Date:   Tue, 12 Feb 2019 11:21:57 -0500
From:   Murphy Zhou <jencce.kernel@gmail.com>
To:     linux-nfs@vger.kernel.org
Cc:     gregkh@linuxfoundation.org
Subject: [v5.0-rc3 regression] Oops when starting nfs service
Message-ID: <20190212162157.GA27459@sh-el5.eng.rdu2.redhat.com>
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Hi,

Starting nfs-server service can crash the kernel since
commit ff9fb72bc07705c00795ca48631f7fffe24d2c6b
Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date:   Wed Jan 23 11:28:14 2019 +0100

    debugfs: return error values, not NULL

# git describe ff9fb72bc07705c00795ca48631f7fffe24d2c6b
v5.0-rc2-3-gff9fb72bc077

Reverting this commit prevents the crash.

It can be reproduced simply by:
# systemctl start nfs-server

Thanks.

# bisect log
#
git bisect start
# good: [74e96711e3379fc66630f2a1d184947f80cf2c48] Merge tag 'platform-drivers-x86-v5.0-2' of git://git.infradead.org/linux-platform-drivers-x86
git bisect good 74e96711e3379fc66630f2a1d184947f80cf2c48
# bad: [27b4ad621e887ce8e5eb508a0103f13d30f6b38a] Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
git bisect bad 27b4ad621e887ce8e5eb508a0103f13d30f6b38a
# good: [bdcc5bc25548ef6b08e2e43937148f907c212292] mISDN: fix a race in dev_expire_timer()
git bisect good bdcc5bc25548ef6b08e2e43937148f907c212292
# good: [e22a15d1c4b36877934ab360aace41ddf8a6577c] Merge tag 'tty-5.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
git bisect good e22a15d1c4b36877934ab360aace41ddf8a6577c
# bad: [680905431b9de8c7224b15b76b1826a1481cfeaf] Merge tag 'char-misc-5.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
git bisect bad 680905431b9de8c7224b15b76b1826a1481cfeaf
# bad: [8c8e62cc983938a554d39497b5600b842f8a7965] Merge tag 'driver-core-5.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
git bisect bad 8c8e62cc983938a554d39497b5600b842f8a7965
# good: [6d923f8fe821c0c6b5378635cbcc9da5f5ec520a] Merge tag 'iio-fixes-5.0a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-linus
git bisect good 6d923f8fe821c0c6b5378635cbcc9da5f5ec520a
# bad: [37ea7b630ae5cdea4e8ff381d9d23abfef5939e6] debugfs: debugfs_lookup() should return NULL if not found
git bisect bad 37ea7b630ae5cdea4e8ff381d9d23abfef5939e6
# good: [d88c93f090f708c18195553b352b9f205e65418f] debugfs: fix debugfs_rename parameter checking
git bisect good d88c93f090f708c18195553b352b9f205e65418f
# bad: [ff9fb72bc07705c00795ca48631f7fffe24d2c6b] debugfs: return error values, not NULL
git bisect bad ff9fb72bc07705c00795ca48631f7fffe24d2c6b
# first bad commit: [ff9fb72bc07705c00795ca48631f7fffe24d2c6b] debugfs: return error values, not NULL
[

