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Re: [x86] 811565123a: BUG: kernel hang in early-boot stage, last printk: Probing EDD (edd=off to disable)... ok

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  Re: [x86]  811565123a: BUG: kernel hang in early-boot stage, last printk: Probing EDD (edd=off to disable)... ok Andi Kleen <andi@firstfloor.org> - 2016-10-13 22:40 +0200
    Re: [x86]  811565123a: BUG: kernel hang in early-boot stage, last  printk: Probing EDD (edd=off to disable)... ok Ye Xiaolong <xiaolong.ye@intel.com> - 2016-10-14 03:00 +0200
    Re: [x86]  811565123a: BUG: kernel hang in early-boot stage, last  printk: Probing EDD (edd=off to disable)... ok Ye Xiaolong <xiaolong.ye@intel.com> - 2016-10-14 03:00 +0200
      Re: [LKP] [x86]  811565123a: BUG: kernel hang in early-boot stage,  last printk: Probing EDD (edd=off to disable)... ok Ye Xiaolong <xiaolong.ye@intel.com> - 2016-10-14 07:00 +0200
        Re: [LKP] [x86]  811565123a: BUG: kernel hang in early-boot stage,  last printk: Probing EDD (edd=off to disable)... ok Andi Kleen <andi@firstfloor.org> - 2016-10-14 23:00 +0200
          Re: [LKP] [x86]  811565123a: BUG: kernel hang in early-boot stage,  last printk: Probing EDD (edd=off to disable)... ok Ye Xiaolong <xiaolong.ye@intel.com> - 2016-10-17 04:00 +0200

#1500543 — Re: [x86] 811565123a: BUG: kernel hang in early-boot stage, last printk: Probing EDD (edd=off to disable)... ok

Andi Kleen <andi@firstfloor.org> writes:

Any comments on this?

I still cannot reproduce the failure unfortunately.


> Could you do two tests for me:
>
> - Enable CONFIG_MICROCODE_INTEL and see if it boots then
>
> - Add CONFIG_DEBUG_INFO to the config.
> Add -s to the qemu command line and boot again. Then when it hangs 
> connect gdb to see where it hangs
>
> gdb -ex "target remote localhost:1234" vmlinux
> bt
>
> <show output>

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#1500653 — Re: [x86] 811565123a: BUG: kernel hang in early-boot stage, last printk: Probing EDD (edd=off to disable)... ok

On 10/13, Andi Kleen wrote:
>Andi Kleen <andi@firstfloor.org> writes:
>
>Any comments on this?
>
>I still cannot reproduce the failure unfortunately.

oh, sorry, missed you mail before, I'll try the tests you mentioned and
provide results later.

Thanks,
Xiaolong

>
>
>> Could you do two tests for me:
>>
>> - Enable CONFIG_MICROCODE_INTEL and see if it boots then
>>
>> - Add CONFIG_DEBUG_INFO to the config.
>> Add -s to the qemu command line and boot again. Then when it hangs 
>> connect gdb to see where it hangs
>>
>> gdb -ex "target remote localhost:1234" vmlinux
>> bt
>>
>> <show output>

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#1500655 — Re: [x86] 811565123a: BUG: kernel hang in early-boot stage, last printk: Probing EDD (edd=off to disable)... ok

On 10/13, Andi Kleen wrote:
>Andi Kleen <andi@firstfloor.org> writes:
>
>Any comments on this?
>
>I still cannot reproduce the failure unfortunately.
>

Btw, you can try below commands to reproduce the error on your local
host, they will download the necessary images and run QEMU:

       git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
       cd lkp-tests
       bin/lkp qemu -k KERNEL job-script  # job-script is attached in the original report email

Thanks,
Xiaolong
>
>> Could you do two tests for me:
>>
>> - Enable CONFIG_MICROCODE_INTEL and see if it boots then
>>
>> - Add CONFIG_DEBUG_INFO to the config.
>> Add -s to the qemu command line and boot again. Then when it hangs 
>> connect gdb to see where it hangs
>>
>> gdb -ex "target remote localhost:1234" vmlinux
>> bt
>>
>> <show output>

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#1500695 — Re: [LKP] [x86] 811565123a: BUG: kernel hang in early-boot stage, last printk: Probing EDD (edd=off to disable)... ok

