tmpfs trips and kernel panics

[Jiri Svoboda]

To reproduce:

1. $ make PROFILE=amd64
2. $ tools/ew.py
3. # cd /tmp
4. # cp /demo.txt .
5. # edit demo.txt
6. Ctrl-S (saving the file fails)
7. Ctrl-Q
8. # edit demo.txt (file appears empty)
9. Ctrl-S (saving the file succeeds)
10. Ctrl-Q
11. # ls (kernel panic)

This problem does not occur on / (ext4fs).

[Jakub Jermář]

Here's the console log:

bash-4.4$ `tools/ew.py -d` -serial stdio
Program loader at 0xffff8000003c0000
RAM disk at 0x0000000002ad000 (size 25165824 bytes)
Kernel console ready (press any key to activate)
0init: HelenOS init
loc: HelenOS Location Service
rd: HelenOS RAM disk server
rd: Found RAM disk at 0x00000000002ad000, 25165824 bytes
vfs: HelenOS VFS slogger: HelenOS Logging Service
ext4fs: HelenOS ext4 fins: HelenOS IPC Naming Service
ns: Accepting connections
loc: Accepting connections
logger: Accepting connections
rd: Accepting connections
erver
vfs: Accepting connections
le system server
ext4fs: Accepting connections
init: Root file system mounted on / (ext4fs at bd/initrd)
init: Starting /srv/tmpfs
tmpfs: HelenOS TMPFS file system server
tmpfs: Accepting connections
init: Starting /srv/exfat
exfat: HelenOS exFAT file system server
exfat: Accepting connections
init: Starting /srv/fat
fat: HelenOS FAT file system server
fat: Accepting connections
init: Starting /srv/cdfs
cdfs: HelenOS cdfs file system server
cdfs: Accepting connections
init: Starting /srv/mfs
mfs: HelenOS Minix file system server
mfs: Accepting connections
init: Starting /srv/klog
[kernel/arch] warn: MADT: Skipping L_APIC_NMI entry (type=4)
init: Starting /srv/locfs
[kernel/arch] note: 0xffffffff800f5b60: MPS Floating Pointer Structure
[kernel/other] note: Program loader at 0xffff8000003c0000
[kernel/other] note: RAM disk at 0x00000000002ad000 (size 25165824 bytes)
locfs: HelenOS Device Filesystem
locfs: Accepting connections
init: Starting /srv/taskmon
taskmon: Task Monitoring Service
init: Location service file system mounted on /loc (locfs)
init: Temporary file system mounted on /tmp (tmpfs)
init: Starting /srv/devman
devman: HelenOS Device Manager
devman: Accepting connections.
root: HelenOS root device driver
init: Unable to stat /srv/s3c24xx_uart
[devman] note: The `roo' driver was successfully registered as running.
tivirt: HelenOS virtual devices root driver
p[devman] note: The `virt' driver was successfully registered as running.
nit: Unable to stat /srv/s3c24xx_ts
init: Starting /srv/vbd
c: HelenOS PC platform driver
[virt] note: Registered child device `kfb'
vbd: Virtual Block Device service
[devman] note: The `pc' driver was successfully registered as running.
vbd: Accepting connections.
init: Starting /srv/volsrv
volsrv: Volume service
kfb: HelenOvolsrv: Accepting connections.S kernel framebuffer driver
[devman] note: The `kfb' driver was successfully registered as running.
init: Starting /srv/loopip
loopip: HelenOS loopback IP link provider
pciintel: HelenOS PCI bus driver (Intel method 1).

loopip: Accepting connections.
[devman] note: The `pciintel' driver was successfully registered as running.init: Starting /srv/ethip
ethip: HelenOS IP over Ethernet service
[devman] note: Function `/virt/kfb/vsl0' added to categor
 `visualizer'.ykfb: Accepting connections
[devman] error: No driver found for device `/hw/pci0/00:00.0'.
[devman] error: No driver found for device `/hw/pci0/00:01.1'.
[pciintel] note: Function 00:01.2 uses irq b.
isa: HelenOS ISA bus driver
uhci: HelenOS UHCI driver.
[devman] note: The `uhci driver was successfully registered as running.
'[pciintel] n
te: Function 00:01.3 uses irq 9.
o[devman] note: The `isa' driver was successfully registered as running.ethip: Accepting connections.
init: Starting /srv/inetsrv
inetsrv: HelenOS Internet Protocol service

