Hey Oleg,
> A separate "patch", just to emphasize that I do not know what
> actually abort_xol() should do! I do not understand this asm
> magic.
>
> This patch simply changes regs->ip back to the probed insn,
> obviously this is not enough to handle UPROBES_FIX_*. Please
> take care.
>
> If it is not clear, abort_xol() is needed when we should
> re-execute the original insn (replaced with int3), see the
> next patch.
We should be removing the breakpoint in abort_xol().
Otherwise if we just set the instruction pointer to int3 and signal a
sigill, then the user may be confused why a breakpoint is generating
SIGILL.
> ---
> arch/x86/include/asm/uprobes.h | 1 +
> arch/x86/kernel/uprobes.c | 9 +++++++++
> 2 files changed, 10 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h
> index f0fbdab..6209da1 100644
> --- a/arch/x86/include/asm/uprobes.h
> +++ b/arch/x86/include/asm/uprobes.h
> @@ -51,6 +51,7 @@ extern void set_instruction_pointer(struct pt_regs *regs, unsigned long vaddr);
> extern int pre_xol(struct uprobe *uprobe, struct pt_regs *regs);
> extern int post_xol(struct uprobe *uprobe, struct pt_regs *regs);
> extern bool xol_was_trapped(struct task_struct *tsk);
> +extern void abort_xol(struct pt_regs *regs);
> extern int uprobe_exception_notify(struct notifier_block *self,
> unsigned long val, void *data);
> #endif /* _ASM_UPROBES_H */
> diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
> index c861c27..bc11a89 100644
> --- a/arch/x86/kernel/uprobes.c
> +++ b/arch/x86/kernel/uprobes.c
> @@ -511,6 +511,15 @@ bool xol_was_trapped(struct task_struct *tsk)
> return false;
> }
>
> +void abort_xol(struct pt_regs *regs)
> +{
> + // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> + // !!! Dear Srikar and Ananth, please implement me !!!
> + // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> + struct uprobe_task *utask = current->utask;
> + regs->ip = utask->vaddr;
nit:
Shouldnt we be setting the ip to the next instruction after this
instruction?
> +}
> +
> /*
> * Called after single-stepping. To avoid the SMP problems that can
> * occur when we temporarily put back the original opcode to
I have applied all your patches and ran tests, the tests are all
passing.
I will fold them into my patches and send them out.
--
Thanks and Regards
Srikar
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