Messages in this thread | | | Date | Fri, 1 Apr 2022 13:45:03 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH] signal/x86: Delay calling signals in atomic |
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On 2022-03-30 13:10:05 [-0500], Eric W. Biederman wrote: > But it looks like if we are coming from userspace then we use the same > stack as any other time we would come from userspace. AKA a stack > that allows the kernel to sleep. > > So I don't see what the problem is that is trying to be fixed.
It is not only the stack. In atomic context / disabled interrupts it is not possible to acquire a spinlock_t (sighand_struct::siglock) which is done later.
> I know that code has been changed over the years, perhaps this is > something that was fixed upstream and the real time tree didn't realize > there was no longer a need to fix anything? > > Or am I missing something subtle when reading the idtentry assembly?
It certainly is true that the code changed over the years. The per-CPU stack is one problem, the siglock in atomic context is the other one. Thank you for the input. Let me digest the informations I have here and get back.
> Eric
Sebastian
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