On 10/14, Ye Xiaolong wrote:
>On 10/13, Andi Kleen wrote:
>>Andi Kleen <andi@firstfloor.org> writes:
>>
>>Any comments on this?
>>
>>I still cannot reproduce the failure unfortunately.
>>
>
>Btw, you can try below commands to reproduce the error on your local
>host, they will download the necessary images and run QEMU:
>
>       git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
>       cd lkp-tests
>       bin/lkp qemu -k KERNEL job-script  # job-script is attached in the original report email

Results show this hang may be related to gcc version, with gcc version
4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3), kernel could boot without early
hang, but if kernel was built with gcc version 6.2.0 20160901 (Debian
6.2.0-3), it will stuck in the early stage:

early console in setup code
Probing EDD (edd=off to disable)... ok


gdb output as below:

$ gdb -ex "target remote localhost:1234" vmlinux 
GNU gdb (Ubuntu 7.7.1-0ubuntu5~14.04.2) 7.7.1
Copyright (C) 2014 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from vmlinux...done.
Remote debugging using localhost:1234
0x048a34d9 in ?? ()
(gdb) bt
#0  0x048a34d9 in ?? ()
#1  0x00000000 in ?? ()
(gdb) 


Thanks,
Xiaolong
>
>Thanks,
>Xiaolong
>>
>>> Could you do two tests for me:
>>>
>>> - Enable CONFIG_MICROCODE_INTEL and see if it boots then
>>>
>>> - Add CONFIG_DEBUG_INFO to the config.
>>> Add -s to the qemu command line and boot again. Then when it hangs 
>>> connect gdb to see where it hangs
>>>
>>> gdb -ex "target remote localhost:1234" vmlinux
>>> bt
>>>
>>> <show output>
>_______________________________________________
>LKP mailing list
>LKP@lists.01.org
>https://lists.01.org/mailman/listinfo/lkp

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#1501192 — Re: [LKP] [x86] 811565123a: BUG: kernel hang in early-boot stage, last printk: Probing EDD (edd=off to disable)... ok

On Fri, Oct 14, 2016 at 12:56:00PM +0800, Ye Xiaolong wrote:
> On 10/14, Ye Xiaolong wrote:
> >On 10/13, Andi Kleen wrote:
> >>Andi Kleen <andi@firstfloor.org> writes:
> >>
> >>Any comments on this?
> >>
> >>I still cannot reproduce the failure unfortunately.
> >>
> >
> >Btw, you can try below commands to reproduce the error on your local
> >host, they will download the necessary images and run QEMU:
> >
> >       git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
> >       cd lkp-tests
> >       bin/lkp qemu -k KERNEL job-script  # job-script is attached in the original report email
> 
> Results show this hang may be related to gcc version, with gcc version
> 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3), kernel could boot without early
> hang, but if kernel was built with gcc version 6.2.0 20160901 (Debian
> 6.2.0-3), it will stuck in the early stage:

I built a mainline gcc 6.2, unfortunately still doesn't reproduce. The kernel
with your config boots to root.

My guess is that something is broken with paravirt ops on 32bit
on that compiler.

I created a new patch with the probing code moved to a separate
function. Can you test if that works?

-Andi


commit 65c92de6678f04ce14b237d7073e164b98d9a8be
Author: Andi Kleen <ak@linux.intel.com>
Date:   Wed May 4 06:07:44 2016 -0700

    x86: Report Intel platform_id in /proc/cpuinfo
    
    We have a need to distinguish systems based on their platform ID.
    For example this is useful to distinguish systems with L4 cache
    versus ones without.
    
    There is a 3 bit identifier (also called processor flags) in
    the IA32_PLATFORM_ID MSR that can give a more fine grained
    identification of the CPU than just the model number/stepping.
    
    IA32_PLATFORM_ID is architectural.
    
    The MSR can be also accessed through /dev/cpu/*/msr, but that
    requires root and is awkward.
    
