Hi Kirill,
I setup qemu 2.9.0 to test 5-level on kexec/kdump support. While both kexec and kdump reset to BIOS immediately after triggering. I saw your patch adding 5-level paging support for kexec. Wonder if your test succeeded to jump into kexec/kdump kernel, and what else I need to make it. By the way, I just tested the latest upstream kernel.
commit 7f6890418 x86/kexec: Add 5-level paging support
[ ~]$ qemu-system-x86_64 --version QEMU emulator version 2.9.0(qemu-2.9.0-1.fc26.1) Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers
Thanks Baoquan
On 01/09/18 at 03:13am, Kirill A. Shutemov wrote:
On Mon, Jan 08, 2018 at 08:46:53PM +0300, Kirill A. Shutemov wrote:
On Mon, Jan 08, 2018 at 04:04:44PM +0000, Ingo Molnar wrote:
hi Kirill,
As Mike reported it below, your 5-level paging related upstream commit 83e3c48729d9 and all its followup fixes:
83e3c48729d9: mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y 629a359bdb0e: mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=y d09cfbbfa0f7: mm/sparse.c: wrong allocation for mem_section
... still breaks kexec - and that now regresses -stable as well.
Given that 5-level paging now syntactically depends on having this commit, if we fully revert this then we'll have to disable 5-level paging as well.
This *should* help.
Mike, could you test this? (On top of the rest of the fixes.)
Sorry for the mess.
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);
-- Kirill A. Shutemov
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