Messages in this thread | | | Date | Tue, 22 Mar 2022 09:08:22 +0100 | From | Peter Zijlstra <> | Subject | Re: linux-next: build warnings after merge of the tip tree |
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On Tue, Mar 22, 2022 at 02:31:36PM +0900, Masami Hiramatsu wrote:
> > Also, I think both should fix regs->ss. > > I'm not sure this part. Since the return trampoline should run in the same > context of the called function, isn't ss same there too?
It creates pt_regs on the stack, so the trampolines do:
push $arch_rethook_trampoline push %rsp pushf sub $24, %rsp /* cs, ip, orig_ax */ push %rdi ... push %r15
That means that if anybody looks at regs->ss, it'll find $arch_rethook_trampoline, which isn't a valid segment descriptor, or am I just really bad at counting today?
I'm thinking you want a copy of __KERNEL_DS in that stack slot, not a function pointer.
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