First of all, thanks a lot for your report. 2012/10/24 Sergey Senozhatsky <[email protected]>: > On (10/24/12 20:06), Oleg Nesterov wrote: >> On 10/24, Sergey Senozhatsky wrote: >> > >> > small question, >> > >> > ptrace_notify() and forward calls are able to both indirectly and directly >> > call schedule(), >> > /* direct call from ptrace_stop()*/, >> > should, in this case, rcu_user_enter() be called before >> > tracehook_report_syscall_exit(regs, step) >> > and ptrace chain? >> >> Well, I don't really understand this magic... but why? >> > > My understanding is (I may be wrong) that we can schedule() from ptrace chain > to > some arbitrary task, which will continue its execution from the point where > RCU assumes > CPU as not idle, while CPU in fact still in idle state -- no one said > rcu_idle_exit() > (or similar) prior to schedule() call.
Yeah but when we are in syscall_trace_leave(), the CPU shouldn't be in RCU idle mode. That's where the bug is. How do you manage to trigger this bug? > > if so, does the same apply to in_user? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
