diff mbox

sparc64: fix for user probes in high memory

Message ID 4e296aa1-f5b2-3d50-ae08-1a9f9cc70a45@oracle.com
State Accepted
Delegated to: David Miller
Headers show

Commit Message

Eric Saint Etienne Feb. 6, 2017, 2:32 p.m. UTC 
When returning from the user probe code into userspace process, PC & NPC are
truncated to 32 bits.

Due to shared libraries getting loaded very high in the virtual address 
space of
the process, placing a user probe inside a shared library makes the kernel
return into the process at the wrong address, causing it to seg'fault 
most of
the time.

This patch prevents truncating PC and NPC.

Signed-off-by: Eric Saint Etienne <eric.saint.etienne@oracle.com>
Reviewed-by: David Aldridge <david.j.aldridge@oracle.com>
---
  arch/sparc/include/asm/uprobes.h |    4 ++--
  1 files changed, 2 insertions(+), 2 deletions(-)

--
1.7.1

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Comments

David Miller Feb. 23, 2017, 4:23 p.m. UTC | #1 
From: Eric Saint Etienne <eric.saint.etienne@oracle.com>
Date: Mon, 6 Feb 2017 14:32:41 +0000

> When returning from the user probe code into userspace process, PC &
> NPC are
> truncated to 32 bits.
> 
> Due to shared libraries getting loaded very high in the virtual
> address space of
> the process, placing a user probe inside a shared library makes the
> kernel
> return into the process at the wrong address, causing it to seg'fault
> most of
> the time.
> 
> This patch prevents truncating PC and NPC.
> 
> Signed-off-by: Eric Saint Etienne <eric.saint.etienne@oracle.com>
> Reviewed-by: David Aldridge <david.j.aldridge@oracle.com>

Applied.
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diff mbox

Patch

diff --git a/arch/sparc/include/asm/uprobes.h 
b/arch/sparc/include/asm/uprobes.h
index f87aae5..36196c1 100644
--- a/arch/sparc/include/asm/uprobes.h
+++ b/arch/sparc/include/asm/uprobes.h
@@ -42,8 +42,8 @@  struct arch_uprobe {
  };

  struct arch_uprobe_task {
-       u32 saved_tpc;
-       u32 saved_tnpc;
+       u64 saved_tpc;
+       u64 saved_tnpc;
  };

  struct task_struct;