| Message ID | 20171002155638.GA18543@e107814-lin.cambridge.arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
The patch helps to overcome the issue, Probably it should be applied to all stable releases affected by this behaviour. modprobe in initrd may load quite required things. 2017-10-02 18:56 GMT+03:00 Suzuki K Poulose <Suzuki.Poulose@arm.com>: > On Mon, Oct 02, 2017 at 03:11:18PM +0100, James Morse wrote: >> Hi Matwey, >> >> On 02/10/17 12:24, Dave Martin wrote: >> > On Fri, Sep 29, 2017 at 10:23:54PM +0300, Matwey V. Kornilov wrote: >> >> I am running 4.13.3 on rockchip 3328 platform(aarch64) with glibc 2.26 >> >> and see the following at booting: >> >> >> >> [ 11.152061] modprobe[93]: undefined instruction: pc=0000ffff8ca48ff4 >> >> [ 11.152707] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >> >> [ 11.154347] modprobe[94]: undefined instruction: pc=0000ffff94243ff4 >> >> [ 11.154991] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >> >> [ 11.157070] modprobe[97]: undefined instruction: pc=0000ffff839a0ff4 >> >> [ 11.157715] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >> >> [ 11.159265] modprobe[98]: undefined instruction: pc=0000ffffb0591ff4 >> >> [ 11.159908] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >> >> >> >> As far as I understand d5380001 should be emulated in cpufeature.c but >> >> it is not. What could be wrong here? >> > >> > The whole sequence is >> > >> > 0: d503201f nop >> > 4: 8a180320 and x0, x25, x24 >> > 8: 92750001 and x1, x0, #0x800 >> > c: 365ffc20 tbz w0, #11, 0xffffffffffffff90 >> > 10:* d5380001 mrs x1, midr_el1 <-- trapping instruction >> >> This looks the same as: >> https://bugzilla.redhat.com/show_bug.cgi?id=1496209 >> >> [...] >> >> > What should happen here is that the do_undefinstr() in >> > arch/arm64/kernel/traps.c should call registered undef hooks until it >> > finds one that accepts the faulting instruction. >> > >> > So, either the cpufeatures undef hook is not getting called, or it is >> > failing the instruction somewhere, possibly in >> > cpufeatures.c:emulate_id_reg() or emulate_sys_reg(). >> > >> > >> > Can you add some trace to those functions to see what's happening? >> >> I couldn't reproduce this with linux-stable's v4.13.3 defconfig on Seattle or Juno. >> >> What distribution are you running? Could you also try [0] to see if this is >> something specific to your version of modprobe? > > > It is worth noting that we register the MRS instruction handler as late_init call. > Now the question is how late that could be. Given that we are hitting it with > modprobe, which could be used for requesting modules from initrd. Also which explains > why it we can't reproduce it by simple testcases, after it was registered. > > Now the question is, how early do we want to push this. Since it doesn't depend really > on any other subsystem, we could move it as early as "early". Or for keeping it in > line with other "arch" specific init calls, we could simply make it arch_initcall. > > Matwey, > > Please could you check if the following patch fixes the issue for you: > > Cheers > Suzuki > > ----8>---- > > arm64: Enable MRS emulation early enough in the boot sequence > > Make sure the MRS emulation is enabled early enough that the > early userspace applications (e.g, those run from initrd) could > run without any trouble. > > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index 9f9e0064c8c1..048f5469531f 