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Bug#682007: [squeeze-backports] NULL pointer dereference in __fscache_read_or_alloc_pages

Raoul Bhatia [IPAX] <r.bhatia@ipax.at> 2013-01-29 11:01:

On 2012-10-12 20:52, Brian Kroth wrote:

Brian Paul Kroth <bpkroth@gmail.com> 2012-10-11 14:06:

Jonathan Nieder <jrnieder@gmail.com> 2012-10-01 01:25:

<snip/>

Once again very sorry for the delay :(
I forgot to disable the DEBUG_INFO and kept filling up my build VMs disk during compile. Then realized I had grabbed the 3.7 rc code, which these patches don't apply against. "git checkout remotes/stable/linux-3.2.y" (results in head c74a5e1fe4d0672936c8fb63d7484dfeaa30669c and 3.2.28), seemed to fix that. 
<snip/>
Anyways, I just started running that on a machine, so I'll let you know if I noticed anything there first before I think about pushing it to further places. 

Thanks,
Brian
Got another panic using this kernel/set of patches. The dump is attached. 

Let me know if you need anything else.


Hi!


Hello!


Has there been any progress regarding this issue?


Not really.  At least not that I'm aware of.


Brian, are you right now using the fsc facility or not?


Yes, with 54 mounts each on about 100 hosts.


If yes, which patches / configure options are you currently using
and how often do you see kernel panics?


Currently we're running this kernel most places:
ii linux-image-3.2.0-0.bpo.2-amd64 3.2.20-1~bpo60+1 Linux 3.2 for 64-bit PCs

With a few hosts gradually moving over to this:
ii linux-image-3.2.0-0.bpo.4-amd64 3.2.35-2~bpo60+1 Linux 3.2 for 64-bit PCs

And one host running 3.2.28 with the set of patches from here:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=682007#47
We've seen the panic on all of those kernels. Since it's fairly recent, I've attached another dump from the bpo.4 3.2.35 kernel's panic.
Frequency and cause is a little difficult to tease out precisely. These are lab machines and the workload may vary quite substantially based on what classes and compute jobs (eg: from condor) happen to be running on them at any given time.
Recently (as of the students returning a week and a half ago) we've seen this on 6 machines.
Past I see 37 other events in the last 90 days (our log rotation period). Usually their clustered together, so probably tied to a particular job's workload. Unfortunately, those jobs are usually gone by the time I see it. 


Are there any workarounds to this issue besides disabling fsc?


Not that I'm aware of.

Let me know if you need anything else.