# call trace
#
[ 9082.260783] Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
[ 9082.442808] NFSD: starting 45-second grace period (net f00000a8)
[ 9082.533649] BUG: unable to handle kernel NULL pointer dereference at 000000000000001b
[ 9082.569586] #PF error: [normal kernel read fault]
[ 9082.591405] PGD 0 P4D 0
[ 9082.602752] Oops: 0000 [#1] SMP PTI
[ 9082.618820] CPU: 9 PID: 1183 Comm: gssproxy Not tainted 5.0.0-rc6-master-aa0c38cf39de+ #11
[ 9082.656683] Hardware name: HP ProLiant DL388p Gen8, BIOS P70 09/18/2013
[ 9082.686695] RIP: 0010:rpc_clnt_debugfs_register+0xb4/0x120 [sunrpc]
[ 9082.715173] Code: be 00 81 00 00 48 c7 c7 be b0 5e c0 e8 f5 13 79 e4 48 85 c0 74 31 48 8b 43 30 48 8b 80 f0 04 00 00 48 85 c0 0f 84 70 ff ff ff <48> 8b 48 28 48 c7 c2 c4 b0 5e c0 be 18 00 00 00 48 89 e7 e8 54 78
[ 9082.800976] RSP: 0018:ffffadd344c97b68 EFLAGS: 00010286
[ 9082.824946] RAX: fffffffffffffff3 RBX: ffff99b6dda0ba00 RCX: ffff99b6dda0ba00
[ 9082.857720] RDX: fffffffffffffff3 RSI: fffffffffffffff3 RDI: ffffffffc05eb0be
[ 9082.890558] RBP: ffff99b6dd724140 R08: ffffffffa584e760 R09: ffffffffc05e8700
[ 9082.923165] R10: 0000000000000000 R11: ffffadd344c97b69 R12: ffff99b6eebdc800
[ 9082.955485] R13: ffffffffa5d98c80 R14: 0000000000000000 R15: ffffadd344c97d30
[ 9082.987929] FS:  00007f97b0b01c80(0000) GS:ffff99b6ef4c0000(0000) knlGS:0000000000000000
[ 9083.024017] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9083.050402] CR2: 000000000000001b CR3: 0000000827d3c004 CR4: 00000000001606e0
[ 9083.083171] Call Trace:
[ 9083.094594]  ? ida_alloc_range+0x35d/0x3c0
[ 9083.113081]  rpc_client_register+0x42/0x1a0 [sunrpc]
[ 9083.135947]  ? _cond_resched+0x15/0x30
[ 9083.153429]  ? __kmalloc+0x164/0x200
[ 9083.169633]  rpc_new_client+0x1d8/0x290 [sunrpc]
[ 9083.190656]  rpc_create_xprt+0x63/0x190 [sunrpc]
[ 9083.212003]  ? rpc_xprt_debugfs_register+0x88/0xd0 [sunrpc]
[ 9083.237454]  rpc_create+0xfe/0x1e0 [sunrpc]
[ 9083.256338]  ? terminate_walk+0xe4/0x100
[ 9083.273969]  ? path_openat+0x3d8/0x1670
[ 9083.291880]  gssp_rpc_create+0x89/0xe0 [auth_rpcgss]
[ 9083.314561]  set_gssp_clnt+0x4c/0xa0 [auth_rpcgss]
[ 9083.336649]  write_gssp+0x94/0xf0 [auth_rpcgss]
[ 9083.357420]  proc_reg_write+0x39/0x60
[ 9083.375163]  __vfs_write+0x36/0x1b0
[ 9083.391688]  ? selinux_file_permission+0xf0/0x130
[ 9083.415432]  ? security_file_permission+0x2e/0xe0
[ 9083.437427]  vfs_write+0xa5/0x1a0
[ 9083.452508]  ksys_write+0x4f/0xb0
[ 9083.467803]  do_syscall_64+0x55/0x1a0
[ 9083.484470]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 9083.507782] RIP: 0033:0x7f97aecf8aa7
[ 9083.524457] Code: c3 66 90 41 54 49 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 fb fc ff ff 4c 89 e2 48 89 ee 89 df 41 89 c0 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 48 89 44 24 08 e8 34 fd ff ff 48
[ 9083.610512] RSP: 002b:00007ffde9e42a20 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
[ 9083.645486] RAX: ffffffffffffffda RBX: 000000000000000b RCX: 00007f97aecf8aa7
[ 9083.678203] RDX: 0000000000000001 RSI: 00007ffde9e42a56 RDI: 000000000000000b
[ 9083.711049] RBP: 00007ffde9e42a56 R08: 0000000000000000 R09: 0000000000000007
[ 9083.743465] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
[ 9083.775516] R13: 0000560adff33c00 R14: 0000000000000000 R15: 0000000000000001
[ 9083.808494] Modules linked in: nfsd auth_rpcgss nfs_acl lockd grace sunrpc intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm ipmi_ssif irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel intel_cstate ipmi_si intel_uncore ipmi_devintf iTCO_wdt iTCO_vendor_support pcspkr intel_rapl_perf ioatdma lpc_ich ipmi_msghandler sg hpilo hpwdt dca acpi_power_meter xfs libcrc32c ata_generic mgag200 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sd_mod sysimgblt fb_sys_fops ttm ata_piix drm libata serio_raw crc32c_intel tg3 hpsa scsi_transport_sas dm_mirror dm_region_hash dm_log dm_mod
[ 9084.057815] CR2: 000000000000001b
[ 9084.072727] ---[ end trace 9d6f1665267a702c ]---
[ 9084.094005] RIP: 0010:rpc_clnt_debugfs_register+0xb4/0x120 [sunrpc]
[ 9084.122922] Code: be 00 81 00 00 48 c7 c7 be b0 5e c0 e8 f5 13 79 e4 48 85 c0 74 31 48 8b 43 30 48 8b 80 f0 04 00 00 48 85 c0 0f 84 70 ff ff ff <48> 8b 48 28 48 c7 c2 c4 b0 5e c0 be 18 00 00 00 48 89 e7 e8 54 78
[ 9084.209159] RSP: 0018:ffffadd344c97b68 EFLAGS: 00010286
[ 9084.232809] RAX: fffffffffffffff3 RBX: ffff99b6dda0ba00 RCX: ffff99b6dda0ba00
[ 9084.265416] RDX: fffffffffffffff3 RSI: fffffffffffffff3 RDI: ffffffffc05eb0be
[ 9084.297480] RBP: ffff99b6dd724140 R08: ffffffffa584e760 R09: ffffffffc05e8700
[ 9084.330637] R10: 0000000000000000 R11: ffffadd344c97b69 R12: ffff99b6eebdc800
[ 9084.363159] R13: ffffffffa5d98c80 R14: 0000000000000000 R15: ffffadd344c97d30
[ 9084.395817] FS:  00007f97b0b01c80(0000) GS:ffff99b6ef4c0000(0000) knlGS:0000000000000000
[ 9084.432989] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9084.460595] CR2: 000000000000001b CR3: 0000000827d3c004 CR4: 00000000001606e0
[ 9084.493254] Kernel panic - not syncing: Fatal exception
[ 9084.517838] Kernel Offset: 0x23a00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 9084.567110] ---[ end Kernel panic - not syncing: Fatal exception ]---
[ 9084.596773] ------------[ cut here ]------------