inetsrv: Accepting connections.[devman] note: Function `/hw/pci0/00:01.2/ctl' added to category `usbhc'.
[devman] error: No driver found for device `/hw/p
ci0/00:01.3'.
init: Starting /srv/tcp
[devman] error: No driver found for device `/hw/pci0/00:02.0'.
[pciintel] note: Function 00:03.0 uses irq b.
[pciintel] note: Function 00:04.0 uses irq b.
[isa] note: Added mem range (addr=0x20, size=0x2) to functioni8259
tcp: TCP (Transmission Cone1k: HelenOS E1000 [isa] note: Added mem range (addr=0xa0, size=0x2) to functiotn i8259
rol Protocol) network module
 network adapter driver[devman] note: The `xhci' driver was successfully registered as running.
[isa] note: Added mem range (addr=0xfec00000, size=0x14) to function apictcp: Accepting connections.
init: Starting /srv/udp
[devman] note: Function `/hw/pci0/00:04.0/ctl' added to category`usbhc'.
i8259: i8259 Interrupt Controller driver
udp: UDP (User Datagram Protocol) service
 [isa] note: Added irq 0x4 to function com1

[isa] note: Added io range (addr=0x3f8, size=0x8) to unction com1
udp: Accepting connections.
init: Starting /srv/dnsrsrv
f[devman] note: The `i8259' driver was successfully registered as running.
dnsres: DNS Resolution Service[isa] note: Added irq 0x3 to function cm2
apic: APIC driver
ns8250: HelenOS serial port driver

o[pciintel] note: Function 00:
5.0 uses irq a.0[isa] note: Added io range (addr=0x2f8, size=0x8) to function com2
[devman] note: The `apic' driver was successfully registered as running.
[devman] note: The `e1k' driver was successfully registered as running.
[devman] note: Function `/hw/pci0/00:01.0/i8259/a' added to category `irc'.
dnsres: Accepting connections.
init: Starting /srv/dhcp
dhcp: DHCP Service
[isa] note: Added irq 0x1 to function i8042
[isa] note: Added irq 0xc to function i8042
[isa] note: Added io range (addr=0x60, size=0x5) to function i8042
[isa] note: Added irq 0x5 to function ne2k
[isa] note: Added io range (addr=0x300, sizd=0x20) to function ne2k
hcp: Accepting connections.i8042: HelenOS PS/2 driver.
hdaudio: High Definition Audio driver
eapic: No APIC found


init: Starting /srv/nconfsrv
nconfsrv: HelenOS Network configuration service
[nconfsrv] note: Found IP link '31'
[devman] note: The `i8042' driver was successfully registered as running.
[xhci] note: Connected state changed on port 1.
[devman] note: The `hdaudio' driver was successfully registered as running.
[nconfsrv] note: Configure link net/loopback
[xhci] note: Connected state changed on port 2.
[isa] note: Added io range (addr=0x220, size=0x20) to function sb16
[devman] note: The `ns8250' driver was successfully registered as running.
[xhci] note: Connected state changed on port 3.
[isa] note: Added io range (addr=0x330, size=0x2) to function sb16
[devman] note: Function `/hw/pci0/00:03.0/port0' added to category `nic'.
[xhci] note: Connected state changed on port 4.
[isa] note: Added irq 0x5 to function sb16
[xhci] note: Connected state changed on port 5.
[isa] note: Added dma 0x1 to function sb16
[xhci] note: Connected state changed on port 6.
n[isa] note: Added dma 0x5 to function sb16
hdaudio] note: hda_dev_add()nconfsrv: Accepting connections.
init: Starting /srv/clipboard
[[nconfsrv] note: Found IP link '46'

e2k: HelenOS NE 2000 network adapter driver
[xhci] note: Connectd state changed on port 7.
clipboard: HelenOS clipboard service
clipboard: Accepting connections
init: Starting /srv/remconse[uhci] note: Controlling new `uhci' device `00:01.2'.

[nconfsrv] note: Configure link net/eth1
usbhub: HelenOS USB hub drive[devman] note: The `ne2k' driver was successfully registered as running.r.

