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From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: linux-ia64@vger.kernel.org
Subject: RE: [PATCH] - Missing check for TIF_WORK if trace/audit enabled
Date: Thu, 16 Feb 2006 01:03:06 +0000	[thread overview]
Message-ID: <200602160103.k1G136g12834@unix-os.sc.intel.com> (raw)
In-Reply-To: <20060215212922.GA28239@sgi.com>

Jack Steiner wrote on Wednesday, February 15, 2006 1:29 PM
> It appears that if trace/audit is enabled, the kernel fails to
> check for pending work before returning to user mode. 
> 
> Tony / Ken - check this carefully. This is not easy code to understand :-)
> 
> I noticed the problem running a signal test that sent SIGUSR2 signals to 
> itself. Signals were being dropped. I isolated the problem to an uninitialzed
> p6:


Jack, I agree with this fix.  The only request I have is to move the .ret3
label up before cmp inst, so cmp and br end up in the same instruction bundle
instead of two right now.


> Index: linux/arch/ia64/kernel/entry.S
> =================================> --- linux.orig/arch/ia64/kernel/entry.S	2006-02-15 12:32:49.836316366 -0600
> +++ linux/arch/ia64/kernel/entry.S	2006-02-15 15:09:49.983620290 -0600
> @@ -569,6 +569,7 @@ GLOBAL_ENTRY(ia64_trace_syscall)
>  .mem.offset 0,0; st8.spill [r2]=r8		// store return value in slot for r8
>  .mem.offset 8,0; st8.spill [r3]=r10		// clear error indication in slot for r10
>  	br.call.sptk.many rp=syscall_trace_leave // give parent a chance to catch return value
> +(pUStk)	cmp.eq.unc p6,p0=r0,r0			// p6 <- pUStk
>  .ret3:	br.cond.sptk .work_pending_syscall_end
>  
>  strace_error:


  reply	other threads:[~2006-02-16  1:03 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-02-15 21:29 [PATCH] - Missing check for TIF_WORK if trace/audit enabled Jack Steiner
2006-02-16  1:03 ` Chen, Kenneth W [this message]
2006-02-16  1:46 ` Jack Steiner

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