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Subject[PATCH 3/4] x86: ptrace: do not sign-extend orig_ax on write
Date
The high 32 bits of orig_ax will be ignored when it matters,
so don't fiddle them when setting it.

Signed-off-by: Roland McGrath <roland@redhat.com>
---
arch/x86/kernel/ptrace.c | 19 +------------------
1 files changed, 1 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 8d7d5c9..52222fa 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -325,16 +325,6 @@ static int putreg(struct task_struct *child,
return set_flags(child, value);

#ifdef CONFIG_X86_64
- /*
- * Orig_ax is really just a flag with small positive and
- * negative values, so make sure to always sign-extend it
- * from 32 bits so that it works correctly regardless of
- * whether we come from a 32-bit environment or not.
- */
- case offsetof(struct user_regs_struct, orig_ax):
- value = (long) (s32) value;
- break;
-
case offsetof(struct user_regs_struct,fs_base):
if (value >= TASK_SIZE_OF(child))
return -EIO;
@@ -1121,17 +1111,10 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 value)
R32(esi, si);
R32(ebp, bp);
R32(eax, ax);
+ R32(orig_eax, orig_ax);
R32(eip, ip);
R32(esp, sp);

- case offsetof(struct user32, regs.orig_eax):
- /*
- * Sign-extend the value so that orig_eax = -1
- * causes (long)orig_ax < 0 tests to fire correctly.
- */
- regs->orig_ax = (long) (s32) value;
- break;
-
case offsetof(struct user32, regs.eflags):
return set_flags(child, value);


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