  796.080091]  assoc_array_subtree_iterate+0x55/0x100
> > > > [  796.081770]  keyring_gc+0x3f/0x80
> > > > [  796.083447]  key_garbage_collector+0x330/0x3d0
> > > > [  796.085155]  process_one_work+0x1cb/0x320
> > > > [  796.086869]  worker_thread+0x28/0x3c0
> > > > [  796.088603]  ? process_one_work+0x320/0x320
> > > > [  796.090335]  kthread+0x106/0x120
> > > > [  796.092053]  ? kthread_create_on_node+0x40/0x40
> > > > [  796.093810]  ret_from_fork+0x1f/0x30
> > > > [  796.095569] Modules linked in: sha1_ssse3 sha1_generic cbc
> > > > cts
> > > > rpcsec_gss_krb5 auth_rpcgss nfsv4 nfs lockd grace ext4 crc16
> > > > mbcache
> > > > jbd2 iwlmvm mac80211 libarc4 amdgpu iwlwifi
> > > > snd_hda_codec_realtek
> > > > snd_hda_codec_generic kvm_amd gpu_sched kvm snd_hda_codec_hdmi
> > > > drm_kms_helper irqbypass k10temp syscopyarea sysfillrect
> > > > sysimgblt
> > > > fb_sys_fops video ttm cfg80211 snd_hda_intel snd_hda_codec drm
> > > > snd_hwdep rfkill snd_hda_core backlight snd_pcm evdev snd_timer
> > > > snd
> > > > soundcore efivarfs dm_crypt hid_generic igb hwmon i2c_algo_bit
> > > > sr_mod
> > > > cdrom sunrpc dm_mod
> > > > [  796.104033] CR2: 0000000000000014
> > > > [  796.106304] ---[ end trace 695aee10f9202347 ]---
> > > > [  796.108585] RIP: 0010:keyring_gc_check_iterator+0x27/0x30
> > > > [  796.110894] Code: 44 00 00 48 83 e7 fc b8 01 00 00 00 f6 87
> > > > 80 00
> > > > 00 00 21 75 19 48 8b 57 58 48 39 16 7c 05 48 85 d2 7f 0b 48 8b
> > > > 87 a0
> > > > 00 00 00 <0f> b6 40 14 c3 0f 1f 40 00 48 83 e7 fc e9 27 eb ff
> > > > ff 0f
> > > > 1f
> > > > 80 00
> > > > [  796.115773] RSP: 0018:ffffb40fc0757df8 EFLAGS: 00010282
> > > > [  796.118209] RAX: 0000000000000000 RBX: ffffa14338caed80 RCX:
> > > > ffffb40fc0757e40
> > > > [  796.120683] RDX: ffffa1433ae85558 RSI: ffffb40fc0757e40 RDI:
> > > > ffffa1433ae85500
> > > > [  796.123176] RBP: ffffb40fc0757e40 R08: 0000000000000000 R09:
> > > > 000000000000000f
> > > > [  796.125668] R10: 8080808080808080 R11: 0000000000000001 R12:
> > > > ffffffffa4cd6180
> > > > [  796.128104] R13: ffffa14338caee10 R14: ffffa14338caedf0 R15:
> > > > ffffa1433ffeff00
> > > > [  796.130493] FS:  0000000000000000(0000)
> > > > GS:ffffa14340480000(0000)
> > > > knlGS:0000000000000000
> > > > [  796.132923] CS:  0010 DS: 0000 ES: 0000 CR0:
> > > > 0000000080050033
> > > > [  796.135266] CR2: 0000000000000014 CR3: 0000000747ce6000 CR4:
> > > > 00000000003406e0
-- 
Trond Myklebust
CTO, Hammerspace Inc
4300 El Camino Real, Suite 105
Los Altos, CA 94022
www.hammer.space

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