Date:   Mon, 21 Nov 2016 20:02:13 +0000
From:   "Pandruvada, Srinivas" <srinivas.pandruvada@...el.com>
To:     "tglx@...utronix.de" <tglx@...utronix.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "Zhang, Rui" <rui.zhang@...el.com>,
        "edubezval@...il.com" <edubezval@...il.com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "bp@...en8.de" <bp@...en8.de>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        "rt@...utronix.de" <rt@...utronix.de>
Subject: Re: [patch 00/12] thermal/x86_pkg_temp: Sanitize yet another
 hotplug and locking trainwreck

On Fri, 2016-11-18 at 00:03 +0000, Thomas Gleixner wrote:
> We solely intended to convert that driver to the hotplug state
> machine and
> stumbled over a large pile of insanities, which are all interwoven
> with the
> package management:

Thanks Thomas for fixes.
But I did a very simple test on 4.9.0-rc5 on a client machine, just
rmmod and read zone, it will cause crash. I have not tested on a multi-
socket system, which is also required where the real test of  last cpu
on a package goes offline can be tested.

$ uname -a
Linux xxx 4.9.0-rc5+ #47 SMP Mon Nov 21 11:30:56 PST 2016 x86_64 x86_64
x86_64 GNU/Linux

$ pwd
/sys/devices/virtual/thermal/thermal_zone8
$ cat type 
x86_pkg_temp
$ cat temp 
43000
$ lsmod | grep x86
x86_pkg_temp_thermal    16384  0
aes_x86_64             20480  1 aesni_intel
$ sudo rmmod x86_pkg_temp_thermal
$ cd ../thermal_zone8

Zone is not removed on rmmod!!!, so any read on zone will cause crash

$ ls
available_policies  k_d   k_pu	  power      sustainable_power	
trip_point_0_type  type
emul_temp	    k_i   offset  slope      temp		trip_
point_1_temp  uevent
integral_cutoff     k_po  policy  subsystem  trip_point_0_temp	t
rip_point_1_type
spandruvada@...ndruv-mobl2:/sys/devices/virtual/thermal/thermal_zone8$
cat temp 
Killed
spandruvada@...ndruv-mobl2:/sys/devices/virtual/thermal/thermal_zone8$ 




[  116.726989] BUG: unable to handle kernel paging request at
ffffffffa07b8010
[  116.727103] IP: [<ffffffff81677cdd>]
thermal_zone_get_temp+0x3d/0x100
[  116.727192] PGD 2e0d067 
[  116.727224] PUD 2e0e063 
[  116.727259] PMD 14266c067 
[  116.727278] PTE 0

