Re: [PATCH] powerpc/970: fix nap return address corruption on async interrupt exit
From: Madhavan Srinivasan <maddy@linux.ibm.com>
Date: 2026-07-30 05:41:48
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On Tue, 07 Jul 2026 22:54:30 +0530, Mukesh Kumar Chaurasiya (IBM) wrote:
On PowerMac G5 (PPC970, CONFIG_PPC_970_NAP) the system panics shortly after boot with symptoms including instruction fetch faults, kernel data access faults, and stack corruption, predominantly on SMP and always somewhere inside softirq processing. The PPC970 idle path works by setting _TLF_NAPPING in the current thread's local flags before entering the MSR_POW nap loop. When any async interrupt wakes the CPU, nap_adjust_return() is expected to detect _TLF_NAPPING, clear it, and rewrite regs->NIP to power4_idle_nap_return so that the interrupt returns cleanly to the caller of power4_idle_nap() rather than back into the nap spin loop. [...]
Applied to powerpc/fixes.
[1/1] powerpc/970: fix nap return address corruption on async interrupt exit
https://git.kernel.org/powerpc/c/bddf7540099bf653eaea339e886add6f62555cf3
cheers