svn commit: r355784 - in head/sys: compat/linuxkpi/common/src dev/dpaa kern mips/nlm sys

[Jeff Roberson]

On Mon, 16 Dec 2019, Ryan Libby wrote:

> On Mon, Dec 16, 2019 at 7:30 AM Ed Maste <emaste at freebsd.org> wrote:
>>
>> On Sun, 15 Dec 2019 at 16:27, Jeff Roberson <jeff at freebsd.org> wrote:
>>>
>>> Author: jeff
>>> Date: Sun Dec 15 21:26:50 2019
>>> New Revision: 355784
>>> URL: https://svnweb.freebsd.org/changeset/base/355784
>>>
>>> Log:
>>>   schedlock 4/4
>>
>> FYI i386, arm, arm64, riscv fail to boot now, with "panic: invalid count 2"
>>
>> Boot logs:
>> i386: https://ci.freebsd.org/job/FreeBSD-head-i386-test/7797/console
>> arm: https://ci.freebsd.org/hwlab/job/FreeBSD-device-head-beaglebone-test/1317/artifact/device_tests/beaglebone.boot.log
>> arm64: https://ci.freebsd.org/hwlab/job/FreeBSD-device-head-pinea64-test/1194/artifact/device_tests/pinea64.boot.log
>> riscv: https://ci.freebsd.org/hwlab/job/FreeBSD-device-head-pinea64-test/1194/artifact/device_tests/pinea64.boot.log
>>
>> arm64 is:
>>
>> panic: invalid count 2
>> cpuid = 0
>> time = 1
>> KDB: stack backtrace:
>> db_trace_self() at db_trace_self_wrapper+0x28
>> pc = 0xffff0000007359ec  lr = 0xffff000000106744
>> sp = 0xffff000056b063c0  fp = 0xffff000056b065d0
>>
>> db_trace_self_wrapper() at vpanic+0x18c
>> pc = 0xffff000000106744  lr = 0xffff000000408128
>> sp = 0xffff000056b065e0  fp = 0xffff000056b06690
>>
>> vpanic() at panic+0x44
>> pc = 0xffff000000408128  lr = 0xffff000000407ed8
>> sp = 0xffff000056b066a0  fp = 0xffff000056b06720
>>
>> panic() at sched_switch+0x81c
>> pc = 0xffff000000407ed8  lr = 0xffff000000434264
>> sp = 0xffff000056b06730  fp = 0xffff000056b06810
>>
>> sched_switch() at mi_switch+0x170
>> pc = 0xffff000000434264  lr = 0xffff000000413690
>> sp = 0xffff000056b06820  fp = 0xffff000056b06840
>>
>> mi_switch() at cpu_idle+0xc8
>> pc = 0xffff000000413690  lr = 0xffff0000007400a0
>> sp = 0xffff000056b06850  fp = 0xffff000056b06860
>>
>> cpu_idle() at sched_idletd+0x380
>> pc = 0xffff0000007400a0  lr = 0xffff000000436a90
>> sp = 0xffff000056b06870  fp = 0xffff000056b06940
>>
>> sched_idletd() at fork_exit+0x7c
>> pc = 0xffff000000436a90  lr = 0xffff0000003c7ba4
>> sp = 0xffff000056b06950  fp = 0xffff000056b06980
>>
>> fork_exit() at fork_trampoline+0x10
>> pc = 0xffff0000003c7ba4  lr = 0xffff0000007521ac
>> sp = 0xffff000056b06990  fp = 0x0000000000000000
>>
>> KDB: enter: panic
>> [ thread pid 11 tid 100003 ]
>> Stopped at      0
>> db>
>
> It looks like amd64 vs i386, riscv, etc are using different motifs in
> spinlock_exit().  Perhaps we just need to rearrange them to drop the
> spinlock count before critical_exit(), like in amd64.

It took me a moment to see why but I believe you are right.  Interrupts 
being disabled would prevent a local preemption with the flags out of sync 
but critical_exit() might have owepreempt set so we will switch before 
updating the count.

Jeff

>
> Ryan
>