Re: [v8-users] Setting an execution limit
There is always a stack limit, which always prevents infinite recursion; as well as, in fact, finite but very deep recursion. As Ben said, the only way to prevent infinite or long-running loops is by interrupting the program from another thread. You may have heard of the *Halting Problem*, TL;DR: there really can be no other way, because in the general case it is *impossible* to predict whether a loop will terminate at all, and how soon. There is no way to set a limit for executed instructions. You could hack it, but it's going to be non-trivial. On Sun, Nov 20, 2016 at 11:11 PM, wrote: > I don't think there's any way. V8 JavaScript code is compiled to native > code, and no instrumentation is really possible on that. > > On Sunday, November 20, 2016 at 10:18:24 AM UTC-8, James Lovejoy wrote: >> >> Really I need something a little more deterministic than a time limit. Is >> there a way to set an instruction limit? Or perhaps something similar to >> lua_sethook (http://pgl.yoyo.org/luai/i/lua_sethook) in Lua which calls >> a callback every given number of instructions. >> >> On Sun, Nov 20, 2016 at 4:02 AM, Ben Noordhuis >> wrote: >> >>> On Sat, Nov 19, 2016 at 10:11 PM, James Lovejoy >>> wrote: >>> > Hi, >>> > >>> > Is there a way to set a hard execution limit in the V8 engine? I want >>> to be >>> > able to prevent things like infinite loops and recursions. I realise >>> that >>> > since V8 compiles to machine code I don't get a program counter or >>> anything. >>> > I feel like setting the "stack limit" is the right way to go but the >>> usage >>> > of this feature from the documentation is unclear. Can someone guide >>> me as >>> > to how to achieve such a limit? >>> > >>> > James >>> >>> If 'execution limit' means 'time limit': start a watchdog thread and >>> call v8::Isolate::TerminateExecution() from that thread on timeout. >>> It must be a thread, it's not safe to call from a signal handler. >>> >>> -- >>> -- >>> v8-users mailing list >>> v8-u...@googlegroups.com >>> http://groups.google.com/group/v8-users >>> --- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "v8-users" group. >>> To unsubscribe from this topic, visit https://groups.google.com/d/to >>> pic/v8-users/Qwdd66xCtTU/unsubscribe. >>> To unsubscribe from this group and all its topics, send an email to >>> v8-users+u...@googlegroups.com. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- > -- > v8-users mailing list > v8-users@googlegroups.com > http://groups.google.com/group/v8-users > --- > You received this message because you are subscribed to the Google Groups > "v8-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to v8-users+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [v8-users] Setting an execution limit
I don't think there's any way. V8 JavaScript code is compiled to native code, and no instrumentation is really possible on that. On Sunday, November 20, 2016 at 10:18:24 AM UTC-8, James Lovejoy wrote: > > Really I need something a little more deterministic than a time limit. Is > there a way to set an instruction limit? Or perhaps something similar to > lua_sethook (http://pgl.yoyo.org/luai/i/lua_sethook) in Lua which calls a > callback every given number of instructions. > > On Sun, Nov 20, 2016 at 4:02 AM, Ben Noordhuis > wrote: > >> On Sat, Nov 19, 2016 at 10:11 PM, James Lovejoy > > wrote: >> > Hi, >> > >> > Is there a way to set a hard execution limit in the V8 engine? I want >> to be >> > able to prevent things like infinite loops and recursions. I realise >> that >> > since V8 compiles to machine code I don't get a program counter or >> anything. >> > I feel like setting the "stack limit" is the right way to go but the >> usage >> > of this feature from the documentation is unclear. Can someone guide me >> as >> > to how to achieve such a limit? >> > >> > James >> >> If 'execution limit' means 'time limit': start a watchdog thread and >> call v8::Isolate::TerminateExecution() from that thread on timeout. >> It must be a thread, it's not safe to call from a signal handler. >> >> -- >> -- >> v8-users mailing list >> v8-u...@googlegroups.com >> http://groups.google.com/group/v8-users >> --- >> You received this message because you are subscribed to a topic in the >> Google Groups "v8-users" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/v8-users/Qwdd66xCtTU/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> v8-users+u...@googlegroups.com . >> For more options, visit https://groups.google.com/d/optout. >> > > -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [v8-users] Setting an execution limit
Really I need something a little more deterministic than a time limit. Is there a way to set an instruction limit? Or perhaps something similar to lua_sethook (http://pgl.yoyo.org/luai/i/lua_sethook) in Lua which calls a callback every given number of instructions. On Sun, Nov 20, 2016 at 4:02 AM, Ben Noordhuis wrote: > On Sat, Nov 19, 2016 at 10:11 PM, James Lovejoy > wrote: > > Hi, > > > > Is there a way to set a hard execution limit in the V8 engine? I want to > be > > able to prevent things like infinite loops and recursions. I realise that > > since V8 compiles to machine code I don't get a program counter or > anything. > > I feel like setting the "stack limit" is the right way to go but the > usage > > of this feature from the documentation is unclear. Can someone guide me > as > > to how to achieve such a limit? > > > > James > > If 'execution limit' means 'time limit': start a watchdog thread and > call v8::Isolate::TerminateExecution() from that thread on timeout. > It must be a thread, it's not safe to call from a signal handler. > > -- > -- > v8-users mailing list > v8-users@googlegroups.com > http://groups.google.com/group/v8-users > --- > You received this message because you are subscribed to a topic in the > Google Groups "v8-users" group. > To unsubscribe from this topic, visit https://groups.google.com/d/ > topic/v8-users/Qwdd66xCtTU/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > v8-users+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [v8-users] Setting an execution limit
On Sat, Nov 19, 2016 at 10:11 PM, James Lovejoy wrote: > Hi, > > Is there a way to set a hard execution limit in the V8 engine? I want to be > able to prevent things like infinite loops and recursions. I realise that > since V8 compiles to machine code I don't get a program counter or anything. > I feel like setting the "stack limit" is the right way to go but the usage > of this feature from the documentation is unclear. Can someone guide me as > to how to achieve such a limit? > > James If 'execution limit' means 'time limit': start a watchdog thread and call v8::Isolate::TerminateExecution() from that thread on timeout. It must be a thread, it's not safe to call from a signal handler. -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[v8-users] Setting an execution limit
Hi, Is there a way to set a hard execution limit in the V8 engine? I want to be able to prevent things like infinite loops and recursions. I realise that since V8 compiles to machine code I don't get a program counter or anything. I feel like setting the "stack limit" is the right way to go but the usage of this feature from the documentation is unclear. Can someone guide me as to how to achieve such a limit? James -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
