From: Matwey V. Kornilov <hidden> Date: 2017-09-29 19:23:54
Hello,
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?
--
With best regards,
Matwey V. Kornilov
On Fri, Sep 29, 2017 at 10:23:54PM +0300, Matwey V. Kornilov wrote:
Hello,
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
I'm _guessing_ this is the glibc startup code, or otherwise something
similar:
http://www.sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/cpu-features.c;h=0275d11c7fa5cba02f3173db25a8a02993e92b7e;hb=1c9a5c270d8b66f30dcfaf1cb2d6cf39d3e18369#l46
The emulation is not guaranteed to work if HWCAP_CPUID (1 << 11) is not
set, but this code does seem to be checking correctly, and v4.13 should
unconditionally set this hwcap and emulate MRS.
So no, I don't know what's going wrong here.
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?
Cc'ing Suzuki, who knows this code better than me and may have some
ideas.
Cheers
---Dave
On Fri, Sep 29, 2017 at 10:23:54PM +0300, Matwey V. Kornilov wrote:
quoted
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
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?
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;
}
---------------------%<---------------------
From: Suzuki.Poulose@arm.com (Suzuki K Poulose) Date: 2017-10-02 15:56:39
On Mon, Oct 02, 2017 at 03:11:18PM +0100, James Morse wrote:
Hi Matwey,
On 02/10/17 12:24, Dave Martin wrote:
quoted
On Fri, Sep 29, 2017 at 10:23:54PM +0300, Matwey V. Kornilov wrote:
quoted
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
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>
From: Matwey V. Kornilov <hidden> Date: 2017-10-04 09:11:16
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 [off-list ref]:
quoted hunk
On Mon, Oct 02, 2017 at 03:11:18PM +0100, James Morse wrote:
quoted
Hi Matwey,
On 02/10/17 12:24, Dave Martin wrote:
quoted
On Fri, Sep 29, 2017 at 10:23:54PM +0300, Matwey V. Kornilov wrote:
quoted
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
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>
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 [off-list ref]:
quoted
On Mon, Oct 02, 2017 at 03:11:18PM +0100, James Morse wrote:
quoted
Hi Matwey,
On 02/10/17 12:24, Dave Martin wrote:
quoted
On Fri, Sep 29, 2017 at 10:23:54PM +0300, Matwey V. Kornilov wrote:
quoted
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
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>
@@ -1294,4 +1294,4 @@ static int __init enable_mrs_emulation(void)return0;}-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
quoted
quoted
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:
quoted
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 [off-list ref]:
quoted
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>
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:
quoted
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 [off-list ref]:
quoted
On Mon, Oct 02, 2017 at 03:11:18PM +0100, James Morse wrote:
quoted
On 02/10/17 12:24, Dave Martin wrote:
quoted
On Fri, Sep 29, 2017 at 10:23:54PM +0300, Matwey V. Kornilov wrote:
quoted
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
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>
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:
quoted
On 10/04/2017 11:11 AM, Matwey V. Kornilov wrote:
quoted
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 [off-list ref]:
quoted
On Mon, Oct 02, 2017 at 03:11:18PM +0100, James Morse wrote:
quoted
On 02/10/17 12:24, Dave Martin wrote:
quoted
On Fri, Sep 29, 2017 at 10:23:54PM +0300, Matwey V. Kornilov wrote:
quoted
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
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>
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.
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, 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.
--
Catalin
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, 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.