[ns8250] note: Device com1 was assigned irq = 0x4.
[hdaudio] note: create parent sess
[xhci] note: Connected state changed on port 8.
[isa] note: Added io range (addr=0x70, size=0x2) to function cmos-rtc
[ns8250] note: Device com1 was assigned I/O address = 0x0x3f8.
[xhci] note: Controlling new `xhci' device `00:04.0'.
remcons: HelenOS Remote console service
[devman] note: The `usbhub' driver was sccessfully registered as running.
init: Starting /sru[hdaudio] note: get HW res list
[hdaudio] note: hda reg base: febf4000
[i8042] note: Controlling 'i8042' (44).
[isa] note: Added io range (addr=0x1f0, size=0x8) to functvion ata-c1
xtkbd: HelenOS XT keyboard driver.
sb16: HelenOS SB16 audio driver.
/input
input: HelenOS input service
input: Accepting connections
init: Starting /srv/output
output: HelenOS output service
output: Accepting connections
init: Starting /srv/hound
hound: HelenOS sound ser[hdaudio] note: enable PIO
[isa] note: Added io range (addr=0x3f0, size=0x8) to function ata-c1
[udp] note: udp_assoc_set_nolocal_srv()
[devman] note: Function `/hw/pci0/00:01.0/com1/a' added to category `serial'.
[hdaudio] note: IRQs: 1
[ns8250] note: Device com1 successfully initialized.ps2mouse: HelenOS ps/2 mouse driver.
cmos-rtc: HelenOS RTCvice

[devman] note: The `xtkbd' driver was successfully  registered as running.
driver
[hdaudio] note: interrupt no: 10
[udp] note: Setting nolocal to true
[devman] note: The `sb16' driver was successfully registered as running.
[hound] note: Running with service id 53
[hdaudio] note: range0.base=4273946624
[hdaudio] note: HDA version 1.0
[hdaudio] note: reg 0xe STATESTS = 0x1
[hdaudio] note: after clearing reg 0xe STATESTS = 0x0init: Starting /srv/compositor

[isa] note: Added io range (addr=0x170, size=0x8) to function ata-c2
[devman] note: The `ps2mouse' driver was successfully registered as running.
[usbhub] note: (0x000000000042bc10): Power switching not supported, ports always powered.
[dhcp] note: dhcp_recv_ms()
compositor: HelenOS Compositor server
g[hdaudio] note: Taking controller out of reset.
[isa] note: Added io range (addr=0x370, size=0x8) to function ata-c2
[devman] note: The `cmos-rtc' driver was successfully registered as running.
[hdaudio] note: gctl=0x1
[hdaudio] note: Controller is out of reset.
[dhcp] note: dhcp_recv_msg() - call recv_cb
[hdaudio] note: Read GCAPata_bd: HelenOS ATA(PI) device driver

