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| author | Oleg Nesterov <oleg@redhat.com> | 2012-09-29 21:31:08 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2012-10-07 21:19:40 +0200 |
| commit | b64b9c937a533f0bfbfc9f6ac93d3c3e2f97ab02 (patch) | |
| tree | a0d09be7f8be3c3afda0a2be45378a2935cba9f3 /arch/x86 | |
| parent | ec75fba93ef0c00c91545b5e53841a80cffad0c4 (diff) | |
| download | op-kernel-dev-b64b9c937a533f0bfbfc9f6ac93d3c3e2f97ab02.zip op-kernel-dev-b64b9c937a533f0bfbfc9f6ac93d3c3e2f97ab02.tar.gz | |
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>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 16 |
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; |
