This is a note to let you know that I've just added the patch titled
ARC: Ignore ptrace SETREGSET request for synthetic register "stop_pc"
to the 3.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arc-ignore-ptrace-setregset-request-for-synthetic-register-stop_pc.patch
and it can be found in the queue-3.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5b24282846c064ee90d40fcb3a8f63b8e754fd28 Mon Sep 17 00:00:00 2001
From: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Date: Thu, 10 Oct 2013 19:33:57 +0530
Subject: ARC: Ignore ptrace SETREGSET request for synthetic register "stop_pc"
From: Vineet Gupta <vgupta@xxxxxxxxxxxx>
commit 5b24282846c064ee90d40fcb3a8f63b8e754fd28 upstream.
ARCompact TRAP_S insn used for breakpoints, commits before exception is
taken (updating architectural PC). So ptregs->ret contains next-PC and
not the breakpoint PC itself. This is different from other restartable
exceptions such as TLB Miss where ptregs->ret has exact faulting PC.
gdb needs to know exact-PC hence ARC ptrace GETREGSET provides for
@stop_pc which returns ptregs->ret vs. EFA depending on the
situation.
However, writing stop_pc (SETREGSET request), which updates ptregs->ret
doesn't makes sense stop_pc doesn't always correspond to that reg as
described above.
This was not an issue so far since user_regs->ret / user_regs->stop_pc
had same value and both writing to ptregs->ret was OK, needless, but NOT
broken, hence not observed.
With gdb "jump", they diverge, and user_regs->ret updating ptregs is
overwritten immediately with stop_pc, which this patch fixes.
Reported-by: Anton Kolesov <akolesov@xxxxxxxxxxxx>
Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arc/kernel/ptrace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arc/kernel/ptrace.c
+++ b/arch/arc/kernel/ptrace.c
@@ -102,7 +102,7 @@ static int genregs_set(struct task_struc
REG_IGNORE_ONE(pad2);
REG_IN_CHUNK(callee, efa, cregs); /* callee_regs[r25..r13] */
REG_IGNORE_ONE(efa); /* efa update invalid */
- REG_IN_ONE(stop_pc, &ptregs->ret); /* stop_pc: PC update */
+ REG_IGNORE_ONE(stop_pc); /* PC updated via @ret */
return ret;
}
Patches currently in stable-queue which might be from vgupta@xxxxxxxxxxxx are
queue-3.11/arc-fix-32-bit-wrap-around-in-access_ok.patch
queue-3.11/arc-fix-signal-frame-management-for-sa_siginfo.patch
queue-3.11/arc-ignore-ptrace-setregset-request-for-synthetic-register-stop_pc.patch
queue-3.11/arc-handle-zero-overhead-loop-in-unaligned-access-handler.patch
queue-3.11/arc-fix-__udelay-calculation.patch
queue-3.11/arc-workaround-spinlock-livelock-in-smp-systemc-simulation.patch
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