Commit a0b12803 authored Jan 12, 2018 by Kirill A. Shutemov Committed by Linus Torvalds Jan 13, 2018

kdump: write 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_SYMBOL_ARRAY() that would handle the
situation correctly for both cases.

Link: http://lkml.kernel.org/r/20180112162532.35896-1-kirill.shutemov@linux.intel.com


Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: 83e3c487 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent d9570ee3

include/linux/crash_core.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -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_SYMBOL_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))

kernel/crash_core.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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_SYMBOL_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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