[ns8250] note: Device com2 was assigned irq = 0x3.
[hdaudio] note: GCAP: 0x4401 (64OK=1)
[ns8250] note: Device com2 was assigned I/O address = 0x0x2f8.
[hdaudio] note: iss: 4, oss: 4, bss: 0
[usbhub] note: Controlling full-speed hub 'roothub' (0x00000000042bc10: 2 ports).
ucompositor: Accepting connections
init: Spawning /app/barber comp:0/winreg
[sb16] note: PIO registers at 0x0000000000000220 accessible.
0sbmid: USB multi interface device drive[devman] note: The `ata_bd' driver was successfully registered as running.
[hdaudio] note: STATESTS = 0x0
[isa] note: Added io range (addr=0x1e8, size=0x8) to function ata-c3
[hdaudio] note: intctl (0x20):= 0xc0000000
r.
 [isa] note: Added io range (addr=0x3e8, size=0x8) to function ata-c3
[sb16] error: Invalid DSP reset response: ff.
[cmos-rtc] note: Device cmos-rtc was assigned I/O address 0x70
[hdaudio] note: hda_corb_init()
input: Connected keyboard device 'devices/\hw\pci0\00:01.0\i8042\ps2a\kbd'
init: Spawning /app/vlaunch comp:0/winreg
init: Spawning /app/vterm comp:0/winreg
init: Starting /srv/console
console: HelenOS Console service
console: Accepting connections
init: Spawning /app/getterm term/vc0 /loc --msg --wait -- /app/bdsh
init: Spawning /app/getterm term/vc1 /loc --wait -- /app/bdsh
init: Spawning /app/getterm term/vc2 /loc --wait -- /app/bdsh
init: Spawning /app/getterm term/vc3 /loc --wait -- /app/bdsh
init: Spawning /app/getterm term/vc4 /loc --wait -- /app/bdsh
init: Spawning /app/getterm term/vc5 /loc --wait -- /app/bdsh
[dhcp] note: net/eth1: dhcpsrv_request_timeout
[sb16] error: Failed to initialize SB DSP: [EIO]Input/output error.
[devman] note: Function `/hw/pci0/00:01.0/i8042/ps2a/kbd' added to category `keyboard'.
[hdaudio] note: Setting CORB Size register to 0x42
[sb16] error: Failed to init sb16 driver: [EIO]Input/output error.
[xtkbd] note: Controlling 'ps2a' (53).
[devman] note: The `usbmid' driver was successfully registered as running.
[hdaudio] note: Set CORB base registers
[ata_bd] note: I/O address 0x00000000000001f0/0x00000000000003f0
[isa] note: Added io range (addr=0x168, size=0x8) to function ata-c4
[ata_bd] note: Identify drive 0...
[hdaudio] note: Reset CORB Read/Write pointers
[devman] note: Function `/hw/pci0/00:01.0/i8042/ps2b/mouse' added to category `mouse'.
input: Connected mouse device 'devices/\hw\pci0\00:01.0\i8042\ps2b\mouse'
[dhcp] note: dhcp_recv_msg()
[ata_bd] note: ATA register-only device found.
[hdaudio] note: CORBctl (0x4c) = 0x2
[isa] note: Added io range (addr=0x368, size=0x8) to function ata-c4
[ata_bd] note: QEMU HARDDISK: LBA-48 4134 blocks 2 MB.
[hdaudio] note: CORB initialized
[ps2mouse] note: Enabled IntelliMouse extensions
[dhcp] note: dhcp_recv_msg() - call recv_cb
[ata_bd] note: Identify drive 1...
[hdaudio] note: hda_rirb_init()
[devman] note: Function `/hw/pci0/00:01.0/cmos-rtc/a' added to category `clock'.
[hdaudio] note: Setting RIRB Size register to 0x42
[cmos-rtc] note: Device cmos-rtc successfully initialized
[isa] note: Finished enumerating legacy functions
[hdaudio] note: Set RIRB base registers
[hdaudio] note: Reset RIRB Write pointer
[hdaudio] note: RIRBctl (0x5c) = 0x2
[hdaudio] note: RIRB initialized
[ps2mouse] note: Enabled 4th and 5th button.
[hdaudio] note: call hda_codec_init()
[ps2mouse] note: Controlling 'ps2b' (56).
[usbmid] note: Taking care of new MID `usb1-hs'.
[dhcp] note: net/eth1: Successfully configured.
[hdaudio] note: hda_get_subnc -> EOK
[hdaudio] note: sfg=1 nfg=1
[hdaudio] note: Enumerate FG 1
[dhcp] note: dhcp_recv_msg()
[dhcp] note: dhcp_recv_msg() - call recv_cb
[hdaudio] note: hda_get_fgrp_type -> EOK
[hdaudio] note: unsol: 0, grptype: 1
[usbmid] note: Creating child for interface 0 (HID).
[hdaudio] note: GPIO: wake=0 unsol=0 gpis=0 gpos=0 gpios=0
[hdaudio] note: aw 1 is power control-capable
[hdaudio] note: aw 1: power state = 0x0
[hdaudio] note: hda_get_subnc -> EOK
[hdaudio] note: saw=2 baw=4
[hdaudio] note: aw 2: type=0x0 caps=0x1d
[hdaudio] note: Output widget 2: rates=0x201fc formats=0x1
[hdaudio] note: out amp caps 0x80034a4a (offset=0x4a)
[hdaudio] note: gain/mute: L:0x4a R:0x4a
[hdaudio] note: aw 3: type=0x4 caps=0x400101
[hdaudio] note: Connections for widget 3:
