Re: [PATCH] i386 & x86_64: Live Patching Funcion on 2.6.11.7
Daniel Jacobowitz wrote: >On Mon, Apr 18, 2005 at 10:41:23AM +0900, Takashi Ikebe wrote: > > >>Daniel-san, >>GDB based approach seems not fit to our requirements. GDB(ptrace) based >>functions are basically need to be done when target process is stopping. >>From our experience, sometimes patches became to dozens to hundreds at >>one patching, and in this case GDB based approach cause target process's >>availability descent. >> >> > >That's right, it does require the target process be stopped. If it >isn't stopped how do you know it isn't executing the same instruction >you're currently patching? > >Even with hundreds of kilobytes of patch, I have trouble imagining this >takes a substantial amount of time. > > Pannus patch does not require target process stop while loading(mapping) patch module to target process memory, but as you described, target process stopping is needed whenever check EIP not to conflict, and overwrite jump assembly code.(This makes only few milliseconds target process stopping. Even on hundreds, it only takes dozens mill-seconds yet.) Typically telecoms application needs soft real time, and has timeout. This kind of framework can not stop target process so long(Should be dozens milliseconds at worst). We want not to stop target process whenever patch module is loading we want not to stop target process as possible as. -- Takashi Ikebe NTT Network Service Systems Laboratories 9-11, Midori-Cho 3-Chome Musashino-Shi, Tokyo 180-8585 Japan Tel : +81 422 59 4246, Fax : +81 422 60 4012 e-mail : [EMAIL PROTECTED] - 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/
Re: [PATCH] i386 & x86_64: Live Patching Funcion on 2.6.11.7
On Mon, Apr 18, 2005 at 10:41:23AM +0900, Takashi Ikebe wrote: > Daniel-san, > GDB based approach seems not fit to our requirements. GDB(ptrace) based > functions are basically need to be done when target process is stopping. > From our experience, sometimes patches became to dozens to hundreds at > one patching, and in this case GDB based approach cause target process's > availability descent. That's right, it does require the target process be stopped. If it isn't stopped how do you know it isn't executing the same instruction you're currently patching? Even with hundreds of kilobytes of patch, I have trouble imagining this takes a substantial amount of time. -- Daniel Jacobowitz CodeSourcery, LLC - 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/
Re: [PATCH] i386 & x86_64: Live Patching Funcion on 2.6.11.7
Daniel-san, David-san, Pannus project has two targets. One is user-mode application live patching, and the other one is kernel live patching. What we posted now is user-mode application live patching function. >If I'm right, I'm not sure why some of the bits of it were done >separately instead of via the existing ptrace mechanism. And GDB >would appreciate a mechanism for mmap/munmap/mprotect in a debugged >process, also. Daniel-san, GDB based approach seems not fit to our requirements. GDB(ptrace) based functions are basically need to be done when target process is stopping. From our experience, sometimes patches became to dozens to hundreds at one patching, and in this case GDB based approach cause target process's availability descent. Patch exceeds 50k, so I cut comments and separate architecture, and post as in line. David S. Miller wrote: On Sun, 17 Apr 2005 14:51:43 -0400 Daniel Jacobowitz <[EMAIL PROTECTED]> wrote: Takashi-san's description was not very clear, but it sounds like it's a patching mechanism for userspace applications - not for kernel space. So kprobes would not be a good fit. I saw the presentation of this stuff at the Linux Kernel conference last year in Tokyo. I'm pretty sure it's for the kernel. :-) - 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/ -- Takashi Ikebe NTT Network Service Systems Laboratories 9-11, Midori-Cho 3-Chome Musashino-Shi, Tokyo 180-8585 Japan Tel : +81 422 59 4246, Fax : +81 422 60 4012 e-mail : [EMAIL PROTECTED] - 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/
Re: [PATCH] i386 & x86_64: Live Patching Funcion on 2.6.11.7
On Sun, 17 Apr 2005 14:51:43 -0400 Daniel Jacobowitz <[EMAIL PROTECTED]> wrote: > Takashi-san's description was not very clear, but it sounds like it's a > patching mechanism for userspace applications - not for kernel space. > So kprobes would not be a good fit. I saw the presentation of this stuff at the Linux Kernel conference last year in Tokyo. I'm pretty sure it's for the kernel. :-) - 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/
Re: [PATCH] i386 & x86_64: Live Patching Funcion on 2.6.11.7
On Sat, Apr 16, 2005 at 11:44:39PM -0700, David S. Miller wrote: > > Takashi-san, have you ever investigated using kprobes to > implement this feature? It seems a perfect fit, and would > allow support on several architectures other than just x86 > and x86_64. > > If kprobes does not meet your needs completely, it could > be trivially extended to do so. > > I think implementing something like this from scratch is > not a good idea when we have much of the needed logic and > infrastructure already. Takashi-san's description was not very clear, but it sounds like it's a patching mechanism for userspace applications - not for kernel space. So kprobes would not be a good fit. If I'm right, I'm not sure why some of the bits of it were done separately instead of via the existing ptrace mechanism. And GDB would appreciate a mechanism for mmap/munmap/mprotect in a debugged process, also. -- Daniel Jacobowitz CodeSourcery, LLC - 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/
Re: [PATCH] i386 & x86_64: Live Patching Funcion on 2.6.11.7
Takashi-san, have you ever investigated using kprobes to implement this feature? It seems a perfect fit, and would allow support on several architectures other than just x86 and x86_64. If kprobes does not meet your needs completely, it could be trivially extended to do so. I think implementing something like this from scratch is not a good idea when we have much of the needed logic and infrastructure already. - 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/
