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[PATCH] Kprobes: Incorrect handling of probes on ret/lret instruction

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Kprobes could not handle the insertion of a probe on the ret/lret
instruction and used to oops after single stepping since kprobes was
modifying eip/rip incorrectly.  Adjustment of eip/rip is not required after
single stepping in case of ret/lret instruction, because eip/rip points to
the correct location after execution of the ret/lret instruction.  This
patch fixes the above problem.

Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Prasanna S Panchamukhi 2005-05-05 16:15:40 -07:00 committed by Linus Torvalds
parent 3a0a64e6c9
commit 0b9e2cac8a
2 changed files with 14 additions and 0 deletions
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7
arch/i386/kernel/kprobes.c
View file

@ -217,6 +217,13 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs)
*tos &= ~(TF_MASK | IF_MASK);
*tos |= kprobe_old_eflags;
break;
case 0xc3: /* ret/lret */
case 0xcb:
case 0xc2:
case 0xca:
regs->eflags &= ~TF_MASK;
/* eip is already adjusted, no more changes required*/
return;
case 0xe8: /* call relative - Fix return addr */
*tos = orig_eip + (*tos - copy_eip);
break;

7
arch/x86_64/kernel/kprobes.c
View file

@ -355,6 +355,13 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs)
*tos &= ~(TF_MASK | IF_MASK);
*tos |= kprobe_old_rflags;
break;
case 0xc3: /* ret/lret */
case 0xcb:
case 0xc2:
case 0xca:
regs->eflags &= ~TF_MASK;
/* rip is already adjusted, no more changes required*/
return;
case 0xe8: /* call relative - Fix return addr */
*tos = orig_rip + (*tos - copy_rip);
break;