Messages in this thread |  | | Date | Sun, 4 Dec 2022 14:30:01 -0800 | From | Alexei Starovoitov <> | Subject | Re: [PATCH v2] panic: Taint kernel if fault injection has been used |
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On Mon, Dec 05, 2022 at 07:22:44AM +0900, Masami Hiramatsu (Google) wrote: > From: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > Since the function error injection framework in the fault injection > subsystem can change the function code flow forcibly, it may cause > unexpected behavior (and that is the purpose of this feature) even > if it is applied to the ALLOW_ERROR_INJECTION functions. > So this feature must be used only for debugging or testing purpose.
The whole idea of tainting for kernel debugging is questionable. There are many other *inject* kconfigs and other debug flags for link lists, RCU, sleeping, etc. None of them taint the kernel.
> To identify this in the kernel oops message, add a new taint flag
Have you ever seen a single oops message because of this particular error injection?
> for the fault injection. This taint flag will be set by either > function error injection is used or the BPF use the kprobe_override > on error injectable functions (identified by ALLOW_ERROR_INJECTION).
...
> /* set the new array to event->tp_event and set event->prog */ > + if (prog->kprobe_override) > + add_taint(TAINT_FAULT_INJECTED, LOCKDEP_NOW_UNRELIABLE);
Nack for bpf bits.
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