[Artful SRU PATCH] kdump: write correct address of mem_section into vmcoreinfo

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[Artful SRU PATCH] kdump: write correct address of mem_section into vmcoreinfo

Thadeu Lima de Souza Cascardo-3
From: "Kirill A. Shutemov" <[hidden email]>

BugLink: http://bugs.launchpad.net/bugs/1750021

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@...
Signed-off-by: Kirill A. Shutemov <[hidden email]>
Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
Acked-by: Baoquan He <[hidden email]>
Acked-by: Dave Young <[hidden email]>
Cc: Ingo Molnar <[hidden email]>
Cc: Thomas Gleixner <[hidden email]>
Cc: "H. Peter Anvin" <[hidden email]>
Cc: Greg Kroah-Hartman <[hidden email]>
Cc: Dave Young <[hidden email]>
Cc: Baoquan He <[hidden email]>
Cc: Vivek Goyal <[hidden email]>
Cc: <[hidden email]>
Signed-off-by: Andrew Morton <[hidden email]>
Signed-off-by: Linus Torvalds <[hidden email]>
(cherry picked from commit a0b1280368d1e91ab72f849ef095b4f07a39bbf1)
Signed-off-by: Thadeu Lima de Souza Cascardo <[hidden email]>
---
 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 2df2118fbe13..b1c889225e9a 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -41,6 +41,8 @@ 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))
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 6db80fc0810b..2d90996dbe77 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -409,7 +409,7 @@ 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);
--
2.15.1


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ACK: [Artful SRU PATCH] kdump: write correct address of mem_section into vmcoreinfo

Kleber Souza
On 03/05/18 10:08, Thadeu Lima de Souza Cascardo wrote:

> From: "Kirill A. Shutemov" <[hidden email]>
>
> BugLink: http://bugs.launchpad.net/bugs/1750021
>
> 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@...
> Signed-off-by: Kirill A. Shutemov <[hidden email]>
> Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
> Acked-by: Baoquan He <[hidden email]>
> Acked-by: Dave Young <[hidden email]>
> Cc: Ingo Molnar <[hidden email]>
> Cc: Thomas Gleixner <[hidden email]>
> Cc: "H. Peter Anvin" <[hidden email]>
> Cc: Greg Kroah-Hartman <[hidden email]>
> Cc: Dave Young <[hidden email]>
> Cc: Baoquan He <[hidden email]>
> Cc: Vivek Goyal <[hidden email]>
> Cc: <[hidden email]>
> Signed-off-by: Andrew Morton <[hidden email]>
> Signed-off-by: Linus Torvalds <[hidden email]>
> (cherry picked from commit a0b1280368d1e91ab72f849ef095b4f07a39bbf1)
> Signed-off-by: Thadeu Lima de Souza Cascardo <[hidden email]>
> ---
>  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 2df2118fbe13..b1c889225e9a 100644
> --- a/include/linux/crash_core.h
> +++ b/include/linux/crash_core.h
> @@ -41,6 +41,8 @@ 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))
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 6db80fc0810b..2d90996dbe77 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -409,7 +409,7 @@ 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);
>

Clean cherry pick, tested to fix a regression.

Acked-by: Kleber Sacilotto de Souza <[hidden email]>

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ACK: [Artful SRU PATCH] kdump: write correct address of mem_section into vmcoreinfo

Marcelo Henrique Cerri
In reply to this post by Thadeu Lima de Souza Cascardo-3
Acked-by: Marcelo Henrique Cerri <[hidden email]>

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APPLIED[Artful/backlog]: [Artful SRU PATCH] kdump: write correct address of mem_section into vmcoreinfo

Kleber Souza
In reply to this post by Thadeu Lima de Souza Cascardo-3
On 03/05/18 10:08, Thadeu Lima de Souza Cascardo wrote:

> From: "Kirill A. Shutemov" <[hidden email]>
>
> BugLink: http://bugs.launchpad.net/bugs/1750021
>
> 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@...
> Signed-off-by: Kirill A. Shutemov <[hidden email]>
> Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
> Acked-by: Baoquan He <[hidden email]>
> Acked-by: Dave Young <[hidden email]>
> Cc: Ingo Molnar <[hidden email]>
> Cc: Thomas Gleixner <[hidden email]>
> Cc: "H. Peter Anvin" <[hidden email]>
> Cc: Greg Kroah-Hartman <[hidden email]>
> Cc: Dave Young <[hidden email]>
> Cc: Baoquan He <[hidden email]>
> Cc: Vivek Goyal <[hidden email]>
> Cc: <[hidden email]>
> Signed-off-by: Andrew Morton <[hidden email]>
> Signed-off-by: Linus Torvalds <[hidden email]>
> (cherry picked from commit a0b1280368d1e91ab72f849ef095b4f07a39bbf1)
> Signed-off-by: Thadeu Lima de Souza Cascardo <[hidden email]>
> ---
>  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 2df2118fbe13..b1c889225e9a 100644
> --- a/include/linux/crash_core.h
> +++ b/include/linux/crash_core.h
> @@ -41,6 +41,8 @@ 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))
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 6db80fc0810b..2d90996dbe77 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -409,7 +409,7 @@ 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);
>

Applied to artful/master-next-backlog branch.

Thanks,
Kleber

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