[hdaudio] note: <- 2 *** current *** 
[hdaudio] note: aw 3: PIN cdfgef=0x4010
[hdaudio] note: aw 3 : PIN caps=0x10
[hdaudio] note: PIN 3 will enable output
[hdaudio] note: SettingPIN 3 ctl to 0x40
usbhid: HelenOS USB HID driver.
 [devman] note: The `usbhid' driver was successfully registered as running.
[hdaudio] note: PIN 3 ctl reads as 0x40
[hdaudio] note: aw 4: type=0x1 caps=0x10011b
[hdaudio] note: Connections for widget 4:
[hdaudio] note: <- 5 *** current *** 
[hdaudio] note: Selected input widget 4
[hdaudio] note: Input widget 4: rates=0x201fc formats=0x1
[hdaudio] note: in amp caps 0x0 (offset=0x0)
[hdaudio] note: in:0 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:1 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:2 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:3 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:4 gain/mute: L:0x0 R:0x0
[devman] note: Function `/hw/pci0/00:04.0/usb1-hs/HID0/mouse' added to category `mouse'.
input: Connected mouse device 'devices/\hw\pci0\00:04.0\usb1-hs\HID0\mouse'
[usbhid] note: HID device `HID0' ready.
[hdaudio] note: in:5 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:6 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:7 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:8 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:9 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:10 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:11 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:12 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:13 gain/mute: L:0x0 R:0x0
[hdaudio] note: in:14 gain/mute: L:0x0 R:0x0
[hdaudio] note: aw 5: type=0x4 caps=0x400001
[hdaudio] note: Connections for widget 5:
[hdaudio] note: aw 5: PIN cdfgef=0x805020
[hdaudio] note: aw 5 : PIN caps=0x20
[hdaudio] note: PIN 5 will enable input
[hdaudio] note: Setting PIN 5 ctl to 0x20
[hdaudio] note: PIN 5 ctl reads as 0x20
[hdaudio] note: corbwp=76, corbrp=76
[hdaudio] note: corbctl=0x2, corbsts=0x0
[hdaudio] note: rirbwp=0x4c, soft-rirbrp=0x4c
[hdaudio] note: solrb_wp=0x4c, solrb_rp=0x4c
[hdaudio] note: Codec OK
[hdaudio] note: intsts=0x0
[hdaudio] note: sdesc[4].sts=0x20
[hdaudio] note: create function
[devman] note: Function `/hw/pci0/00:05.0/pcm' added to category `audio-pcm'.
[hound] note: Added new device: 'devices/\hw\pci0\00:05.0\pcm'
[hdaudio] note: hda_query_cap(0)
[hdaudio] note: hda_query_cap(1)
[ata_bd] note: Not found.
[devman] note: Function `/hw/pci0/00:01.0/ata-c1/d0' added to category `disk'.
[vbd] note: Found disk '74'
[ata_bd] note: I/O address 0x0000000000000170/0x0000000000000370
[ata_bd] note: Identify drive 0...
[ata_bd] note: QEMU DVD-ROM: PACKET 14547 blocks 7 MB.
[ata_bd] note: Identify drive 1...
[vbd] note: Recognized disk label. Adding partitions.
[volsrv] note: Found partition '75'
[volsrv] note: Probe partition devices/\hw\pci0\00:01.0\ata-c1\d0p0
[volsrv] note: Found fat, label ''
[volsrv] note: Added partition 75
[ata_bd] note: Not found.
[devman] note: Function `/hw/pci0/00:01.0/ata-c2/d0' added to category `disk'.
[vbd] note: Found disk '76'
[ata_bd] note: I/O address 0x00000000000001e8/0x00000000000003e8
[ata_bd] note: Identify drive 0...
[vbd] note: Recognized disk label. Adding partitions.
[volsrv] note: Found partition '77'
[volsrv] note: Probe partition devices/\hw\pci0\00:01.0\ata-c2\d0p0
[volsrv] note: Found cdfs, label 'HelenOS-CD'
[volsrv] note: Added partition 77
[ata_bd] note: Not found.
[ata_bd] note: Identify drive 1...
[ata_bd] note: Not found.
[ata_bd] warn: No disks detected.
[ata_bd] error: Failed initializing ATA controller.
[ata_bd] note: I/O address 0x0000000000000168/0x0000000000000368
[ata_bd] note: Identify drive 0...
[ata_bd] note: Not found.
[ata_bd] note: Identify drive 1...
[ata_bd] note: Not found.
[ata_bd] warn: No disks detected.
[ata_bd] error: Failed initializing ATA controller.
Assertion failed (!head->free) in file "generic/malloc.c", line 1002.
taskmon: Task 9 fault in thread 0xffffffff81dac000.
taskmon: Executing /app/taskdump -t 9
Task Dump Utility
Dumping task 'tmpfs' (task ID 9).
failed opening file '/app/tmpfs': [ENOENT]No such entry
Loaded symbol table from /srv/tmpfs

