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authorPrasanna S Panchamukhi <prasanna@in.ibm.com>2005-05-05 16:15:40 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-05-05 16:36:39 -0700
commit0b9e2cac8a56e197d0a9e06268db4c8652d23dd5 (patch)
tree6bab2badad512d39c2b606e8c2c12d271c1bee35 /arch/i386/kernel
parent3a0a64e6c917b2ccc311cf978cc9d7eef7b31c47 (diff)
[PATCH] Kprobes: Incorrect handling of probes on ret/lret instruction
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>
Diffstat (limited to 'arch/i386/kernel')
-rw-r--r--arch/i386/kernel/kprobes.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index 67168165924..59ff9b45506 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -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;