Messages in this thread | | | Date | Mon, 27 Feb 2012 14:24:04 -0600 | Subject | Re: [PATCH v11 08/12] signal, x86: add SIGSYS info and make it synchronous. | From | Will Drewry <> |
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On Mon, Feb 27, 2012 at 11:22 AM, Oleg Nesterov <oleg@redhat.com> wrote: > On 02/24, Will Drewry wrote: >> >> To ensure that SIGSYS delivery occurs on return from the triggering >> system call, SIGSYS is added to the SYNCHRONOUS_MASK macro. > > Hmm. Can't understand... please help. > >> #define SYNCHRONOUS_MASK \ >> (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ >> - sigmask(SIGTRAP) | sigmask(SIGFPE)) >> + sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) > > Why? > > SYNCHRONOUS_MASK just tells dequeue_signal() "pick them first". > This is needed to make sure that the handler for, say SIGSEGV, > can use ucontext->ip as a faulting addr.
I think that Roland covered this. (Since the syscall_rollback was called it's nice to let our handler get first go.)
> But seccomp adds info->si_call_addr, this looks unneeded.
True enough. I can drop it. It'd only be useful if the SIGSYS wasn't being forced and the signal was being handled without ucontext_t access.
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