Re: [parisc] double restarts on multiple signal arrivals

[John David Anglin <dave.anglin@xxxxxxxx>]

On 20-May-12, at 5:04 AM, Al Viro wrote:

> Actually, looks like I am missing something, but it's not  
> particulary subtle.
> SYSCALL_TRACE is needed for do_syscall_trace_enter() to do anything;
> any of SYSCALL_TRACE/SINGLESTEP/BLOCKSTEP is makes  
> do_syscall_trace_leave()
> do things.  So checking one bit in flags is not enough - any of  
> those 3 is
> a reason for taking the slow path.  The point still stands, though -
> 	mfctl   %cr30, %r1
> 	LDREG   TI_FLAGS(%r1),%r1
> 	ldi	(_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | _TIF_BLOCKSTEP), %r19
>        and,COND(=) %r19, %r1, %r0
> 	b,n	.Ltracesys
> would still be no worse on the fast path and would not hit the slow  
> path in
> a lot of cases when the current code does it for no apparent reason.
>
> Comments?

This looks good to me.  There is similar code in entry.S.

I added the above change to my patch set for stable 3.3.6.  System still
boots.  I singled stepped /bin/ls through a directory listing and it  
seemed
to work.

Dave
--
John David Anglin	dave.anglin@xxxxxxxx



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