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -1294,4 +1294,4 @@ static int __init enable_mrs_emulation(void) > return 0; > } > > -late_initcall(enable_mrs_emulation); > +arch_initcall(enable_mrs_emulation); > --- > > >> >> >> Thanks, >> >> James >> >> [0] works for me: >> ---------------------%<--------------------- >> #include <stdio.h> >> #include <sys/auxv.h> >> >> #ifndef HWCAP_CPUID >> #define HWCAP_CPUID (1 << 11) >> #endif >> >> int main(int argc, char **argv) >> { >> register unsigned int midr asm ("r1") = 0; >> unsigned long hwcaps = getauxval(AT_HWCAP); >> >> if (!(hwcaps & HWCAP_CPUID)) { >> fprintf(stderr, "mrs emulation not supported\n"); >> return 1; >> } >> >> asm("mrs %0, midr_el1" : "=r"(midr)); >> >> fprintf(stderr, "mrs x1, midr_el1; x1=0x%x\n", midr); >> >> return 0; >> } >> ---------------------%<--------------------- >>
Hi all, Hi Greg, On 10/04/2017 11:11 AM, Matwey V. Kornilov wrote: > The patch helps to overcome the issue, Probably it should be applied > to all stable releases affected by this behaviour. > modprobe in initrd may load quite required things. > > > 2017-10-02 18:56 GMT+03:00 Suzuki K Poulose <Suzuki.Poulose@arm.com>: >> On Mon, Oct 02, 2017 at 03:11:18PM +0100, James Morse wrote: >>> Hi Matwey, >>> >>> On 02/10/17 12:24, Dave Martin wrote: >>>> On Fri, Sep 29, 2017 at 10:23:54PM +0300, Matwey V. Kornilov wrote: >>>>> I am running 4.13.3 on rockchip 3328 platform(aarch64) with glibc 2.26 >>>>> and see the following at booting: >>>>> >>>>> [ 11.152061] modprobe[93]: undefined instruction: pc=0000ffff8ca48ff4 >>>>> [ 11.152707] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >>>>> [ 11.154347] modprobe[94]: undefined instruction: pc=0000ffff94243ff4 >>>>> [ 11.154991] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >>>>> [ 11.157070] modprobe[97]: undefined instruction: pc=0000ffff839a0ff4 >>>>> [ 11.157715] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >>>>> [ 11.159265] modprobe[98]: undefined instruction: pc=0000ffffb0591ff4 >>>>> [ 11.159908] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >>>>> >>>>> As far as I understand d5380001 should be emulated in cpufeature.c but >>>>> it is not. What could be wrong here? >>>> >>>> The whole sequence is >>>> >>>> 0: d503201f nop >>>> 4: 8a180320 and x0, x25, x24 >>>> 8: 92750001 and x1, x0, #0x800 >>>> c: 365ffc20 tbz w0, #11, 0xffffffffffffff90 >>>> 10:* d5380001 mrs x1, midr_el1 <-- trapping instruction >>> >>> This looks the same as: >>> https://bugzilla.redhat.com/show_bug.cgi?id=1496209 >>> >>> [...] >>> >>>> What should happen here is that the do_undefinstr() in >>>> arch/arm64/kernel/traps.c should call registered undef hooks until it >>>> finds one that accepts the faulting instruction. >>>> >>>> So, either the cpufeatures undef hook is not getting called, or it is >>>> failing the instruction somewhere, possibly in >>>> cpufeatures.c:emulate_id_reg() or emulate_sys_reg(). >>>> >>>> >>>> Can you add some trace to those functions to see what's happening? >>> >>> I couldn't reproduce this with linux-stable's v4.13.3 defconfig on Seattle or Juno. >>> >>> What distribution are you running? Could you also try [0] to see if this is >>> something specific to your version of modprobe? >> >> >> It is worth noting that we register the MRS instruction handler as late_init call. >> Now the question is how late that could be. Given that we are hitting it with >> modprobe, which