On Thu, Jan 16, 2014 at 10:05:32AM -0800, Guenter Roeck wrote: > Hi all, > > I am getting kernel stack overflows with v3.13-rc8 on a system with P2020 CPU. > The kernel is patched for the target, but I don't think that is related. > Stack overflows are in different areas, but always in calls from __do_softirq. > > Crashes happen reliably either during boot or if I put any kind of load > onto the system.
How about the following fix:
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index e47d268727a4..52fffe5616b4 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -61,7 +61,7 @@ _GLOBAL(call_do_irq)
mflr r0
stw r0,4(r1)
lwz r10,THREAD+KSP_LIMIT(r2)
- addi r11,r3,THREAD_INFO_GAP
+ addi r11,r4,THREAD_INFO_GAP
stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r4)
mr r1,r4
stw r10,8(r1)
Thanks,
Kevin
>
> Example:
>
> Kernel stack overflow in process eb3e5a00, r1=eb79df90
> CPU: 0 PID: 2838 Comm: ssh Not tainted 3.13.0-rc8-juniper-00146-g19eca00 #4
> task: eb3e5a00 ti: c0616000 task.ti: ef440000
> NIP: c003a420 LR: c003a410 CTR: c0017518
> REGS: eb79dee0 TRAP: 0901 Not tainted (3.13.0-rc8-juniper-00146-g19eca00)
> MSR: 00029000 <CE,EE,ME> CR: 24008444 XER: 00000000
> GPR00: c003a410 eb79df90 eb3e5a00 00000000 eb05d900 00000001 65d87646 00000000
> GPR08: 00000000 020b8000 00000000 00000000 44008442
> NIP [c003a420] __do_softirq+0x94/0x1ec
> LR [c003a410] __do_softirq+0x84/0x1ec
> Call Trace:
> [eb79df90] [c003a410] __do_softirq+0x84/0x1ec (unreliable)
> [eb79dfe0] [c003a970] irq_exit+0xbc/0xc8
> [eb79dff0] [c000cc1c] call_do_irq+0x24/0x3c
> [ef441f20] [c00046a8] do_IRQ+0x8c/0xf8
> [ef441f40] [c000e7f4] ret_from_except+0x0/0x18
> --- Exception: 501 at 0xfcda524
> LR = 0x10024900
> Instruction dump:
> 7c781b78 3b40000a 3a73b040 543c0024 3a800000 3b3913a0 7ef5bb78 48201bf9
> 5463103a 7d3b182e 7e89b92e 7c008146 <3ba00000> 7e7e9b78 48000014 57fff87f
> Kernel panic - not syncing: kernel stack overflow
> CPU: 0 PID: 2838 Comm: ssh Not tainted 3.13.0-rc8-juniper-00146-g19eca00 #4
> Call Trace:
> Rebooting in 180 seconds..
>
> Reverting the following commit fixes the problem.
>
> cbc9565ee8 "powerpc: Remove ksp_limit on ppc64"
>
> Should I submit a patch reverting this commit, or is there a better way to fix
> the problem on short notice (given that 3.13 is close) ?
>
> Thanks,
> Guenter
> _______________________________________________
> Linuxppc-dev mailing list
> linuxppc-...@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
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