Messages in this thread | | | Date | Mon, 8 Apr 2024 18:22:59 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCHv2 1/3] uprobe: Add uretprobe syscall to speed up return probe |
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On 04/08, Jiri Olsa wrote: > > On Fri, Apr 05, 2024 at 01:02:30PM +0200, Oleg Nesterov wrote: > > > > And what should sys_uretprobe() do if it is not called from the trampoline? > > I'd prefer force_sig(SIGILL) to punish the abuser ;) OK, OK, EINVAL. > > so the similar behaviour with int3 ends up with immediate SIGTRAP > and not invoking pending uretprobe consumers, like: > > - setup uretprobe for foo > - foo() { > executes int 3 -> sends SIGTRAP > } > > because the int3 handler checks if it got executed from the uretprobe's > trampoline.
.. or the task has uprobe at this address
> if not it treats that int3 as regular trap
Yes this mimics the "default" behaviour without uprobes/uretprobes
> so I think we should mimic int3 behaviour and: > > - setup uretprobe for foo > - foo() { > uretprobe_syscall -> check if we got executed from uretprobe's > trampoline and send SIGILL if that's not the case
Agreed,
> I think it's better to have the offending process killed right away, > rather than having more undefined behaviour, waiting for final 'ret' > instruction that jumps to uretprobe trampoline and causes SIGILL
Agreed. In fact I think it should be also killed if copy_to/from_user() fails by the same reason.
Oleg.
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