could be used for requesting modules from initrd. Also which explains >> why it we can't reproduce it by simple testcases, after it was registered. >> >> Now the question is, how early do we want to push this. Since it doesn't depend really >> on any other subsystem, we could move it as early as "early". Or for keeping it in >> line with other "arch" specific init calls, we could simply make it arch_initcall. >> >> Matwey, >> >> Please could you check if the following patch fixes the issue for you: >> >> Cheers >> Suzuki >> >> ----8>---- >> >> arm64: Enable MRS emulation early enough in the boot sequence >> >> Make sure the MRS emulation is enabled early enough that the >> early userspace applications (e.g, those run from initrd) could >> run without any trouble. >> >> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> >> >> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c >> index 9f9e0064c8c1..048f5469531f 100644 >> --- a/arch/arm64/kernel/cpufeature.c >> +++ b/arch/arm64/kernel/cpufeature.c >> @@ -1294,4 +1294,4 @@ static int __init enable_mrs_emulation(void) >> return 0; >> } >> >> -late_initcall(enable_mrs_emulation); >> +arch_initcall(enable_mrs_emulation); >> --- >> >> I realized this patch did not land in v4.13.5 Did it got forgotten or are there any concerns? We also hit this bug in openSUSE Tumbleweed: https://bugzilla.suse.com/show_bug.cgi?id=1061188 Regards, Matthias >>> >>> >>> Thanks, >>> >>> James >>> >>> [0] works for me: >>> ---------------------%<--------------------- >>> #include <stdio.h> >>> #include <sys/auxv.h> >>> >>> #ifndef HWCAP_CPUID >>> #define HWCAP_CPUID (1 << 11) >>> #endif >>> >>> int main(int argc, char **argv) >>> { >>> register unsigned int midr asm ("r1") = 0; >>> unsigned long hwcaps = getauxval(AT_HWCAP); >>> >>> if (!(hwcaps & HWCAP_CPUID)) { >>> fprintf(stderr, "mrs emulation not supported\n"); >>> return 1; >>> } >>> >>> asm("mrs %0, midr_el1" : "=r"(midr)); >>> >>> fprintf(stderr, "mrs x1, midr_el1; x1=0x%x\n", midr); >>> >>> return 0; >>> } >>> ---------------------%<--------------------- >>> > > >
Hi Matthias, On Thu, Oct 05, 2017 at 04:54:09PM +0200, Matthias Brugger wrote: > On 10/04/2017 11:11 AM, Matwey V. Kornilov wrote: > >The patch helps to overcome the issue, Probably it should be applied > >to all stable releases affected by this behaviour. > >modprobe in initrd may load quite required things. > > > >2017-10-02 18:56 GMT+03:00 Suzuki K Poulose <Suzuki.Poulose@arm.com>: > >>arm64: Enable MRS emulation early enough in the boot sequence > >> > >>Make sure the MRS emulation is enabled early enough that the > >>early userspace applications (e.g, those run from initrd) could > >>run without any trouble. > >> > >>Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > >> > >>diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > >>index 9f9e0064c8c1..048f5469531f 100644 > >>--- a/arch/arm64/kernel/cpufeature.c > >>+++ b/arch/arm64/kernel/cpufeature.c > >>@@ -1294,4 +1294,4 @@ static int __init enable_mrs_emulation(void) > >> return 0; > >> } > >> > >>-late_initcall(enable_mrs_emulation); > >>+arch_initcall(enable_mrs_emulation); > >>--- > >> > >> > > I realized this patch did not land in v4.13.5 > Did it got forgotten or are there any concerns? This patch wasn't a complete fix, and the issue is still being discussed at: http://lists.infradead.org/pipermail/linux-arm-kernel/2017-October/534396.html Thanks, Mark.
