Hi,
On 03-07-16 16:04, Karsten Merker wrote:
Hello,
I am experiencing a kernel panic on shutdown due to killing init
on various Allwinner A20-based systems (e.g. Cubietruck and
Lime2). Killing init in turn appears to be a result of a locked
i2c bus. This only happens on shutdown, but not on reboot. The
problem exists already for quite some time but I hadn't found
enough time to debug this properly before.
Follwing is a log from shutting down a Cubietruck, running kernel
4.6.2 (Debian/sid kernel package) and u-boot v2016.07-rc3 (plain
upstream build):
systemd-shutdown[1]: Sending SIGTERM to remaining processes...
systemd-journald[522]: Received SIGTERM from PID 1 (systemd-shutdow).
systemd-shutdown[1]: Sending SIGKILL to remaining processes...
systemd-shutdown[1]: Unmounting file systems.
systemd-shutdown[1]: Remounting '/' read-only with options
'errors=remount-ro,data=ordered'.
EXT4-fs (sda2): re-mounted. Opts: errors=remount-ro,data=ordered
systemd-shutdown[1]: Remounting '/' read-only with options
'errors=remount-ro,data=ordered'.
EXT4-fs (sda2): re-mounted. Opts: errors=remount-ro,data=ordered
systemd-shutdown[1]: All filesystems unmounted.
systemd-shutdown[1]: Deactivating swaps.
systemd-shutdown[1]: All swaps deactivated.
systemd-shutdown[1]: Detaching loop devices.
systemd-shutdown[1]: All loop devices detached.
systemd-shutdown[1]: Detaching DM devices.
systemd-shutdown[1]: All DM devices detached.
systemd-shutdown[1]: Powering off.
kvm: exiting hardware virtualization
sd 0:0:0:0: [sda] Synchronizing SCSI cache
sd 0:0:0:0: [sda] Stopping disk
musb-hdrc musb-hdrc.1.auto: remove, state 4
usb usb3: USB disconnect, device number 1
musb-hdrc musb-hdrc.1.auto: USB bus 3 deregistered
reboot: Power down
i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0
Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000
CPU: 0 PID: 1 Comm: systemd-shutdow Tainted: G E
4.6.0-1-armmp-lpae #1 Debian 4.6.2-2
Hardware name: Allwinner sun7i (A20) Family
[<c022efdc>] (unwind_backtrace) from [<c02290c8>] (show_stack+0x20/0x24)
[<c02290c8>] (show_stack) from [<c051a66c>] (dump_stack+0x98/0xac)
[<c051a66c>] (dump_stack) from [<c0374004>] (panic+0xfc/0x28c)
[<c0374004>] (panic) from [<c026bcb8>] (complete_and_exit+0x0/0x2c)
[<c026bcb8>] (complete_and_exit) from [<c028ac44>] (SyS_reboot+0x1c8/0x238)
[<c028ac44>] (SyS_reboot) from [<c0224aa0>] (ret_fast_syscall+0x0/0x34)
---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000
What makes this kind of strange is that it appears to happen
depending on the u-boot version I use. Plain upstream
v2016.03, v2016.05 and v2016.07rc3 all cause a crash, while
the Debian version 2016.03+dfsg1-6 works without problems:
systemd-shutdown[1]: Sending SIGTERM to remaining processes...
systemd-journald[534]: Received SIGTERM from PID 1 (systemd-shutdow).
systemd-shutdown[1]: Sending SIGKILL to remaining processes...
systemd-shutdown[1]: Unmounting file systems.
systemd-shutdown[1]: Remounting '/' read-only with options
'errors=remount-ro,data=ordered'.
EXT4-fs (sda2): re-mounted. Opts: errors=remount-ro,data=ordered
systemd-shutdown[1]: Remounting '/' read-only with options
'errors=remount-ro,data=ordered'.
EXT4-fs (sda2): re-mounted. Opts: errors=remount-ro,data=ordered
systemd-shutdown[1]: All filesystems unmounted.
systemd-shutdown[1]: Deactivating swaps.
systemd-shutdown[1]: All swaps deactivated.
systemd-shutdown[1]: Detaching loop devices.
systemd-shutdown[1]: All loop devices detached.
systemd-shutdown[1]: Detaching DM devices.
systemd-shutdown[1]: All DM devices detached.
systemd-shutdown[1]: Powering off.
kvm: exiting hardware virtualization
sd 0:0:0:0: [sda] Synchronizing SCSI cache
sd 0:0:0:0: [sda] Stopping disk
musb-hdrc musb-hdrc.1.auto: remove, state 4
usb usb2: USB disconnect, device number 1
musb-hdrc musb-hdrc.1.auto: USB bus 2 deregistered
reboot: Power down
The only possibly relevant change in the Debian build compared to
upstream v2016.03 that I can see is cherry-picking commit
affa020559bca31d6531e19cb1f009c22705a73d from upstream u-boot
v2016.05 (which addresses an i2c-related hang on Lime/Lime2
boards by setting certain regulator voltages, but doesn't touch
e.g. the Cubietruck at all):
https://anonscm.debian.org/cgit/collab-maint/u-boot.git/tree/debian/patches/upstream/sunxi/0002-sunxi-Enable-LDO3-and-LDO4-at-2.8V-on-OLinuxIno-Lime.patch
I have cross-checked that by building upstream v2016.03 with this
patch on top - no panic happens, while with plain upstream
v2016.03 the system does panic.
So on a Cubietruck, plain upstream v2016.03 results in a panic;
plain upstream v2016.03 with the aforementioned commit
cherry-picked on top works fine, even though the commit is
completely irrelevant to the Cubietruck. Plain upstream v2016.05,
which contains this commit, crashes again, as does v2016.07-rc3.
Can anybody reproduce this problem or does anybody have an idea
what could be happening here?
You're likely being hit by the irq affinity problem I've been
discussing upstream. Try disabling irqbalanced, it seems that the
latest version ties the i2c controller irq to cpu-1, and before
power down cpu-1 is shutdown leaving only cpu-0 resulting in the
interrupts going nowhere and the bus seeming to be stuck to the
kernel.
Regards,
Hans
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