On Tue, May 19, 2015 at 04:58:14PM +0300, Eugene Shatokhin wrote: > Commit c80e5c0c23ce2282476fdc64c4b5e3d3a40723fd upstream. > This is the backport of that fix for 3.16.y-3.18.y. >
Thank you, Eugene. I'll queue this for the 3.16 kernel. Cheers, -- Luís > On x86-64, __copy_instruction() always returns 0 (error) if the > instruction uses %rip-relative addressing. This is because > kernel_insn_init() is called the second time for 'insn' instance > in such cases and sets all its fields to 0. > > Because of this, trying to place a kprobe on such instruction > will fail, register_kprobe() will return -EINVAL. > > This patch fixes the problem. > > Signed-off-by: Eugene Shatokhin <[email protected]> > --- > arch/x86/kernel/kprobes/core.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c > index 93d2c04..f2e281c 100644 > --- a/arch/x86/kernel/kprobes/core.c > +++ b/arch/x86/kernel/kprobes/core.c > @@ -330,13 +330,16 @@ int __copy_instruction(u8 *dest, u8 *src) > { > struct insn insn; > kprobe_opcode_t buf[MAX_INSN_SIZE]; > + int length; > > kernel_insn_init(&insn, (void *)recover_probed_instruction(buf, > (unsigned long)src)); > insn_get_length(&insn); > + length = insn.length; > + > /* Another subsystem puts a breakpoint, failed to recover */ > if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION) > return 0; > - memcpy(dest, insn.kaddr, insn.length); > + memcpy(dest, insn.kaddr, length); > > #ifdef CONFIG_X86_64 > if (insn_rip_relative(&insn)) { > @@ -366,7 +369,7 @@ int __copy_instruction(u8 *dest, u8 *src) > *(s32 *) disp = (s32) newdisp; > } > #endif > - return insn.length; > + return length; > } > > static int arch_copy_kprobe(struct kprobe *p) > -- > 2.3.2 > > -- > To unsubscribe from this list: send the line "unsubscribe stable" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