Re: [PATCH] i386 x86_64: Live Patching Funcion on 2.6.11.7
Takashi-san, have you ever investigated using kprobes to implement this feature? It seems a perfect fit, and would allow support on several architectures other than just x86 and x86_64. If kprobes does not meet your needs completely, it could be trivially extended to do so. I think implementing something like this from scratch is not a good idea when we have much of the needed logic and infrastructure already. - 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/
Re: [PATCH] i386 x86_64: Live Patching Funcion on 2.6.11.7
On Sat, Apr 16, 2005 at 11:44:39PM -0700, David S. Miller wrote: Takashi-san, have you ever investigated using kprobes to implement this feature? It seems a perfect fit, and would allow support on several architectures other than just x86 and x86_64. If kprobes does not meet your needs completely, it could be trivially extended to do so. I think implementing something like this from scratch is not a good idea when we have much of the needed logic and infrastructure already. Takashi-san's description was not very clear, but it sounds like it's a patching mechanism for userspace applications - not for kernel space. So kprobes would not be a good fit. If I'm right, I'm not sure why some of the bits of it were done separately instead of via the existing ptrace mechanism. And GDB would appreciate a mechanism for mmap/munmap/mprotect in a debugged process, also. -- Daniel Jacobowitz CodeSourcery, LLC - 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/
Re: [PATCH] i386 x86_64: Live Patching Funcion on 2.6.11.7
On Sun, 17 Apr 2005 14:51:43 -0400 Daniel Jacobowitz [EMAIL PROTECTED] wrote: Takashi-san's description was not very clear, but it sounds like it's a patching mechanism for userspace applications - not for kernel space. So kprobes would not be a good fit. I saw the presentation of this stuff at the Linux Kernel conference last year in Tokyo. I'm pretty sure it's for the kernel. :-) - 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/
Re: [PATCH] i386 x86_64: Live Patching Funcion on 2.6.11.7
Daniel-san, David-san, Pannus project has two targets. One is user-mode application live patching, and the other one is kernel live patching. What we posted now is user-mode application live patching function. If I'm right, I'm not sure why some of the bits of it were done separately instead of via the existing ptrace mechanism. And GDB would appreciate a mechanism for mmap/munmap/mprotect in a debugged process, also. Daniel-san, GDB based approach seems not fit to our requirements. GDB(ptrace) based functions are basically need to be done when target process is stopping. From our experience, sometimes patches became to dozens to hundreds at one patching, and in this case GDB based approach cause target process's availability descent. Patch exceeds 50k, so I cut comments and separate architecture, and post as in line. David S. Miller wrote: On Sun, 17 Apr 2005 14:51:43 -0400 Daniel Jacobowitz [EMAIL PROTECTED] wrote: Takashi-san's description was not very clear, but it sounds like it's a patching mechanism for userspace applications - not for kernel space. So kprobes would not be a good fit. I saw the presentation of this stuff at the Linux Kernel conference last year in Tokyo. I'm pretty sure it's for the kernel. :-) - 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/ -- Takashi Ikebe NTT Network Service Systems Laboratories 9-11, Midori-Cho 3-Chome Musashino-Shi, Tokyo 180-8585 Japan Tel : +81 422 59 4246, Fax : +81 422 60 4012 e-mail : [EMAIL PROTECTED] - 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/
Re: [PATCH] i386 x86_64: Live Patching Funcion on 2.6.11.7
On Mon, Apr 18, 2005 at 10:41:23AM +0900, Takashi Ikebe wrote: Daniel-san, GDB based approach seems not fit to our requirements. GDB(ptrace) based functions are basically need to be done when target process is stopping. From our experience, sometimes patches became to dozens to hundreds at one patching, and in this case GDB based approach cause target process's availability descent. That's right, it does require the target process be stopped. If it isn't stopped how do you know it isn't executing the same instruction you're currently patching? Even with hundreds of kilobytes of patch, I have trouble imagining this takes a substantial amount of time. -- Daniel Jacobowitz CodeSourcery, LLC - 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/
Re: [PATCH] i386 x86_64: Live Patching Funcion on 2.6.11.7
Daniel Jacobowitz wrote: On Mon, Apr 18, 2005 at 10:41:23AM +0900, Takashi Ikebe wrote: Daniel-san, GDB based approach seems not fit to our requirements. GDB(ptrace) based functions are basically need to be done when target process is stopping. From our experience, sometimes patches became to dozens to hundreds at one patching, and in this case GDB based approach cause target process's availability descent. That's right, it does require the target process be stopped. If it isn't stopped how do you know it isn't executing the same instruction you're currently patching? Even with hundreds of kilobytes of patch, I have trouble imagining this takes a substantial amount of time. Pannus patch does not require target process stop while loading(mapping) patch module to target process memory, but as you described, target process stopping is needed whenever check EIP not to conflict, and overwrite jump assembly code.(This makes only few milliseconds target process stopping. Even on hundreds, it only takes dozens mill-seconds yet.) Typically telecoms application needs soft real time, and has timeout. This kind of framework can not stop target process so long(Should be dozens milliseconds at worst). We want not to stop target process whenever patch module is loading we want not to stop target process as possible as. -- Takashi Ikebe NTT Network Service Systems Laboratories 9-11, Midori-Cho 3-Chome Musashino-Shi, Tokyo 180-8585 Japan Tel : +81 422 59 4246, Fax : +81 422 60 4012 e-mail : [EMAIL PROTECTED] - 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/