Thanks,
Brian

Jan 19 02:08:44 tux-116 [120882.927408] BUG: unable to handle kernel 
Jan 19 02:08:44 tux-116 NULL pointer dereference
Jan 19 02:08:44 tux-116 at 0000000000000040
Jan 19 02:08:44 tux-116 [120882.927421] IP:
Jan 19 02:08:44 tux-116 [<ffffffffa103c5f7>] __fscache_read_or_alloc_pages+0x194/0x262 [fscache]
Jan 19 02:08:44 tux-116 [120882.927432] PGD 22120c067 
Jan 19 02:08:44 tux-116 PUD 22157d067 
Jan 19 02:08:44 tux-116 PMD 0 
Jan 19 02:08:44 tux-116 
Jan 19 02:08:44 tux-116 [120882.927440] Oops: 0000 [#1] 
Jan 19 02:08:44 tux-116 SMP 
Jan 19 02:08:44 tux-116 
Jan 19 02:08:44 tux-116 [120882.927446] CPU 0 
Jan 19 02:08:44 tux-116 
Jan 19 02:08:44 tux-116 [120882.927449] Modules linked in:
Jan 19 02:08:44 tux-116 btrfs
Jan 19 02:08:44 tux-116 zlib_deflate
Jan 19 02:08:44 tux-116 libcrc32c
Jan 19 02:08:44 tux-116 ufs
Jan 19 02:08:44 tux-116 qnx4
Jan 19 02:08:44 tux-116 hfsplus
Jan 19 02:08:44 tux-116 hfs
Jan 19 02:08:44 tux-116 minix
Jan 19 02:08:44 tux-116 ntfs
Jan 19 02:08:44 tux-116 vfat
Jan 19 02:08:44 tux-116 msdos
Jan 19 02:08:44 tux-116 fat
Jan 19 02:08:44 tux-116 jfs
Jan 19 02:08:44 tux-116 xfs
Jan 19 02:08:44 tux-116 reiserfs
Jan 19 02:08:44 tux-116 ext2
Jan 19 02:08:44 tux-116 cpufreq_userspace
Jan 19 02:08:44 tux-116 cpufreq_powersave
Jan 19 02:08:44 tux-116 cpufreq_conservative
Jan 19 02:08:44 tux-116 cpufreq_stats
Jan 19 02:08:44 tux-116 autofs4
Jan 19 02:08:44 tux-116 cachefiles
Jan 19 02:08:44 tux-116 binfmt_misc
Jan 19 02:08:44 tux-116 kvm_intel
Jan 19 02:08:44 tux-116 kvm
Jan 19 02:08:44 tux-116 nfsd
Jan 19 02:08:44 tux-116 nfs
Jan 19 02:08:44 tux-116 lockd
Jan 19 02:08:44 tux-116 fscache
Jan 19 02:08:44 tux-116 auth_rpcgss
Jan 19 02:08:44 tux-116 nfs_acl
Jan 19 02:08:44 tux-116 sunrpc
Jan 19 02:08:44 tux-116 netconsole
Jan 19 02:08:44 tux-116 configfs
Jan 19 02:08:44 tux-116 ext3
Jan 19 02:08:44 tux-116 jbd
Jan 19 02:08:44 tux-116 dm_crypt
Jan 19 02:08:44 tux-116 sbs
Jan 19 02:08:44 tux-116 power_supply
Jan 19 02:08:44 tux-116 sbshc
Jan 19 02:08:44 tux-116 adt7475
Jan 19 02:08:44 tux-116 hwmon_vid
Jan 19 02:08:44 tux-116 ipmi_watchdog
Jan 19 02:08:44 tux-116 ipmi_devintf
Jan 19 02:08:44 tux-116 ipmi_si
Jan 19 02:08:44 tux-116 ipmi_msghandler
Jan 19 02:08:44 tux-116 fuse
Jan 19 02:08:44 tux-116 uhci_hcd
Jan 19 02:08:44 tux-116 ohci_hcd
Jan 19 02:08:44 tux-116 snd_hda_codec_realtek
Jan 19 02:08:44 tux-116 snd_hda_intel
Jan 19 02:08:44 tux-116 snd_hda_codec
Jan 19 02:08:44 tux-116 snd_hwdep
Jan 19 02:08:44 tux-116 snd_pcm_oss
Jan 19 02:08:44 tux-116 snd_mixer_oss
Jan 19 02:08:44 tux-116 tpm_infineon
Jan 19 02:08:44 tux-116 snd_pcm
Jan 19 02:08:44 tux-116 nvidia(P)
Jan 19 02:08:44 tux-116 snd_seq_midi
Jan 19 02:08:44 tux-116 acpi_cpufreq
Jan 19 02:08:44 tux-116 mperf
Jan 19 02:08:44 tux-116 snd_rawmidi