Hi Matthias, On Thu, Oct 05, 2017 at 04:54:09PM +0200, Matthias Brugger wrote: > On 10/04/2017 11:11 AM, Matwey V. Kornilov wrote: > > The patch helps to overcome the issue, Probably it should be applied > > to all stable releases affected by this behaviour. > > modprobe in initrd may load quite required things. > > > > 2017-10-02 18:56 GMT+03:00 Suzuki K Poulose <Suzuki.Poulose@arm.com>: > > > On Mon, Oct 02, 2017 at 03:11:18PM +0100, James Morse wrote: > > > > On 02/10/17 12:24, Dave Martin wrote: > > > > > On Fri, Sep 29, 2017 at 10:23:54PM +0300, Matwey V. Kornilov wrote: > > > > > > I am running 4.13.3 on rockchip 3328 platform(aarch64) with glibc 2.26 > > > > > > and see the following at booting: > > > > > > > > > > > > [ 11.152061] modprobe[93]: undefined instruction: pc=0000ffff8ca48ff4 > > > > > > [ 11.152707] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) > > > > > > [ 11.154347] modprobe[94]: undefined instruction: pc=0000ffff94243ff4 > > > > > > [ 11.154991] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) > > > > > > [ 11.157070] modprobe[97]: undefined instruction: pc=0000ffff839a0ff4 > > > > > > [ 11.157715] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) > > > > > > [ 11.159265] modprobe[98]: undefined instruction: pc=0000ffffb0591ff4 > > > > > > [ 11.159908] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) > > > > > > > > > > > > As far as I understand d5380001 should be emulated in cpufeature.c but > > > > > > it is not. What could be wrong here? > > > > > > > > > > The whole sequence is > > > > > > > > > > 0: d503201f nop > > > > > 4: 8a180320 and x0, x25, x24 > > > > > 8: 92750001 and x1, x0, #0x800 > > > > > c: 365ffc20 tbz w0, #11, 0xffffffffffffff90 > > > > > 10:* d5380001 mrs x1, midr_el1 <-- trapping instruction > > > > > > > > This looks the same as: > > > > https://bugzilla.redhat.com/show_bug.cgi?id=1496209 > > > > > > > > [...] > > > > > > > > > What should happen here is that the do_undefinstr() in > > > > > arch/arm64/kernel/traps.c should call registered undef hooks until it > > > > > finds one that accepts the faulting instruction. > > > > > > > > > > So, either the cpufeatures undef hook is not getting called, or it is > > > > > failing the instruction somewhere, possibly in > > > > > cpufeatures.c:emulate_id_reg() or emulate_sys_reg(). > > > > > > > > > > > > > > > Can you add some trace to those functions to see what's happening? > > > > > > > > I couldn't reproduce this with linux-stable's v4.13.3 defconfig on Seattle or Juno. > > > > > > > > What distribution are you running? Could you also try [0] to see if this is > > > > something specific to your version of modprobe? > > > > > > > > > It is worth noting that we register the MRS instruction handler as late_init call. > > > Now the question is how late that could be. Given that we are hitting it with > > > modprobe, which could be used for requesting modules from initrd. Also which explains > > > why it we can't reproduce it by simple testcases, after it was registered. > > > > > > Now the question is, how early do we want to push this. Since it doesn't depend really > > > on any other subsystem, we could move it as early as "early". Or for keeping it in > > > line with other "arch" specific init calls, we could simply make it arch_initcall. > > > > > > Matwey, > > > > > > Please could you check if the following patch fixes the issue for you: > > > > > > Cheers > > > Suzuki > > > > > > ----8>---- > > > > > > arm64: Enable MRS emulation early enough in the boot sequence > > > > > > Make sure the MRS emulation is enabled early enough that the > > > early userspace applications (e.g, those run from initrd) could > > > run without any trouble. > > > > > > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > > > > > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > > > index 9f9e0064c8c1..048f5469531f 100644 > > > --- a/arch/arm64/kernel/cpufeature.c > > > +++ b/arch/arm64/kernel/cpufeature.c > > > @@ -1294,4 +1294,4 @@ static int __init enable_mrs_emulation(void) > > > return 0; > > > } > > > > > > -late_initcall(enable_mrs_emulation); > > > +arch_initcall(enable_mrs_emulation); > > > --- > > I realized this patch did not land in v4.13.5 > Did it got forgotten or are