    The patch moves the reading of PLATFORM_INFO from the
    (late) microcode driver code into the main intel CPU initialization
    path and then also prints it in /proc/cpuinfo
    
    v2: Handle 0 platform_id. Fix commit message.
    v3: Move some code to cpu/intel.c
    v4: Update description too.
    v5: Move msr probe code out of line to w/a potential gcc 6 bug
    Cc: hmh@hmh.eng.br
    Signed-off-by: Andi Kleen <ak@linux.intel.com>

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 63def9537a2d..c1313b3f3e59 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -135,6 +135,8 @@ struct cpuinfo_x86 {
 	/* Index into per_cpu list: */
 	u16			cpu_index;
 	u32			microcode;
+	u32			platform_id;
+	u8			has_platform_id;
 };
 
 #define X86_VENDOR_INTEL	0
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index fcd484d2bb03..7da7f008cee0 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -61,6 +61,19 @@ void check_mpx_erratum(struct cpuinfo_x86 *c)
 	}
 }
 
+/* noinline to work around problem with gcc 6.2 */
+static noinline void probe_platformid(struct cpuinfo_x86 *c)
+{
+	if ((c->x86_model >= 5) || (c->x86 > 6)) {
+		unsigned val[2];
+
+		/* get processor flags from MSR 0x17 */
+		rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
+		c->platform_id = (val[1] >> 18) & 7;
+		c->has_platform_id = true;
+	}
+}
+
 static void early_init_intel(struct cpuinfo_x86 *c)
 {
 	u64 misc_enable;
@@ -211,6 +224,8 @@ static void early_init_intel(struct cpuinfo_x86 *c)
 	}
 
 	check_mpx_erratum(c);
+
+	probe_platformid(c);
 }
 
 #ifdef CONFIG_X86_32
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index cdc0deab00c9..fab07e49192e 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -855,17 +855,13 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
 {
 	static struct cpu_signature prev;
 	struct cpuinfo_x86 *c = &cpu_data(cpu_num);
-	unsigned int val[2];
 
 	memset(csig, 0, sizeof(*csig));
 
 	csig->sig = cpuid_eax(0x00000001);
 
-	if ((c->x86_model >= 5) || (c->x86 > 6)) {
-		/* get processor flags from MSR 0x17 */
-		rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
-		csig->pf = 1 << ((val[1] >> 18) & 7);
-	}
+	if (c->has_platform_id)
+		csig->pf = 1 << c->platform_id;
 
 	csig->rev = c->microcode;
 
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 18ca99f2798b..5345d50ed709 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -76,6 +76,8 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 		seq_puts(m, "stepping\t: unknown\n");
 	if (c->microcode)
 		seq_printf(m, "microcode\t: 0x%x\n", c->microcode);
+	if (c->has_platform_id)
+		seq_printf(m, "platform_id\t: %d\n", c->platform_id);
 
 	if (cpu_has(c, X86_FEATURE_TSC)) {
 		unsigned int freq = cpufreq_quick_get(cpu);

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#1501595 — Re: [LKP] [x86] 811565123a: BUG: kernel hang in early-boot stage, last printk: Probing EDD (edd=off to disable)... ok

On 10/14, Andi Kleen wrote:
>On Fri, Oct 14, 2016 at 12:56:00PM +0800, Ye Xiaolong wrote:
>> On 10/14, Ye Xiaolong wrote:
>> >On 10/13, Andi Kleen wrote:
>> >>Andi Kleen <andi@firstfloor.org> writes:
>> >>
>> >>Any comments on this?
>> >>
>> >>I still cannot reproduce the failure unfortunately.
>> >>
>> >
>> >Btw, you can try below commands to reproduce the error on your local
>> >host, they will download the necessary images and run QEMU:
>> >
>> >       git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
>> >       cd lkp-tests
>> >       bin/lkp qemu -k KERNEL job-script  # job-script is attached in the original report email
>> 
>> Results show this hang may be related to gcc version, with gcc version
>> 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3), kernel could boot without early
>> hang, but if kernel was built with gcc version 6.2.0 20160901 (Debian
>> 6.2.0-3), it will stuck in the early stage:
>
>I built a mainline gcc 6.2, unfortunately still doesn't reproduce. The kernel
>with your config boots to root.
>
>My guess is that something is broken with paravirt ops on 32bit
>on that compiler.
>
>I created a new patch with the probing code moved to a separate
>function. Can you test if that works?
>

Kernel can boot to root with this new version patch.

