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From: Jack Steiner <steiner@sgi.com>
To: linux-ia64@vger.kernel.org
Subject: Re: [PATCH] - Missing check for TIF_WORK if trace/audit enabled
Date: Thu, 16 Feb 2006 01:46:50 +0000	[thread overview]
Message-ID: <20060216014650.GA23758@sgi.com> (raw)
In-Reply-To: <20060215212922.GA28239@sgi.com>


It appears that if auditing is enabled, the kernel fails to
check for pending signals before returning to user mode. 

	Signed-off-by: Jack Steiner <steiner@sgi.com>


---

Tony - I think this should go into 2.6.16

Second version. Moved the ".ret" label as suggested by Ken.


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:
	
	ia64_trace_syscall -> work_pending_syscall_end -> work_processed_syscall

work_processed_syscall assumes p6 indicates if the kernel is returning to user mode.
Nothing set p6 for this particular path.



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 19:35:24.539592133 -0600
@@ -569,7 +569,9 @@ 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
-.ret3:	br.cond.sptk .work_pending_syscall_end
+.ret3:
+(pUStk)	cmp.eq.unc p6,p0=r0,r0			// p6 <- pUStk
+	br.cond.sptk .work_pending_syscall_end
 
 strace_error:
 	ld8 r3=[r2]				// load pt_regs.r8

      parent reply	other threads:[~2006-02-16  1:46 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
2006-02-16  1:46 ` Jack Steiner [this message]

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