From: Jack Steiner <steiner@sgi.com>
To: linux-ia64@vger.kernel.org
Subject: [PATCH] - Missing check for TIF_WORK if trace/audit enabled
Date: Wed, 15 Feb 2006 21:29:22 +0000 [thread overview]
Message-ID: <20060215212922.GA28239@sgi.com> (raw)
It appears that if trace/audit is enabled, the kernel fails to
check for pending work before returning to user mode.
Signed-off-by: Jack Steiner <steiner@sgi.com>
---
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:
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 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:
next reply other threads:[~2006-02-15 21:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-15 21:29 Jack Steiner [this message]
2006-02-16 1:03 ` [PATCH] - Missing check for TIF_WORK if trace/audit enabled Chen, Kenneth W
2006-02-16 1:46 ` Jack Steiner
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