there any concerns? > > We also hit this bug in openSUSE Tumbleweed: > https://bugzilla.suse.com/show_bug.cgi?id=1061188 As Mark replied, we are still debating why this happens and whether the above fix is sufficient. As we were digging further, we realised there is no clear init level after which user space can be invoked, which means Suzuki's patch may not always be sufficient. I proposed something as a way of spotting this issue early [1] but I need to post it on the linux-arch to get some consensus. Can you post the full kernel log somewhere? I'm trying to figure out what trigged the modprobe during the kernel boot. Thanks, Catalin [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2017-October/534465.html
Hi Catalin, On 10/05/2017 06:16 PM, Catalin Marinas wrote: > Hi Matthias, > > On Thu, Oct 05, 2017 at 04:54:09PM +0200, Matthias Brugger wrote: >> On 10/04/2017 11:11 AM, Matwey V. Kornilov wrote: >>> The patch helps to overcome the issue, Probably it should be applied >>> to all stable releases affected by this behaviour. >>> modprobe in initrd may load quite required things. >>> >>> 2017-10-02 18:56 GMT+03:00 Suzuki K Poulose <Suzuki.Poulose@arm.com>: >>>> On Mon, Oct 02, 2017 at 03:11:18PM +0100, James Morse wrote: >>>>> On 02/10/17 12:24, Dave Martin wrote: >>>>>> On Fri, Sep 29, 2017 at 10:23:54PM +0300, Matwey V. Kornilov wrote: >>>>>>> I am running 4.13.3 on rockchip 3328 platform(aarch64) with glibc 2.26 >>>>>>> and see the following at booting: >>>>>>> >>>>>>> [ 11.152061] modprobe[93]: undefined instruction: pc=0000ffff8ca48ff4 >>>>>>> [ 11.152707] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >>>>>>> [ 11.154347] modprobe[94]: undefined instruction: pc=0000ffff94243ff4 >>>>>>> [ 11.154991] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >>>>>>> [ 11.157070] modprobe[97]: undefined instruction: pc=0000ffff839a0ff4 >>>>>>> [ 11.157715] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >>>>>>> [ 11.159265] modprobe[98]: undefined instruction: pc=0000ffffb0591ff4 >>>>>>> [ 11.159908] Code: d503201f 8a180320 92750001 365ffc20 (d5380001) >>>>>>> >>>>>>> As far as I understand d5380001 should be emulated in cpufeature.c but >>>>>>> it is not. What could be wrong here? >>>>>> >>>>>> The whole sequence is >>>>>> >>>>>> 0: d503201f nop >>>>>> 4: 8a180320 and x0, x25, x24 >>>>>> 8: 92750001 and x1, x0, #0x800 >>>>>> c: 365ffc20 tbz w0, #11, 0xffffffffffffff90 >>>>>> 10:* d5380001 mrs x1, midr_el1 <-- trapping instruction >>>>> >>>>> This looks the same as: >>>>> https://bugzilla.redhat.com/show_bug.cgi?id=1496209 >>>>> >>>>> [...] >>>>> >>>>>> What should happen here is that the do_undefinstr() in >>>>>> arch/arm64/kernel/traps.c should call registered undef hooks until it >>>>>> finds one that accepts the faulting instruction. >>>>>> >>>>>> So, either the cpufeatures undef hook is not getting called, or it is >>>>>> failing the instruction somewhere, possibly in >>>>>> cpufeatures.c:emulate_id_reg() or emulate_sys_reg(). >>>>>> >>>>>> >>>>>> Can you add some trace to those functions to see what's happening? >>>>> >>>>> I couldn't reproduce this with linux-stable's v4.13.3 defconfig on Seattle or Juno. >>>>> >>>>> What distribution are you running? Could you also try [0] to see if this is >>>>> something specific to your version of modprobe? >>>> >>>> >>>> It is worth noting that we register the MRS instruction handler as late_init call. >>>> Now the question is how late that could be. Given that we are hitting it with >>>> modprobe, which could be used for requesting modules from initrd. Also which explains >>>> why it we can't reproduce it by simple testcases, after it was registered. >>>> >>>> Now the question is, how early do we want to push this. Since it doesn't depend really >>>> on any other subsystem, we could move it as early as "early". Or for keeping it in >>>> line with other "arch" specific init calls, we could simply make it arch_initcall. >>>> >>>> Matwey, >>>> >>>> Please could you check if the following patch fixes the issue for you: >>>> >>>> Cheers >>>> Suzuki >>>> >>>> ----8>---- >>>> >>>> arm64: Enable MRS emulation early enough in the boot sequence >>>> >>>> Make sure the MRS emulation is enabled early enough that the >>>> early userspace