Re: [PATCH 4.14 023/159] mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y

Baoquan He
2018-02-07T11:28:18Z

On 02/07/18 at 05:25pm, Dou Liyang wrote:
> Hi All,
>
> I met the makedumpfile failed in the upstream kernel which contained
> this patch. Did I missed something else?

readmem: Can't convert a virtual address(ffff88007ffd7000) to physical

Should not related to this patch. Otherwise your code can't get to that
step. From message, ffff88007ffd7000 is the end of the last mem region,
seems a code bug. You are testing 5-level on makedumpfile, right?

The patches I posted to descrease the memmory cost on mem map allocation
has code bug, Fengguang's test robot sent a mail to me, I have updated
patches, try to write a good patch log. You might also need check the
5-level patches you posted to makedumpfile upstream.

>
> In fedora27 host:
>
> [douly@localhost code]$ ./makedumpfile -d 31 --message-level 31 -x
> vmlinux_4.15+ vmcore_4.15+_from_cp_command vmcore_4.15+
>
> sadump: does not have partition header
> sadump: read dump device as unknown format
> sadump: unknown format
> LOAD (0)
> phys_start : 1000000
> phys_end : 2a86000
> virt_start : ffffffff81000000
> virt_end : ffffffff82a86000
> LOAD (1)
> phys_start : 1000
> phys_end : 9fc00
> virt_start : ffff880000001000
> virt_end : ffff88000009fc00
> LOAD (2)
> phys_start : 100000
> phys_end : 13000000
> virt_start : ffff880000100000
> virt_end : ffff880013000000
> LOAD (3)
> phys_start : 33000000
> phys_end : 7ffd7000
> virt_start : ffff880033000000
> virt_end : ffff88007ffd7000
> Linux kdump
> page_size : 4096
>
> max_mapnr : 7ffd7
>
> Buffer size for the cyclic mode: 131061
> The kernel version is not supported.
> The makedumpfile operation may be incomplete.
>
> num of NODEs : 1
>
>
> Memory type : SPARSEMEM_EX
>
> mem_map (0)
> mem_map : ffff88007ff26000
> pfn_start : 0
> pfn_end : 8000
> mem_map (1)
> mem_map : 0
> pfn_start : 8000
> pfn_end : 10000
> mem_map (2)
> mem_map : 0
> pfn_start : 10000
> pfn_end : 18000
> mem_map (3)
> mem_map : 0
> pfn_start : 18000
> pfn_end : 20000
> mem_map (4)
> mem_map : 0
> pfn_start : 20000
> pfn_end : 28000
> mem_map (5)
> mem_map : 0
> pfn_start : 28000
> pfn_end : 30000
> mem_map (6)
> mem_map : 0
> pfn_start : 30000
> pfn_end : 38000
> mem_map (7)
> mem_map : 0
> pfn_start : 38000
> pfn_end : 40000
> mem_map (8)
> mem_map : 0
> pfn_start : 40000
> pfn_end : 48000
> mem_map (9)
> mem_map : 0
> pfn_start : 48000
> pfn_end : 50000
> mem_map (10)
> mem_map : 0
> pfn_start : 50000
> pfn_end : 58000
> mem_map (11)
> mem_map : 0
> pfn_start : 58000
> pfn_end : 60000
> mem_map (12)
> mem_map : 0
> pfn_start : 60000
> pfn_end : 68000
> mem_map (13)
> mem_map : 0
> pfn_start : 68000
> pfn_end : 70000
> mem_map (14)
> mem_map : 0
> pfn_start : 70000
> pfn_end : 78000
> mem_map (15)
> mem_map : 0
> pfn_start : 78000
> pfn_end : 7ffd7
> mmap() is available on the kernel.
> Checking for memory holes : [100.0 %] | STEP
> [Checking for memory holes ] : 0.000060 seconds
> __vtop4_x86_64: Can't get a valid pte.
> readmem: Can't convert a virtual address(ffff88007ffd7000) to physical
> address.
> readmem: type_addr: 0, addr:ffff88007ffd7000, size:32768
> __exclude_unnecessary_pages: Can't read the buffer of struct page.
> create_2nd_bitmap: Can't exclude unnecessary pages.
> Checking for memory holes : [100.0 %] \ STEP
> [Checking for memory holes ] : 0.000010 seconds
> Checking for memory holes : [100.0 %] - STEP
> [Checking for memory holes ] : 0.000004 seconds
> __vtop4_x86_64: Can't get a valid pte.
