| Message ID | 20220117145608.6781-12-madvenka@linux.microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: Reorganize the unwinder and implement stack trace reliability checks | expand |
Hi Madhavan, > Select HAVE_RELIABLE_STACKTRACE in arm64/Kconfig to allow > arch_stack_walk_reliable() to be used. > > Note that this is conditional upon STACK_VALIDATION which will be added when frame pointer validation is implemented (say > via objtool). I know that Julien Thierry published objtool support for arm64 [1], but I'm not sure if it has been updated. Could you tell me other threads if you know? [1] https://lore.kernel.org/linux-arm-kernel/20210303170932.1838634-1-jthierry@redhat.com/ Thanks, Keiya > > Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> > --- > arch/arm64/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index f6e333b59314..bc7b3514b563 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -223,6 +223,7 @@ config ARM64 > select THREAD_INFO_IN_TASK > select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD > select TRACE_IRQFLAGS_SUPPORT > + select HAVE_RELIABLE_STACKTRACE if FRAME_POINTER && STACK_VALIDATION > help > ARM 64-bit (AArch64) Linux support. > > -- > 2.25.1
I have not seen any activity on that in a long time. IIRC, Julien quit RedHat. I don't know if anyone else has taken over this work in RedHat. Sorry, I don't have any more information. Madhavan On 1/24/22 23:21, nobuta.keiya@fujitsu.com wrote: > Hi Madhavan, > >> Select HAVE_RELIABLE_STACKTRACE in arm64/Kconfig to allow >> arch_stack_walk_reliable() to be used. >> >> Note that this is conditional upon STACK_VALIDATION which will be added when frame pointer validation is implemented (say >> via objtool). > > I know that Julien Thierry published objtool support for arm64 [1], but I'm not > sure if it has been updated. Could you tell me other threads if you know? > > [1] https://lore.kernel.org/linux-arm-kernel/20210303170932.1838634-1-jthierry@redhat.com/ > > > Thanks, > Keiya > >> >> Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> >> --- >> arch/arm64/Kconfig | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index f6e333b59314..bc7b3514b563 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -223,6 +223,7 @@ config ARM64 >> select THREAD_INFO_IN_TASK >> select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD >> select TRACE_IRQFLAGS_SUPPORT >> + select HAVE_RELIABLE_STACKTRACE if FRAME_POINTER && STACK_VALIDATION >> help >> ARM 64-bit (AArch64) Linux support. >> >> -- >> 2.25.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> I have not seen any activity on that in a long time. IIRC, Julien quit RedHat. > I don't know if anyone else has taken over this work in RedHat. > > Sorry, I don't have any more information. > > Madhavan Thanks for your information. By the way, I'm considering test code for arch_stack_walk_reliable(). Specifically, I apply Suraj's patch to enable livepatch, and added a function that sleeps between SYM_CODE_START and SYM_CODE_END, then livepatch checks if the task has an unreliable stack. For now my internal test code working correctly, but my Kconfig excludes STACK_VALIDATION dependency. It seems that objtool will not be enabled yet, so I would like to test it easier. If you are already testing with this patch, could you tell me how to do it? Thanks, Keiya > > On 1/24/22 23:21, nobuta.keiya@fujitsu.com wrote: > > Hi Madhavan, > > > >> Select HAVE_RELIABLE_STACKTRACE in arm64/Kconfig to allow > >> arch_stack_walk_reliable() to be used. > >> > >> Note that this is conditional upon STACK_VALIDATION which will be > >> added when frame pointer validation is implemented (say via objtool). > > > > I know that Julien Thierry published objtool support for arm64 [1], > > but I'm not sure if it has been updated. Could you tell me other threads if you know? > > > > [1] > > https://lore.kernel.org/linux-arm-kernel/20210303170932.1838634-1-jthi > > erry@redhat.com/ > > > > > > Thanks, > > Keiya > > > >> > >> Signed-off-by: Madhavan T. Venkataraman > >> <madvenka@linux.microsoft.com> > >> --- > >> arch/arm64/Kconfig | 1 + > >> 1 file changed, 1 insertion(+) > >> > >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index > >> f6e333b59314..bc7b3514b563 100644 > >> --- a/arch/arm64/Kconfig > >> +++ b/arch/arm64/Kconfig > >> @@ -223,6 +223,7 @@ config ARM64 > >> select THREAD_INFO_IN_TASK > >> select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD > >> select TRACE_IRQFLAGS_SUPPORT > >> + select HAVE_RELIABLE_STACKTRACE if FRAME_POINTER && > >> +STACK_VALIDATION > >> help > >> ARM 64-bit (AArch64) Linux support. > >> > >> -- > >> 2.25.1 > > > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On 1/26/22 04:20, nobuta.keiya@fujitsu.com wrote: >> I have not seen any activity on that in a long time. IIRC, Julien quit RedHat. >> I don't know if anyone else has taken over this work in RedHat. >> >> Sorry, I don't have any more information. >> >> Madhavan > > Thanks for your information. > > By the way, I'm considering test code for arch_stack_walk_reliable(). > Specifically, I apply Suraj's patch to enable livepatch, and added a function > that sleeps between SYM_CODE_START and SYM_CODE_END, then livepatch > checks if the task has an unreliable stack. > For now my internal test code working correctly, but my Kconfig excludes > STACK_VALIDATION dependency. > > It seems that objtool will not be enabled yet, so I would like to test it easier. > If you are already testing with this patch, could you tell me how to do it? > > For now, I have an instrumented kernel that directly invokes arch_stack_walk_reliable() from various places in the kernel (interrupt handlers, exception handlers, ftrace entry, kprobe handler, etc). I also have a test driver to induce conditions like null pointer dereference. I use this to test different cases where arch_stack_walk_reliable() should return an error. As for livepatch testing, I have enhanced objtool and the kernel so the frame pointer can be validated dynamically rather than statically. I have tested various different livepatch selftests successfully. I have also written my own livepatch tests to add to the selftests. I am currently working on preparing an RFC patch series for review. Basically, this series implements STACK_VALIDATION in a different way. I plan to publish my work soon (hopefully Feb 2022). I was going to do in December. However, my workload in Microsoft did not permit me to do that. I am also planning to set up a github repo so people can try out my changes, if they are interested. So, stay tuned. Madhavan
On Tue, Jan 25, 2022 at 05:21:27AM +0000, nobuta.keiya@fujitsu.com wrote: > I know that Julien Thierry published objtool support for arm64 [1], but I'm not > sure if it has been updated. Could you tell me other threads if you know? I've not heard of anyone else picking that up.
> >> I have not seen any activity on that in a long time. IIRC, Julien quit RedHat. > >> I don't know if anyone else has taken over this work in RedHat. > >> > >> Sorry, I don't have any more information. > >> > >> Madhavan > > > > Thanks for your information. > > > > By the way, I'm considering test code for arch_stack_walk_reliable(). > > Specifically, I apply Suraj's patch to enable livepatch, and added a function > > that sleeps between SYM_CODE_START and SYM_CODE_END, then livepatch > > checks if the task has an unreliable stack. > > For now my internal test code working correctly, but my Kconfig excludes > > STACK_VALIDATION dependency. > > > > It seems that objtool will not be enabled yet, so I would like to test it easier. > > If you are already testing with this patch, could you tell me how to do it? > > > > > > For now, I have an instrumented kernel that directly invokes arch_stack_walk_reliable() > from various places in the kernel (interrupt handlers, exception handlers, ftrace entry, > kprobe handler, etc). I also have a test driver to induce conditions like null pointer > dereference. I use this to test different cases where arch_stack_walk_reliable() should > return an error. That's good to know, thanks. > > As for livepatch testing, I have enhanced objtool and the kernel so the frame pointer can > be validated dynamically rather than statically. I have tested various different livepatch > selftests successfully. I have also written my own livepatch tests to add to the selftests. > I am currently working on preparing an RFC patch series for review. Basically, this series > implements STACK_VALIDATION in a different way. > > I plan to publish my work soon (hopefully Feb 2022). I was going to do in December. However, > my workload in Microsoft did not permit me to do that. I am also planning to set up a github > repo so people can try out my changes, if they are interested. > > So, stay tuned. > > Madhavan I'm very interested, so I would to be happy if you could tell me when the github repo is set up. Thanks again, Keiya
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index f6e333b59314..bc7b3514b563 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -223,6 +223,7 @@ config ARM64 select THREAD_INFO_IN_TASK select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD select TRACE_IRQFLAGS_SUPPORT + select HAVE_RELIABLE_STACKTRACE if FRAME_POINTER && STACK_VALIDATION help ARM 64-bit (AArch64) Linux support.