Re: NULL pointer dereference

["Alexander V. Makartsev" <avbetev@gmail.com>]

On 19.12.2020 21:13, Grzesiek Sójka wrote:

> Hi there,
>       
>       
>       I found the following in my "server" log:
>       
>       
>       ==============================================
>       
>       
>       BUG: unable to handle kernel NULL pointer dereference at
>       0000000000000008
>       
>       PGD 0 P4D 0
>       
>       Oops: 0000 [#2] SMP PTI
>       
>       CPU: 5 PID: 12441 Comm: awk Tainted: G      D          
>       4.19.0-13-amd64 #1 Debian 4.19.160-2
>       
>       Hardware name: FUJITSU D3162-B1/D3162-B1, BIOS V4.6.5.3 R1.23.0
>       for D3162-B1x 12/01/2014
>       
>       RIP: 0010:unmap_page_range+0x561/0xa60
>       
>       Code: 80 00 00 00 01 e8 4f 2b 01 00 49 8b 07 f6 c4 80 0f 84 0e 03
>       00 00 4c 89 ff e8 6b 91 fe ff 85 c0 0f 88 e6 02 00 00 49 8b 46 28
>       <8b> 50 08 8d 4a 01 89 48 08 4c 89 7c d0 10 3b 48 0c 0f 84
>       d2 00 00
>       
>       RSP: 0018:ffff9c3a49167cd0 EFLAGS: 00010206
>       
>       RAX: 0000000000000000 RBX: ffff8e2f47a83a10 RCX: 0000000000000001
>       
>       RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8e2f7dd20000
>       
>       RBP: 00007faa2ed43000 R08: 0000000000000000 R09: ffff8e2ef8ae1c70
>       
>       R10: ffff8e2f9e5df000 R11: 0000000000000000 R12: 00007faa2ed42000
>       
>       R13: 000000014fd44025 R14: ffff9c3a49167dd0 R15: ffffd073853f5100
>       
>       FS:  0000000000000000(0000) GS:ffff8e2f7e140000(0000)
>       knlGS:0000000000000000
>       
>       CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>       
>       CR2: 0000000000000008 CR3: 000000015020a003 CR4: 00000000000606e0
>       
>       Call Trace:
>       
>        unmap_vmas+0x7f/0xb0
>       
>        exit_mmap+0xaa/0x180
>       
>        mmput+0x54/0x130
>       
>        do_exit+0x33f/0xbb0
>       
>        ? handle_mm_fault+0xd6/0x200
>       
>        do_group_exit+0x3a/0xa0
>       
>        __x64_sys_exit_group+0x14/0x20
>       
>        do_syscall_64+0x53/0x110
>       
>        entry_SYSCALL_64_after_hwframe+0x44/0xa9
>       
>       RIP: 0033:0x7faa2eaa99d6
>       
>       Code: Bad RIP value.
>       
>       RSP: 002b:00007ffd860931d8 EFLAGS: 00000246 ORIG_RAX:
>       00000000000000e7
>       
>       RAX: ffffffffffffffda RBX: 00007faa2eb9a760 RCX: 00007faa2eaa99d6
>       
>       RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
>       
>       RBP: 0000000000000000 R08: 00000000000000e7 R09: ffffffffffffff80
>       
>       R10: 00007ffd86093096 R11: 0000000000000246 R12: 00007faa2eb9a760
>       
>       R13: 0000000000000001 R14: 00007faa2eba3428 R15: 0000000000000000
>       
>       Modules linked in: ppp_deflate cfg80211 rfkill 8021q garp stp mrp
>       llc ppp_async crc_ccitt ppp_generic slhc nfsd auth_rpcgss nfs_acl
>       lockd grace sunrpc xt_nat nft_chain_nat_ipv4 nf_nat_ipv4 nf_nat
>       nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c ipt_REJECT
>       nf_reject_ipv4 nft_limit xt_limit xt_tcpudp nft_compat x_tables
>       nft_counter nf_tables nfnetlink binfmt_misc bonding sch5636
>       sch56xx_common rc_it913x_v1 it913x af9033 dvb_usb_af9035