> readmem: Can't convert a virtual address(ffff88007ffd7000) to physical
> address.
> readmem: type_addr: 0, addr:ffff88007ffd7000, size:32768
> __exclude_unnecessary_pages: Can't read the buffer of struct page.
> create_2nd_bitmap: Can't exclude unnecessary pages.
>
> Thanks,
> dou
> At 01/09/2018 11:44 AM, Mike Galbraith wrote:
> > On Tue, 2018-01-09 at 03:13 +0300, Kirill A. Shutemov wrote:
> > >
> > > Mike, could you test this? (On top of the rest of the fixes.)
> >
> > homer:..crash/2018-01-09-04:25 # ll
> > total 1863604
> > -rw------- 1 root root 66255 Jan 9 04:25 dmesg.txt
> > -rw-r--r-- 1 root root 182 Jan 9 04:25 README.txt
> > -rw-r--r-- 1 root root 2818240 Jan 9 04:25 System.map-4.15.0.gb2cd1df-master
> > -rw------- 1 root root 1832914928 Jan 9 04:25 vmcore
> > -rw-r--r-- 1 root root 72514993 Jan 9 04:25 vmlinux-4.15.0.gb2cd1df-master.gz
> >
> > Yup, all better.
> >
> > > Sorry for the mess.
> >
> > (why, developers not installing shiny new bugs is a whole lot worse:)
> >
> > > From 100fd567754f1457be94732046aefca204c842d2 Mon Sep 17 00:00:00 2001
> > > From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> > > Date: Tue, 9 Jan 2018 02:55:47 +0300
> > > Subject: [PATCH] kdump: Write a correct address of mem_section into vmcoreinfo
> > >
> > > Depending on configuration mem_section can now be an array or a pointer
> > > to an array allocated dynamically. In most cases, we can continue to refer
> > > to it as 'mem_section' regardless of what it is.
> > >
> > > But there's one exception: '&mem_section' means "address of the array" if
> > > mem_section is an array, but if mem_section is a pointer, it would mean
> > > "address of the pointer".
> > >
> > > We've stepped onto this in kdump code. VMCOREINFO_SYMBOL(mem_section)
> > > writes down address of pointer into vmcoreinfo, not array as we wanted.
> > >
> > > Let's introduce VMCOREINFO_ARRAY() that would handle the situation
> > > correctly for both cases.
> > >
> > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > > Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
> > > ---
> > > include/linux/crash_core.h | 2 ++
> > > kernel/crash_core.c | 2 +-
> > > 2 files changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
> > > index 06097ef30449..83ae04950269 100644
> > > --- a/include/linux/crash_core.h
> > > +++ b/include/linux/crash_core.h
> > > @@ -42,6 +42,8 @@ phys_addr_t paddr_vmcoreinfo_note(void);
> > > vmcoreinfo_append_str("PAGESIZE=%ld\n", value)
> > > #define VMCOREINFO_SYMBOL(name) \
> > > vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)&name)
> > > +#define VMCOREINFO_ARRAY(name) \
> > > + vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)name)
> > > #define VMCOREINFO_SIZE(name) \
> > > vmcoreinfo_append_str("SIZE(%s)=%lu\n", #name, \
> > > (unsigned long)sizeof(name))
> > > diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> > > index b3663896278e..d4122a837477 100644
> > > --- a/kernel/crash_core.c
> > > +++ b/kernel/crash_core.c
> > > @@ -410,7 +410,7 @@ static int __init crash_save_vmcoreinfo_init(void)
> > > VMCOREINFO_SYMBOL(contig_page_data);
> > > #endif
> > > #ifdef CONFIG_SPARSEMEM
> > > - VMCOREINFO_SYMBOL(mem_section);
> > > + VMCOREINFO_ARRAY(mem_section);
> > > VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
> > > VMCOREINFO_STRUCT_SIZE(mem_section);
> > > VMCOREINFO_OFFSET(mem_section, section_mem_map);
> >
> > _______________________________________________
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> >
> >
> >
>
>
>
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