Jan 19 02:08:44 tux-116 snd_seq_midi_event
Jan 19 02:08:44 tux-116 snd_seq
Jan 19 02:08:44 tux-116 snd_timer
Jan 19 02:08:44 tux-116 snd_seq_device
Jan 19 02:08:44 tux-116 hp_wmi
Jan 19 02:08:44 tux-116 sparse_keymap
Jan 19 02:08:44 tux-116 rfkill
Jan 19 02:08:44 tux-116 i2c_i801
Jan 19 02:08:44 tux-116 coretemp
Jan 19 02:08:44 tux-116 snd
Jan 19 02:08:44 tux-116 tpm_tis
Jan 19 02:08:44 tux-116 tpm
Jan 19 02:08:44 tux-116 tpm_bios
Jan 19 02:08:44 tux-116 wmi
Jan 19 02:08:44 tux-116 button
Jan 19 02:08:44 tux-116 processor
Jan 19 02:08:44 tux-116 evdev
Jan 19 02:08:44 tux-116 thermal_sys
Jan 19 02:08:44 tux-116 psmouse
Jan 19 02:08:44 tux-116 i2c_core
Jan 19 02:08:44 tux-116 soundcore
Jan 19 02:08:44 tux-116 snd_page_alloc
Jan 19 02:08:44 tux-116 serio_raw
Jan 19 02:08:44 tux-116 ext4
Jan 19 02:08:44 tux-116 mbcache
Jan 19 02:08:44 tux-116 jbd2
Jan 19 02:08:44 tux-116 crc16
Jan 19 02:08:44 tux-116 dm_mod
Jan 19 02:08:44 tux-116 raid10
Jan 19 02:08:44 tux-116 raid456
Jan 19 02:08:44 tux-116 async_raid6_recov
Jan 19 02:08:44 tux-116 async_pq
Jan 19 02:08:44 tux-116 raid6_pq
Jan 19 02:08:44 tux-116 async_xor
Jan 19 02:08:44 tux-116 xor
Jan 19 02:08:44 tux-116 async_memcpy
Jan 19 02:08:44 tux-116 async_tx
Jan 19 02:08:44 tux-116 raid1
Jan 19 02:08:44 tux-116 raid0
Jan 19 02:08:44 tux-116 multipath
Jan 19 02:08:44 tux-116 linear
Jan 19 02:08:44 tux-116 md_mod
Jan 19 02:08:44 tux-116 usbhid
Jan 19 02:08:44 tux-116 hid
Jan 19 02:08:44 tux-116 sg
Jan 19 02:08:44 tux-116 sr_mod
Jan 19 02:08:44 tux-116 sd_mod
Jan 19 02:08:44 tux-116 cdrom
Jan 19 02:08:44 tux-116 crc_t10dif
Jan 19 02:08:44 tux-116 ahci
Jan 19 02:08:44 tux-116 libahci
Jan 19 02:08:44 tux-116 crc32c_intel
Jan 19 02:08:44 tux-116 ghash_clmulni_intel
Jan 19 02:08:44 tux-116 ehci_hcd
Jan 19 02:08:44 tux-116 ata_generic
Jan 19 02:08:44 tux-116 aesni_intel
Jan 19 02:08:44 tux-116 cryptd
Jan 19 02:08:44 tux-116 libata
Jan 19 02:08:44 tux-116 aes_x86_64
Jan 19 02:08:44 tux-116 scsi_mod
Jan 19 02:08:44 tux-116 aes_generic
Jan 19 02:08:44 tux-116 e1000e
Jan 19 02:08:44 tux-116 usbcore
Jan 19 02:08:44 tux-116 usb_common
Jan 19 02:08:44 tux-116 [last unloaded: microcode]
Jan 19 02:08:44 tux-116 
Jan 19 02:08:44 tux-116 [120882.927712] 
Jan 19 02:08:44 tux-116 [120882.927718] Pid: 16263, comm: run_EM.sh Tainted: P           O 3.2.0-0.bpo.4-amd64 #1 Debian 3.2.35-2~bpo60+1
Jan 19 02:08:44 tux-116 Hewlett-Packard HP Compaq 8200 Elite CMT PC
Jan 19 02:08:44 tux-116 /1494
Jan 19 02:08:44 tux-116 
Jan 19 02:08:44 tux-116 [120882.927733] RIP: 0010:[<ffffffffa103c5f7>] 
Jan 19 02:08:44 tux-116 [<ffffffffa103c5f7>] __fscache_read_or_alloc_pages+0x194/0x262 [fscache]
Jan 19 02:08:44 tux-116 [120882.927745] RSP: 0018:ffff8801f63119d8  EFLAGS: 00010246