Tested-by: Xiaolong Ye <xiaolong.ye@intel.com>


Thanks,
Xiaolong


>-Andi
>
>
>commit 65c92de6678f04ce14b237d7073e164b98d9a8be
>Author: Andi Kleen <ak@linux.intel.com>
>Date:   Wed May 4 06:07:44 2016 -0700
>
>    x86: Report Intel platform_id in /proc/cpuinfo
>    
>    We have a need to distinguish systems based on their platform ID.
>    For example this is useful to distinguish systems with L4 cache
>    versus ones without.
>    
>    There is a 3 bit identifier (also called processor flags) in
>    the IA32_PLATFORM_ID MSR that can give a more fine grained
>    identification of the CPU than just the model number/stepping.
>    
>    IA32_PLATFORM_ID is architectural.
>    
>    The MSR can be also accessed through /dev/cpu/*/msr, but that
>    requires root and is awkward.
>    
>    The patch moves the reading of PLATFORM_INFO from the
>    (late) microcode driver code into the main intel CPU initialization
>    path and then also prints it in /proc/cpuinfo
>    
>    v2: Handle 0 platform_id. Fix commit message.
>    v3: Move some code to cpu/intel.c
>    v4: Update description too.
>    v5: Move msr probe code out of line to w/a potential gcc 6 bug
>    Cc: hmh@hmh.eng.br
>    Signed-off-by: Andi Kleen <ak@linux.intel.com>
>
>diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
>index 63def9537a2d..c1313b3f3e59 100644
>--- a/arch/x86/include/asm/processor.h
>+++ b/arch/x86/include/asm/processor.h
>@@ -135,6 +135,8 @@ struct cpuinfo_x86 {
> 	/* Index into per_cpu list: */
> 	u16			cpu_index;
> 	u32			microcode;
>+	u32			platform_id;
>+	u8			has_platform_id;
> };
> 
> #define X86_VENDOR_INTEL	0
>diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
>index fcd484d2bb03..7da7f008cee0 100644
>--- a/arch/x86/kernel/cpu/intel.c
>+++ b/arch/x86/kernel/cpu/intel.c
>@@ -61,6 +61,19 @@ void check_mpx_erratum(struct cpuinfo_x86 *c)
> 	}
> }
> 
>+/* noinline to work around problem with gcc 6.2 */
>+static noinline void probe_platformid(struct cpuinfo_x86 *c)
>+{
>+	if ((c->x86_model >= 5) || (c->x86 > 6)) {
>+		unsigned val[2];
>+
>+		/* get processor flags from MSR 0x17 */
>+		rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
>+		c->platform_id = (val[1] >> 18) & 7;
>+		c->has_platform_id = true;
>+	}
>+}
>+
> static void early_init_intel(struct cpuinfo_x86 *c)
> {
> 	u64 misc_enable;
>@@ -211,6 +224,8 @@ static void early_init_intel(struct cpuinfo_x86 *c)
> 	}
> 
> 	check_mpx_erratum(c);
>+
>+	probe_platformid(c);
> }
> 
> #ifdef CONFIG_X86_32
>diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
>index cdc0deab00c9..fab07e49192e 100644
>--- a/arch/x86/kernel/cpu/microcode/intel.c
>+++ b/arch/x86/kernel/cpu/microcode/intel.c
>@@ -855,17 +855,13 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
> {
> 	static struct cpu_signature prev;
> 	struct cpuinfo_x86 *c = &cpu_data(cpu_num);
>-	unsigned int val[2];
> 
> 	memset(csig, 0, sizeof(*csig));
> 
> 	csig->sig = cpuid_eax(0x00000001);
> 
>-	if ((c->x86_model >= 5) || (c->x86 > 6)) {
>-		/* get processor flags from MSR 0x17 */
>-		rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
>-		csig->pf = 1 << ((val[1] >> 18) & 7);
>-	}
>+	if (c->has_platform_id)
>+		csig->pf = 1 << c->platform_id;
> 
> 	csig->rev = c->microcode;
> 
>diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
>index 18ca99f2798b..5345d50ed709 100644
>--- a/arch/x86/kernel/cpu/proc.c
>+++ b/arch/x86/kernel/cpu/proc.c
>@@ -76,6 +76,8 @@ static int show_cpuinfo(struct seq_file *m, void *v)
> 		seq_puts(m, "stepping\t: unknown\n");
> 	if (c->microcode)
> 		seq_printf(m, "microcode\t: 0x%x\n", c->microcode);
>+	if (c->has_platform_id)
>+		seq_printf(m, "platform_id\t: %d\n", c->platform_id);
> 
> 	if (cpu_has(c, X86_FEATURE_TSC)) {
> 		unsigned int freq = cpufreq_quick_get(cpu);

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