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SubjectRe: [PATCH 3/7] uprobes/x86: Conditionalize the usage of handle_riprel_insn()
(2014/04/01 4:44), Oleg Nesterov wrote:
> arch_uprobe_analyze_insn() calls handle_riprel_insn() at the start,
> but only "0xff" and "default" cases need the UPROBE_FIX_RIP_ logic.
> Move the callsite into "default" case and change the "0xff" case to
> fall-through.
>
> We are going to add the various hooks to handle the rip-relative
> jmp/call instructions (and more), we need this change to enforce the
> fact that the new code can't conflict with is_riprel_insn() code.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Hmm, this seems not obviously reasonable at this point.
However, the code itself is not wrong. Could you merge
this change to that new hooks?

Thank you,

> ---
> arch/x86/kernel/uprobes.c | 6 ++----
> 1 files changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
> index 098e56e..d72dfbf 100644
> --- a/arch/x86/kernel/uprobes.c
> +++ b/arch/x86/kernel/uprobes.c
> @@ -376,8 +376,6 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
> * and annotate arch_uprobe->fixups accordingly. To start with, ->fixups
> * is either zero or it reflects rip-related fixups.
> */
> - handle_riprel_insn(auprobe, mm, &insn);
> -
> switch (OPCODE1(&insn)) {
> case 0x9d: /* popf */
> auprobe->fixups |= UPROBE_FIX_SETF;
> @@ -406,9 +404,9 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
> case 4: case 5: /* jmp or ljmp, indirect */
> fix_ip = false;
> }
> - break;
> + /* fall through */
> default:
> - break;
> + handle_riprel_insn(auprobe, mm, &insn);
> }
>
> if (fix_ip)
>


--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com




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