[  116.727328] Oops: 0000 [#1] SMP
[  116.727368] Modules linked in: rfcomm vmw_vsock_vmci_transport vsock
vmw_vmci asix usbnet mii binfmt_misc bnep hid_sensor_rotation
hid_sensor_als hid_sensor_incl_3d hid_sensor_accel_3d
hid_sensor_magn_3d hid_sensor_gyro_3d hid_sensor_trigger
hid_sensor_custom joydev hid_sensor_iio_common pn544_mei hid_rmi
mei_phy hid_multitouch pn544 hci hid_sensor_hub nfc intel_rapl
nls_iso8859_1 uvcvideo coretemp crct10dif_pclmul crc32_pclmul
ghash_clmulni_intel videobuf2_vmalloc videobuf2_memops aesni_intel
videobuf2_v4l2 option aes_x86_64 usb_wwan videobuf2_core lrw usbserial
gf128mul glue_helper ablk_helper videodev btusb cryptd btrtl btbcm
iwlwifi btintel serio_raw bluetooth intel_pch_thermal cfg80211
snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic
snd_hda_intel battery snd_hda_codec snd_hda_core
[  116.728433]  winbond_cir int3403_thermal rc_core snd_hwdep
snd_seq_midi snd_pcm snd_seq_midi_event mac_hid snd_rawmidi dw_dmac
int3402_thermal snd_seq 8250_dw i2c_designware_platform snd_seq_device
spi_pxa2xx_platform i2c_designware_core snd_timer int3400_thermal
acpi_thermal_rel snd mei_me processor_thermal_device mei
int340x_thermal_zone lpc_ich intel_soc_dts_iosf soundcore nfsd
auth_rpcgss kvm_intel nfs_acl lockd kvm grace irqbypass sunrpc cuse
parport_pc ppdev lp parport autofs4 hid_generic usbhid i915
i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt
fb_sys_fops drm ahci libahci video i2c_hid hid sdhci_acpi sdhci [last
unloaded: x86_pkg_temp_thermal]
[  116.729342] CPU: 1 PID: 2431 Comm: cat Not tainted 4.9.0-rc5+ #47
[  116.729413] Hardware name: Intel Corporation Shark Bay Client
platform/Harris Beach SDS, BIOS HSWLPTU1.86C.0133.R00.1309172123
09/17/2013
[  116.729547] task: ffff880124288000 task.stack: ffffc90000cf4000
[  116.729614] RIP: 0010:[<ffffffff81677cdd>]  [<ffffffff81677cdd>]
thermal_zone_get_temp+0x3d/0x100
[  116.729721] RSP: 0018:ffffc90000cf7cd8  EFLAGS: 00010287
[  116.729783] RAX: 00000000ffffffea RBX: ffff880114de2000 RCX:
ffff88010f89d4c0
[  116.729862] RDX: ffffffffa07b8000 RSI: ffffc90000cf7d1c RDI:
ffff880114c5a000
[  116.729942] RBP: ffffc90000cf7d08 R08: 0000000000000000 R09:
0000000000000000
[  116.730021] R10: 000000001cffdcff R11: 0000000000000001 R12:
ffff880114c5a028
[  116.730101] R13: ffffffff81a7aab0 R14: ffff880113a53800 R15:
ffff88012fdcc200
[  116.730182] FS:  00007f40bf57e700(0000) GS:ffff88014f280000(0000)
knlGS:0000000000000000
[  116.730272] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  116.730337] CR2: ffffffffa07b8010 CR3: 0000000010130000 CR4:
00000000001406e0
[  116.730418] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[  116.730497] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
0000000000000400
[  116.730576] Stack:
[  116.730603]  0000000000000282 ffffffff7fffffff ffff880114de2000
ffff880114c5a028
[  116.736697]  ffffffff81a7aab0 ffff880113a53800 ffffc90000cf7d28
ffffffff8167826e
[  116.742680]  0000000000000246 ffffffff81f19e20 ffffc90000cf7d48
ffffffff8154c910
[  116.748607] Call Trace:
[  116.754349]  [<ffffffff8167826e>] temp_show+0x1e/0x40
[  116.759705]  [<ffffffff8154c910>] dev_attr_show+0x20/0x50
[  116.764841]  [<ffffffff812a50c1>] ? sysfs_file_ops+0x41/0x60
[  116.769056]  [<ffffffff812a5411>] sysfs_kf_seq_show+0xc1/0x120
[  116.773282]  [<ffffffff812a39f6>] kernfs_seq_show+0x26/0x30
[  116.777457]  [<ffffffff8124995f>] seq_read+0xcf/0x380
[  116.781649]  [<ffffffff812a4a4b>] kernfs_fop_read+0x11b/0x1a0
[  116.785727]  [<ffffffff81221968>] __vfs_read+0x28/0x110
[  116.789796]  [<ffffffff813526ab>] ?
security_file_permission+0x9b/0xc0
[  116.793605]  [<ffffffff81221dee>] ? rw_verify_area+0x4e/0xb0
[  116.795640]  [<ffffffff81221ee3>] vfs_read+0x93/0x130
[  116.797212]  [<ffffffff812232e9>] SyS_read+0x49/0xa0
[  116.798715]  [<ffffffff81003bfe>] do_syscall_64+0x6e/0x180
[  116.800224]  [<ffffffff8181c234>]
entry_SYSCALL64_slow_path+0x25/0x25
[  116.801709] Code: 41 54 53 48 83 ec 10 48 85 ff c7 45 d8 ff ff ff 7f
0f 84 a3 00 00 00 48 81 ff 00 f0 ff ff 0f 87 96 00 00 00 48 8b 97 a0 04
00 00 <48> 83 7a 10 00 0f 84 84 00 00 00 4c 8d b7 30 05 00 00 48 89 fb 
[  116.803334] RIP  [<ffffffff81677cdd>]
thermal_zone_get_temp+0x3d/0x100
[  116.804877]  RSP <ffffc90000cf7cd8>
[  116.806378] CR2: ffffffffa07b8010
[  116.815516] ---[ end trace 593a281d67d382bb ]---


Thanks,
Srinivas

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