Jan 19 02:08:44 tux-116 [120882.927749] RAX: 0000000000000000 RBX: ffff8802112b4198 RCX: ffff8801f6311968
Jan 19 02:08:44 tux-116 [120882.927754] RDX: 0000000000000000 RSI: ffff8801f6311958 RDI: ffff88022dfbea20
Jan 19 02:08:44 tux-116 [120882.927759] RBP: ffff8801f6311a94 R08: ffff8801f6310000 R09: ffff88022dc0eab0
Jan 19 02:08:44 tux-116 [120882.927763] R10: 0000000000000286 R11: 0000000000000000 R12: ffff8801f6311b98
Jan 19 02:08:44 tux-116 [120882.927767] R13: ffff8801f6019180 R14: ffff8801f6411940 R15: 00000000000200da
Jan 19 02:08:44 tux-116 [120882.927772] FS:  00002acadfa6f700(0000) GS:ffff88022dc00000(0000) knlGS:0000000000000000
Jan 19 02:08:44 tux-116 [120882.927778] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
Jan 19 02:08:44 tux-116 [120882.927785] CR2: 0000000000000040 CR3: 0000000221977000 CR4: 00000000000406f0
Jan 19 02:08:44 tux-116 [120882.927790] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Jan 19 02:08:44 tux-116 [120882.927794] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Jan 19 02:08:44 tux-116 [120882.927799] Process run_EM.sh (pid: 16263, threadinfo ffff8801f6310000, task ffff8802210d0870)
Jan 19 02:08:44 tux-116 [120882.927805] Stack:
Jan 19 02:08:44 tux-116 [120882.927809]  ffff88022241b440
Jan 19 02:08:44 tux-116 ffffffffa108eacf
Jan 19 02:08:44 tux-116 0000000000000000
Jan 19 02:08:44 tux-116 ffff8801f71bedb8
Jan 19 02:08:44 tux-116 
Jan 19 02:08:44 tux-116 [120882.927828]  ffff8801f6311a94
Jan 19 02:08:44 tux-116 ffff8801f6311b98
Jan 19 02:08:44 tux-116 0000000000000004
Jan 19 02:08:44 tux-116 ffff8801f71beef8
Jan 19 02:08:44 tux-116 
Jan 19 02:08:44 tux-116 [120882.927843]  00000000ffffff97
Jan 19 02:08:44 tux-116 ffffffffa108ea04
Jan 19 02:08:44 tux-116 00000010000200da
Jan 19 02:08:44 tux-116 0000000000000024
Jan 19 02:08:44 tux-116 
Jan 19 02:08:44 tux-116 [120882.927864] Call Trace:
Jan 19 02:08:44 tux-116 [120882.927876]  [<ffffffffa108eacf>] ? __nfs_readpages_from_fscache+0x146/0x146 [nfs]
Jan 19 02:08:44 tux-116 [120882.927886]  [<ffffffffa108ea04>] ? __nfs_readpages_from_fscache+0x7b/0x146 [nfs]
Jan 19 02:08:44 tux-116 [120882.927893]  [<ffffffffa106dceb>] ? nfs_readpages+0xe1/0x157 [nfs]
Jan 19 02:08:44 tux-116 [120882.927902]  [<ffffffff810efd44>] ? alloc_pages_current+0xbb/0xd8
Jan 19 02:08:44 tux-116 [120882.927909]  [<ffffffff810c608e>] ? __do_page_cache_readahead+0x124/0x1ca
Jan 19 02:08:44 tux-116 [120882.927917]  [<ffffffff810c6150>] ? ra_submit+0x1c/0x20
Jan 19 02:08:44 tux-116 [120882.927924]  [<ffffffff810be4b8>] ? generic_file_aio_read+0x299/0x5d0
Jan 19 02:08:44 tux-116 [120882.927930]  [<ffffffff8103b982>] ? __wake_up+0x35/0x46
Jan 19 02:08:44 tux-116 [120882.927939]  [<ffffffffa1063bf2>] ? nfs_file_read+0x9d/0xbe [nfs]
