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authorOleg Nesterov <oleg@redhat.com>2012-09-29 21:31:08 +0200
committerAnton Arapov <anton@redhat.com>2012-10-29 11:47:47 +0100
commit21d337e9688116ac3e416e181650127f89a75cb9 (patch)
tree8b15b76d7563e939c36da6967b2580155db25421
parentc1ee69c19b3bf0d8f4e26306cccdf4398be29cb6 (diff)
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uprobes/x86: Only rep+nop can be emulated correctly
__skip_sstep() correctly detects the "nontrivial" nop insns, but since it doesn't update regs->ip we can not really skip "0x0f 0x1f | 0x0f 0x19 | 0x87 0xc0", the probed application is killed by SIGILL'ed handle_swbp(). Remove these additional checks. If we want to implement this correctly we need to know the full insn length to update ->ip. rep* + nop is fine even without updating ->ip. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
-rw-r--r--arch/x86/kernel/uprobes.c16
1 files changed, 2 insertions, 14 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 9538f00..aafa555 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -651,31 +651,19 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
/*
* Skip these instructions as per the currently known x86 ISA.
- * 0x66* { 0x90 | 0x0f 0x1f | 0x0f 0x19 | 0x87 0xc0 }
+ * rep=0x66*; nop=0x90
*/
static bool __skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
int i;
for (i = 0; i < MAX_UINSN_BYTES; i++) {
- if ((auprobe->insn[i] == 0x66))
+ if (auprobe->insn[i] == 0x66)
continue;
if (auprobe->insn[i] == 0x90)
return true;
- if (i == (MAX_UINSN_BYTES - 1))
- break;
-
- if ((auprobe->insn[i] == 0x0f) && (auprobe->insn[i+1] == 0x1f))
- return true;
-
- if ((auprobe->insn[i] == 0x0f) && (auprobe->insn[i+1] == 0x19))
- return true;
-
- if ((auprobe->insn[i] == 0x87) && (auprobe->insn[i+1] == 0xc0))
- return true;
-
break;
}
return false;