On 24.10.2016 21:55, Helge Deller wrote:
> Since kernel 3.9 we re-enable interrupts quite late due to commit c207a76bf15
> ("parisc: only re-enable interrupts if we need to schedule or deliver signals
> when returning to userspace"). At that time the parisc kernel had no dedicated
> IRQ stack, and this commit prevented kernel stack overflows.
>
> But since commit 200c880420a ("parisc: implement irq stacks") we now have an
> IRQ stack, so we may be safe now. And when CONFIG_DEBUG_STACKOVERFLOW=y is
> enabled, we can even check at runtime for overflows.
I've just seen a kernel panic, which I think to be triggered by this patch:
postfix: See http://www.postfix.org/COMPATIBILITY_README.html for details
postfix: To disable backwards compatibility use "postconf compatibility_level=2" and "postfix reload"
.
[ 64.880230] stackcheck: swapper/1 will most likely overflow irq stack (sp:413abc7a40, stk bottom-top:413abc4028-413abc8028)
[ 64.881281] Kernel panic - not syncing: low stack detected by irq handler - check messages
[ 64.881281]
[ 64.881281] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.9.0-rc6-64bit+ #564
[ 64.881281] Backtrace:
[ 64.881281] [<000000004021a7d8>] show_stack+0x68/0x80
[ 64.881281] [<00000000407fcb8c>] dump_stack+0xec/0x168
[ 64.881281] [<000000004024c364>] panic+0x204/0x500
[ 64.881281] [<000000004021ddac>] do_cpu_irq_mask+0x3c4/0x480
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281]
[ 64.881281] _______________________________
[ 64.881281] < Your System ate a SPARC! Gah! >
[ 64.881281] -------------------------------
[ 64.881281] \ ^__^
[ 64.881281] (__)\ )\/\
[ 64.881281] U ||----w |
[ 64.881281] || ||
[ 64.881281] swapper/1 (pid 0): Protection id trap (code 7)
[ 64.881281] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.9.0-rc6-64bit+ #564
[ 64.881281] task: 000000007fd0ea90 task.stack: 000000007fd5c000
[ 64.881281]
[ 64.881281] YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
[ 64.881281] PSW: 00001000000001101111110100001110 Not tainted
[ 64.881281] r00-03 000000ff0806fd0e 0000000040d8aca0 0000000140219ebc 000000413abc8070
[ 64.881281] r04-07 0000000040d0b4a0 000000413abc8400 000000413abc8328 000000413abc8078
[ 64.881281] r08-11 000000004021a7d8 000000413abc7fb0 00000000411860d0 000000413abc7a40
[ 64.881281] r12-15 000000007fd5c2c0 0000000000000041 0000000000000041 0000000040d8b4a0
[ 64.881281] r16-19 000000413abc7a40 0000000040d8c4a0 0000000000000004 000000000800000e
[ 64.881281] r20-23 0000000000000001 000000413abc83f0 0000000000000000 0000000000000384
[ 64.881281] r24-27 0000000000000000 000000004080e5d8 000000004036aed0 0000000040d0b4a0
[ 64.881281] r28-31 0000000000000000 000000413abc8a70 000000413abc8400 0000000041145d94
[ 64.881281] sr00-03 00000000003b2800 0000000000000000 0000000000000000 00000000003b2800
[ 64.881281] sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 64.881281]
[ 64.881281] IASQ: 0000000000000001 0000000000000001 IAOQ: 0000000140219ebc 0000000140219ec0
[ 64.881281] IIR: 43ffff40 ISR: 0000000000000000 IOR: 0000000000000000
[ 64.881281] CPU: 1 CR30: 000000007fd5c000 CR31: 9cf8a6e3d01f680f
[ 64.881281] ORIG_R28: 000000413abc8540
[ 64.881281] IAOQ[0]: 0x140219ebc
[ 64.881281] IAOQ[1]: 0x140219ec0
[ 64.881281] RP(r2): 0x140219ebc
[ 64.881281] Backtrace:
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281]
[ 64.881281] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.9.0-rc6-64bit+ #564
[ 64.881281] Backtrace:
[ 64.881281] [<000000004021a7d8>] show_stack+0x68/0x80
[ 64.881281] [<00000000407fcb8c>] dump_stack+0xec/0x168
[ 64.881281] [<000000004021ab08>] die_if_kernel+0x2c0/0x3a8
[ 64.881281] [<000000004021b7fc>] handle_interruption+0x6dc/0xbb0
[ 64.881281] [<0000000040208084>] intr_check_sig+0x0/0x38
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281] [<0000000040208074>] intr_return+0x0/0x10
[ 64.881281]
[ 64.881281] Kernel panic - not syncing: Fatal exception in interrupt
<Cpu1> 78000c6201e00000 a0e008c01100b009 CC_PAT_ENCODED_FIELD_WARNING
<Cpu1> 76000c6801e00000 0000000000000520 CC_PAT_DATA_FIELD_WARNING
<Cpu1> 0300109101e00000 0000000000000000 CC_PROCS_ENTRY_OUT
--
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