Jan 19 02:08:44 tux-116 [120882.927945]  [<ffffffff8110655d>] ? do_sync_read+0xba/0xf3
Jan 19 02:08:44 tux-116 [120882.927951]  [<ffffffff81106fb0>] ? vfs_read+0xa1/0xfb
Jan 19 02:08:44 tux-116 [120882.927957]  [<ffffffff8110b34a>] ? get_user_arg_ptr+0x47/0x5b
Jan 19 02:08:44 tux-116 [120882.927963]  [<ffffffff8110c215>] ? kernel_read+0x39/0x47
Jan 19 02:08:44 tux-116 [120882.927970]  [<ffffffff8110ce61>] ? do_execve_common+0x161/0x30f
Jan 19 02:08:44 tux-116 [120882.927975]  [<ffffffff811c5cdb>] ? strncpy_from_user+0x40/0x6d
Jan 19 02:08:44 tux-116 [120882.927982]  [<ffffffff8101495c>] ? sys_execve+0x3f/0x54
Jan 19 02:08:44 tux-116 [120882.927989]  [<ffffffff8136daac>] ? stub_execve+0x6c/0xc0
Jan 19 02:08:44 tux-116 [120882.927994] Code: 
Jan 19 02:08:44 tux-116 85 
Jan 19 02:08:44 tux-116 c0 
Jan 19 02:08:44 tux-116 74 
Jan 19 02:08:44 tux-116 06 
Jan 19 02:08:44 tux-116 48 
Jan 19 02:08:44 tux-116 8b 
Jan 19 02:08:44 tux-116 7a 
Jan 19 02:08:44 tux-116 28 
Jan 19 02:08:44 tux-116 ff 
Jan 19 02:08:44 tux-116 d0 
Jan 19 02:08:44 tux-116 48 
Jan 19 02:08:44 tux-116 c7 
Jan 19 02:08:44 tux-116 c1 
Jan 19 02:08:44 tux-116 7c 
Jan 19 02:08:44 tux-116 06 
Jan 19 02:08:44 tux-116 04 
Jan 19 02:08:44 tux-116 a1 
Jan 19 02:08:44 tux-116 48 
Jan 19 02:08:44 tux-116 c7 
Jan 19 02:08:44 tux-116 c2 
Jan 19 02:08:44 tux-116 84 
Jan 19 02:08:44 tux-116 06 
Jan 19 02:08:44 tux-116 04 
Jan 19 02:08:44 tux-116 a1 
Jan 19 02:08:44 tux-116 4c 
Jan 19 02:08:44 tux-116 89 
Jan 19 02:08:44 tux-116 ee 
Jan 19 02:08:44 tux-116 4c 
Jan 19 02:08:44 tux-116 89 
Jan 19 02:08:44 tux-116 f7 
Jan 19 02:08:44 tux-116 e8 
Jan 19 02:08:44 tux-116 36 
Jan 19 02:08:44 tux-116 fc 
Jan 19 02:08:44 tux-116 ff 
Jan 19 02:08:44 tux-116 ff 
Jan 19 02:08:44 tux-116 85 
Jan 19 02:08:44 tux-116 c0 
Jan 19 02:08:44 tux-116 78 
Jan 19 02:08:44 tux-116 59 
Jan 19 02:08:44 tux-116 49 
Jan 19 02:08:44 tux-116 8b 
Jan 19 02:08:44 tux-116 46 
Jan 19 02:08:44 tux-116 70 
Jan 19 02:08:44 tux-116 8b 
Jan 19 02:08:44 tux-116 40 
Jan 19 02:08:44 tux-116 40 
Jan 19 02:08:44 tux-116 a8 
Jan 19 02:08:44 tux-116 04 
Jan 19 02:08:44 tux-116 74 
Jan 19 02:08:44 tux-116 29 
Jan 19 02:08:44 tux-116 f0 
Jan 19 02:08:44 tux-116 ff 
Jan 19 02:08:44 tux-116 05 
Jan 19 02:08:44 tux-116 66 
Jan 19 02:08:44 tux-116 41 
Jan 19 02:08:44 tux-116 00 
Jan 19 02:08:44 tux-116 00 
Jan 19 02:08:44 tux-116 49 
Jan 19 02:08:44 tux-116 8b 
Jan 19 02:08:44 tux-116 46 
Jan 19 02:08:44 tux-116 68 
Jan 19 02:08:44 tux-116 44 
Jan 19 02:08:44 tux-116 89 
Jan 19 02:08:44 tux-116 
Jan 19 02:08:44 tux-116 [120882.928292] RIP 
Jan 19 02:08:44 tux-116 [<ffffffffa103c5f7>] __fscache_read_or_alloc_pages+0x194/0x262 [fscache]
Jan 19 02:08:44 tux-116 [120882.928304]  RSP <ffff8801f63119d8>
Jan 19 02:08:44 tux-116 [120882.928309] CR2: 0000000000000040