>       dvb_usb_v2 dvb_core rc_core snd_hda_codec_hdmi
>       snd_hda_codec_conexant snd_hda_codec_generic intel_rapl i915
>       x86_pkg_temp_thermal snd_hda_intel intel_powerclamp snd_hda_codec
>       coretemp snd_hda_core snd_hwdep snd_pcm xhci_pci ehci_pci ahci
>       snd_timer xhci_hcd drm_kms_helper ehci_hcd libahci kvm snd mei_wdt
>       tg3 iTCO_wdt irqbypass mei_me e1000e drm libata usbcore
>       
>        iTCO_vendor_support soundcore lpc_ich libphy mei i2c_algo_bit
>       usb_common mfd_core crct10dif_pclmul crc32_pclmul ppdev
>       ghash_clmulni_intel sg i2c_i801 intel_cstate evdev intel_uncore
>       pcc_cpufreq video parport_pc button intel_rapl_perf pcspkr parport
>       ext4 crc16 mbcache jbd2 crc32c_generic fscrypto ecb sd_mod
>       crc32c_intel aacraid aesni_intel aes_x86_64 crypto_simd scsi_mod
>       cryptd glue_helper thermal fan
>       
>       CR2: 0000000000000008
>       
>       ---[ end trace 1f0672175c6e1ff0 ]---
>       
>       RIP: 0010:unmap_page_range+0x55d/0xa60
>       
>       Code: ff 83 ac 84 80 00 00 00 01 e8 4f 2b 01 00 49 8b 07 f6 c4 80
>       0f 84 0e 03 00 00 4c 89 ff e8 6b 91 fe ff 85 c0 0f 88 e6 02 00 00
>       <49> 8b 46 28 8b 50 08 8d 4a 01 89 48 08 4c 89 7c d0 10 3b
>       48 0c 0f
>       
>       RSP: 0018:ffff9c3a43a67cd0 EFLAGS: 00010202
>       
>       RAX: 0000000000000004 RBX: ffff8e2f47a0deb0 RCX: 0000000000000001
>       
>       RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8e2f7dd20000
>       
>       RBP: 00007f9f121d7000 R08: 0000000000000000 R09: ffff8e2f6a6e09c0
>       
>       R10: ffff8e2f9e5df000 R11: 0000000000000000 R12: 00007f9f121d6000
>       
>       R13: 000000081e49f025 R14: ffff9c3a43a67dd0 R15: ffffd073a07927c0
>       
>       FS:  0000000000000000(0000) GS:ffff8e2f7e140000(0000)
>       knlGS:0000000000000000
>       
>       CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>       
>       CR2: 00007faa2eaa99ac CR3: 000000015020a003 CR4: 00000000000606e0
>       
>       Fixing recursive fault but reboot is needed!
>       
>       
>       ============================================
>       
>       
>       This is not the first time, so I suspect a persistent problem. I
>       have no idea how to look for the solution. Any suggestions??
>       
>     
    If this is recurring error, was it identical in terms of codes,
    trace and register data?
    If it is not identical I suggest to start by checking RAM (and
    partially a CPU) with Memtest86+ [1]
    It will be good to know if hardware is fine anyway. Leave the test
    running overnight or longer. A 10 or so test passes should be enough
    to tell if RAM is good.
    Next I'd check official Fujitsu website for BIOS\BMC\Firmware
    updates for your server\motherboard and update to latest version
    available.
    It could be complicated and dangerous process, so be sure to first
    check out any relevant technical advisories from Fujitsu, that are
    available for your server system and official guides on update
    process.
    
    
    [1] https://www.memtest.org/
    
-- 
With kindest regards, Alexander.

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