Re: [Xen-devel] [PATCH] xen/arm: Fix rtds scheduler for arm

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Fri, 2015-01-30 at 18:19 +0200, Denys Drozdov wrote:

> since context_save executed right from IRQ level. The arm interrupt
> handling differs from x86. ARM is handling  context_saved with IRQ
> disabled in CPSR, though x86 has IRQs on. Thus it is failing on ASSERT
> inside spin_lock_irq when running on ARM. I guess it should work on
> x86, so this issue is ARM platform specific.

FWIW I was waiting for it to happen to a xen-unstable run but the latest
osstest gate run at
http://www.chiark.greenend.org.uk/~xensrcts/logs/33915/ which included
Dario's patches to rationalize the schedulr tests vs. archs also
resulted in a similar sounding failure on credit2:
http://www.chiark.greenend.org.uk/~xensrcts/logs/33915/test-armhf-armhf-xl-credit2/info.html
http://www.chiark.greenend.org.uk/~xensrcts/logs/33915/test-armhf-armhf-xl-credit2/serial-marilith-n5.txt

        [Thu Jan 29 13:29:28 2015](XEN) Assertion 'local_irq_is_enabled()' 
failed at spinlock.c:137
        [Thu Jan 29 13:29:28 2015](XEN) ----[ Xen-4.6-unstable  arm32  debug=y  
Not tainted ]----
        [Thu Jan 29 13:29:28 2015](XEN) CPU:    0
        [Thu Jan 29 13:29:28 2015](XEN) PC:     00229734 
_spin_lock_irq+0x18/0x94
        [Thu Jan 29 13:29:28 2015](XEN) CPSR:   200000da MODE:Hypervisor
        [Thu Jan 29 13:29:28 2015](XEN)      R0: 4000823c R1: 00000000 R2: 
02faf080 R3: 600000da
        [Thu Jan 29 13:29:28 2015](XEN)      R4: 4000823c R5: 4000d000 R6: 
4000823c R7: 002ee020
        [Thu Jan 29 13:29:28 2015](XEN)      R8: 4000f218 R9: 00000000 
R10:0026fe08 R11:7ffcfefc R12:00000002
        [Thu Jan 29 13:29:28 2015](XEN) HYP: SP: 7ffcfeec LR: 0021f34c
        [Thu Jan 29 13:29:28 2015](XEN) 
        [Thu Jan 29 13:29:28 2015](XEN)   VTCR_EL2: 80003558
        [Thu Jan 29 13:29:28 2015](XEN)  VTTBR_EL2: 00010002b9ffc000
        [Thu Jan 29 13:29:28 2015](XEN) 
        [Thu Jan 29 13:29:28 2015](XEN)  SCTLR_EL2: 30cd187f
        [Thu Jan 29 13:29:28 2015](XEN)    HCR_EL2: 000000000038643f
        [Thu Jan 29 13:29:28 2015](XEN)  TTBR0_EL2: 00000000ff6e8000
        [Thu Jan 29 13:29:28 2015](XEN) 
        [Thu Jan 29 13:29:28 2015](XEN)    ESR_EL2: 00000000
        [Thu Jan 29 13:29:28 2015](XEN)  HPFAR_EL2: 0000000000000000
        [Thu Jan 29 13:29:28 2015](XEN)      HDFAR: 00000000
        [Thu Jan 29 13:29:28 2015](XEN)      HIFAR: 00000000
        [Thu Jan 29 13:29:28 2015](XEN) 
        [Thu Jan 29 13:29:28 2015](XEN) Xen stack trace from sp=7ffcfeec:
        [Thu Jan 29 13:29:28 2015](XEN)    0024d068 00000000 002f0328 7ffcff2c 
0021f34c 00000000 00000000 6591e5c1
        [Thu Jan 29 13:29:28 2015](XEN)    00000000 4000d000 4000d000 00000000 
00000000 00000000 00000000 7ffcff3c
        [Thu Jan 29 13:29:28 2015](XEN)    002285dc 00007fff 00000000 7ffcff4c 
00242614 00000000 00000000 7ffcff54
        [Thu Jan 29 13:29:28 2015](XEN)    002427c8 00000000 00242b6c 00000000 
ffffffff 28000000 00000000 00000000
        [Thu Jan 29 13:29:28 2015](XEN)    00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000
        [Thu Jan 29 13:29:28 2015](XEN)    00000000 00000000 27a00000 000001d3 
00000000 00000000 00000000 00000000
        [Thu Jan 29 13:29:28 2015](XEN)    00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000
        [Thu Jan 29 13:29:28 2015](XEN)    00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000
        [Thu Jan 29 13:29:28 2015](XEN)    00000000 00000000 00000000 00000000 
00000000
        [Thu Jan 29 13:29:28 2015](XEN) Xen call trace:
        [Thu Jan 29 13:29:28 2015](XEN)    [<00229734>] 
_spin_lock_irq+0x18/0x94 (PC)
        [Thu Jan 29 13:29:28 2015](XEN)    [<0021f34c>] 
csched2_context_saved+0x44/0x18c (LR)
        [Thu Jan 29 13:29:28 2015](XEN)    [<0021f34c>] 
csched2_context_saved+0x44/0x18c
        [Thu Jan 29 13:29:28 2015](XEN)    [<002285dc>] context_saved+0x58/0x80
        [Thu Jan 29 13:29:28 2015](XEN)    [<00242614>] 
schedule_tail+0x148/0x2f0
        [Thu Jan 29 13:29:28 2015](XEN)    [<002427c8>] 
continue_new_vcpu+0xc/0x70
        [Thu Jan 29 13:29:28 2015](XEN)    [<00242b6c>] context_switch+0x74/0x7c
        [Thu Jan 29 13:29:28 2015](XEN) 
        [Thu Jan 29 13:29:28 2015](XEN) 
        [Thu Jan 29 13:29:28 2015](XEN) ****************************************
        [Thu Jan 29 13:29:28 2015](XEN) Panic on CPU 0:
        [Thu Jan 29 13:29:28 2015](XEN) Assertion 'local_irq_is_enabled()' 
failed at spinlock.c:137
        [Thu Jan 29 13:29:28 2015](XEN) ****************************************
        
I didn't have a chance yet to think about whether the ARM ctxt switch or
the scheduler(s) are in the wrong here...

Ian.



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