Jan 19 02:08:44 tux-116 [120882.928348] ---[ end trace 87eba6a8e7d80e34 ]---
Jan 19 02:08:44 tux-116 [120882.928355] Kernel panic - not syncing: Fatal exception
Jan 19 02:08:44 tux-116 [120882.928360] Pid: 16263, comm: run_EM.sh Tainted: P      D    O 3.2.0-0.bpo.4-amd64 #1 Debian 3.2.35-2~bpo60+1
Jan 19 02:08:44 tux-116 [120882.928367] Call Trace:
Jan 19 02:08:44 tux-116 [120882.928373]  [<ffffffff8136627d>] ? panic+0x92/0x1aa
Jan 19 02:08:44 tux-116 [120882.928438]  [<ffffffff81049e84>] ? kmsg_dump+0x41/0xdd
Jan 19 02:08:44 tux-116 [120882.928446]  [<ffffffff81368f41>] ? oops_end+0xa9/0xb6
Jan 19 02:08:44 tux-116 [120882.928470]  [<ffffffff8102fd85>] ? no_context+0x1ff/0x20c
Jan 19 02:08:44 tux-116 [120882.928476]  [<ffffffff8100d6b0>] ? __switch_to+0x1c9/0x2b1
Jan 19 02:08:44 tux-116 [120882.928482]  [<ffffffff8136b112>] ? do_page_fault+0x215/0x34c
Jan 19 02:08:44 tux-116 [120882.928487]  [<ffffffff81366b6c>] ? __schedule+0x5a0/0x5cd
Jan 19 02:08:44 tux-116 [120882.928494]  [<ffffffffa1039ed2>] ? fscache_wait_bit+0xd/0xd [fscache]
Jan 19 02:08:44 tux-116 [120882.928501]  [<ffffffffa1039ed2>] ? fscache_wait_bit+0xd/0xd [fscache]
Jan 19 02:08:44 tux-116 [120882.928508]  [<ffffffff81368635>] ? page_fault+0x25/0x30
Jan 19 02:08:44 tux-116 [120882.928514]  [<ffffffffa103c5f7>] ? __fscache_read_or_alloc_pages+0x194/0x262 [fscache]
Jan 19 02:08:44 tux-116 [120882.928521]  [<ffffffffa103c5ef>] ? __fscache_read_or_alloc_pages+0x18c/0x262 [fscache]
Jan 19 02:08:44 tux-116 [120882.928530]  [<ffffffffa108eacf>] ? __nfs_readpages_from_fscache+0x146/0x146 [nfs]
Jan 19 02:08:44 tux-116 [120882.928601]  [<ffffffffa108ea04>] ? __nfs_readpages_from_fscache+0x7b/0x146 [nfs]
Jan 19 02:08:44 tux-116 [120882.928611]  [<ffffffffa106dceb>] ? nfs_readpages+0xe1/0x157 [nfs]
Jan 19 02:08:44 tux-116 [120882.928618]  [<ffffffff810efd44>] ? alloc_pages_current+0xbb/0xd8
Jan 19 02:08:44 tux-116 [120882.928623]  [<ffffffff810c608e>] ? __do_page_cache_readahead+0x124/0x1ca
Jan 19 02:08:44 tux-116 [120882.928629]  [<ffffffff810c6150>] ? ra_submit+0x1c/0x20
Jan 19 02:08:44 tux-116 [120882.928635]  [<ffffffff810be4b8>] ? generic_file_aio_read+0x299/0x5d0
Jan 19 02:08:44 tux-116 [120882.928641]  [<ffffffff8103b982>] ? __wake_up+0x35/0x46
Jan 19 02:08:44 tux-116 [120882.928725]  [<ffffffffa1063bf2>] ? nfs_file_read+0x9d/0xbe [nfs]
Jan 19 02:08:44 tux-116 [120882.928727]  [<ffffffff8110655d>] ? do_sync_read+0xba/0xf3
Jan 19 02:08:44 tux-116 [120882.928729]  [<ffffffff81106fb0>] ? vfs_read+0xa1/0xfb
Jan 19 02:08:44 tux-116 [120882.928731]  [<ffffffff8110b34a>] ? get_user_arg_ptr+0x47/0x5b
Jan 19 02:08:44 tux-116 [120882.928732]  [<ffffffff8110c215>] ? kernel_read+0x39/0x47

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