Threads:
 [1] hash: 0xffffffff81dac000
Thread 0xffffffff81dac000: PC = 0x000000000040d848 (async_manager_fibril+280). FP = 0x0000000000419fc0
  0x0000000000419fc0: 0x000000000040d848 (async_manager_fibril+280)
  0x0000000000419ff0: 0x0000000000403ea1 (fibril_main+33)

Address space areas:
 [1] flags: R-XC base: 0x0000000000400000 size: 86016
 [2] flags: RW-C base: 0x0000000000415000 size: 4096
 [3] flags: RW-C base: 0x0000000000416000 size: 8192
 [4] flags: RW-C base: 0x0000000000419000 size: 4096
 [5] flags: RW-C base: 0x000000000041b000 size: 12288
 [6] flags: RW-C base: 0x000000000041f000 size: 1048576
 [7] flags: R--C base: 0x0000000000520000 size: 65536
 [8] flags: RW-C base: 0x0000000000531000 size: 1048576
 [9] flags: R-XC base: 0x0000000070000000 size: 69632
 [10] flags: RW-C base: 0x0000000070011000 size: 12288
 [11] flags: RW-C base: 0x0000000070014000 size: 8192
 [12] flags: RW-C base: 0x0000000070017000 size: 4096
 [13] flags: RW-C base: 0x0000000070019000 size: 4096
 [14] flags: RW-C base: 0x000000007001b000 size: 1048576
 [15] flags: RW-C base: 0x00007ffffff00000 size: 1048576

Fibril 0x0000000000417d00:
  0x0000000000419ec0: 0x0000000000410581 (context_swap+17)
  0x0000000000419ef0: 0x0000000000404528 (fibril_switch+392)
  0x0000000000419fc0: 0x000000000040d77a (async_manager_fibril+74)
  0x0000000000419ff0: 0x0000000000403ea1 (fibril_main+33)
Fibril 0x000000000041d020:
  0x000000000051ec80: 0x0000000000410581 (context_swap+17)
  0x000000000051ecb0: 0x0000000000404528 (fibril_switch+392)
  0x000000000051ed10: 0x000000000040dff6 (async_get_call_timeout+134)
  0x000000000051ef80: 0x00000000004010de (vfs_connection+46)
  0x000000000051efc0: 0x000000000040d34d (connection_fibril+173)
  0x000000000051eff0: 0x0000000000403ea1 (fibril_main+33)
Fibril 0x000000000041d100:
  0x0000000000630c80: 0x0000000000410581 (context_swap+17)
  0x0000000000630cb0: 0x0000000000404528 (fibril_switch+392)

######> Kernel panic on cpu0 due to a failed assertion: <######
answer_preprocess() at generic/src/ipc/sysipc.c:174:
answer->active

THE=0xffffffff81dde000: pe=1 thread=0xffffffff81ddd000 task=0xffffffff81dd0810 cpu=0xffffffff81da5000 as=0xffffffff81b312f8 magic=0xfacefeed
thread="uinit"
task="init:vfs"
0xffffffff81dded30: generic/src/debug/stacktrace.o:stack_trace()+0x0000000000000016
0xffffffff81ddedd0: generic/src/debug/panic.o:panic_common()+0x00000000000001dd
0xffffffff81ddeeb0: generic/src/ipc/sysipc.o:sys_ipc_answer_fast()+0x0000000000000318
0xffffffff81ddef30: generic/src/syscall/syscall.o:syscall_handler()+0x00000000000000cc
0xffffffff81ddefc0: arch/amd64/src/asm.o:syscall_entry()+0x00000000000000bc
cpu0: halted

[Jakub Jermář]

So there are two issues:

1. tmpfs misbehaves and crashes
2. the kernel panics

The kernel panic can be more easily reproduced like this:

 # killall tmpfs
 # ls /tmp 

[Jakub Jermář]

The kernel panic issue is fixed by commit 931afbc21fb7256372512b67f529ef39acfc8ac8.

[Jakub Jermář]

The tmpfs issue is fixed in ec397203e399886ac45d617da8098ea6ae81f914.