applications (e.g, those run from initrd) could >>>> run without any trouble. >>>> >>>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> >>>> >>>> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c >>>> index 9f9e0064c8c1..048f5469531f 100644 >>>> --- a/arch/arm64/kernel/cpufeature.c >>>> +++ b/arch/arm64/kernel/cpufeature.c >>>> @@ -1294,4 +1294,4 @@ static int __init enable_mrs_emulation(void) >>>> return 0; >>>> } >>>> >>>> -late_initcall(enable_mrs_emulation); >>>> +arch_initcall(enable_mrs_emulation); >>>> --- >> >> I realized this patch did not land in v4.13.5 >> Did it got forgotten or are there any concerns? >> >> We also hit this bug in openSUSE Tumbleweed: >> https://bugzilla.suse.com/show_bug.cgi?id=1061188 > > As Mark replied, we are still debating why this happens and whether the > above fix is sufficient. As we were digging further, we realised there > is no clear init level after which user space can be invoked, which > means Suzuki's patch may not always be sufficient. > > I proposed something as a way of spotting this issue early [1] but I > need to post it on the linux-arch to get some consensus. > > Can you post the full kernel log somewhere? I'm trying to figure out > what trigged the modprobe during the kernel boot. > You can find the kernel log here: https://bugzilla.suse.com/attachment.cgi?id=743311 Regards, Matthias > Thanks, > > Catalin > > [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2017-October/534465.html >
On Fri, Oct 06, 2017 at 02:05:09PM +0200, Matthias Brugger wrote: > On 10/05/2017 06:16 PM, Catalin Marinas wrote: > > On Thu, Oct 05, 2017 at 04:54:09PM +0200, Matthias Brugger wrote: > > > We also hit this bug in openSUSE Tumbleweed: > > > https://bugzilla.suse.com/show_bug.cgi?id=1061188 > > > > As Mark replied, we are still debating why this happens and whether the > > above fix is sufficient. As we were digging further, we realised there > > is no clear init level after which user space can be invoked, which > > means Suzuki's patch may not always be sufficient. > > > > I proposed something as a way of spotting this issue early [1] but I > > need to post it on the linux-arch to get some consensus. > > > > Can you post the full kernel log somewhere? I'm trying to figure out > > what trigged the modprobe during the kernel boot. > > > > You can find the kernel log here: > https://bugzilla.suse.com/attachment.cgi?id=743311 Thanks, it seems that ipv6 module loading triggered this. Talking to Suzuki, we came to the conclusion that such thing cannot happen before rootfs_initcall, so his original core_initcall change should suffice. I'll push a patch out, hopefully for -rc4 and cc stable.
On 10/06/2017 03:13 PM, Catalin Marinas wrote: > On Fri, Oct 06, 2017 at 02:05:09PM +0200, Matthias Brugger wrote: >> On 10/05/2017 06:16 PM, Catalin Marinas wrote: >>> On Thu, Oct 05, 2017 at 04:54:09PM +0200, Matthias Brugger wrote: >>>> We also hit this bug in openSUSE Tumbleweed: >>>> https://bugzilla.suse.com/show_bug.cgi?id=1061188 >>> >>> As Mark replied, we are still debating why this happens and whether the >>> above fix is sufficient. As we were digging further, we realised there >>> is no clear init level after which user space can be invoked, which >>> means Suzuki's patch may not always be sufficient. >>> >>> I proposed something as a way of spotting this issue early [1] but I >>> need to post it on the linux-arch to get some consensus. >>> >>> Can you post the full kernel log somewhere? I'm trying to figure out >>> what trigged the modprobe during the kernel boot. >>> >> >> You can find the kernel log here: >> https://bugzilla.suse.com/attachment.cgi?id=743311 > > Thanks, it seems that ipv6 module loading triggered this. > > Talking to Suzuki, we came to the conclusion that such thing cannot > happen before rootfs_initcall, so his original core_initcall change > should suffice. I'll push a patch out, hopefully for -rc4 and cc stable. > Thanks for the info. Matthias
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 9f9e0064c8c1..048f5469531f 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1294,4 +1294,4 @@ static int __init enable_mrs_emulation(void) return 0; } -late_initcall(enable_mrs_emulation); +arch_initcall(enable_mrs_emulation);