* [PATCH] kdump: Write a correct address of mem_section into vmcoreinfo
@ 2018-01-12 16:25 Kirill A. Shutemov
2018-01-13 10:48 ` Ingo Molnar
2018-01-13 10:52 ` [tip:x86/urgent] kdump: Write the " tip-bot for Kirill A. Shutemov
0 siblings, 2 replies; 4+ messages in thread
From: Kirill A. Shutemov @ 2018-01-12 16:25 UTC (permalink / raw)
To: Ingo Molnar, Andrew Morton, x86, Thomas Gleixner, H. Peter Anvin
Cc: linux-mm, linux-kernel, Greg Kroah-Hartman, Dave Young,
Baoquan He, Vivek Goyal, kexec, Kirill A. Shutemov, stable
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.
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")
Cc: stable@vger.kernel.org
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
---
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..b511f6d24b42 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_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 b3663896278e..4f63597c824d 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_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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] kdump: Write a correct address of mem_section into vmcoreinfo
2018-01-12 16:25 [PATCH] kdump: Write a correct address of mem_section into vmcoreinfo Kirill A. Shutemov
@ 2018-01-13 10:48 ` Ingo Molnar
2018-01-13 18:26 ` Kirill A. Shutemov
2018-01-13 10:52 ` [tip:x86/urgent] kdump: Write the " tip-bot for Kirill A. Shutemov
1 sibling, 1 reply; 4+ messages in thread
From: Ingo Molnar @ 2018-01-13 10:48 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: Ingo Molnar, Andrew Morton, x86, Thomas Gleixner, H. Peter Anvin,
linux-mm, linux-kernel, Greg Kroah-Hartman, Dave Young,
Baoquan He, Vivek Goyal, kexec, stable
* Kirill A. Shutemov <kirill.shutemov@linux.intel.com> wrote:
> 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.
>
> 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")
> Cc: stable@vger.kernel.org
> Acked-by: Baoquan He <bhe@redhat.com>
> Acked-by: Dave Young <dyoung@redhat.com>
You forgot the Reported-by - I added that to the commit.
Thanks,
Ingo
^ permalink raw reply [flat|nested] 4+ messages in thread
* [tip:x86/urgent] kdump: Write the correct address of mem_section into vmcoreinfo
2018-01-12 16:25 [PATCH] kdump: Write a correct address of mem_section into vmcoreinfo Kirill A. Shutemov
2018-01-13 10:48 ` Ingo Molnar
@ 2018-01-13 10:52 ` tip-bot for Kirill A. Shutemov
1 sibling, 0 replies; 4+ messages in thread
From: tip-bot for Kirill A. Shutemov @ 2018-01-13 10:52 UTC (permalink / raw)
To: linux-tip-commits
Cc: akpm, linux-kernel, bhe, vgoyal, hpa, torvalds, gregkh, peterz,
dyoung, mingo, kirill.shutemov, tglx
Commit-ID: 9f15b9120f562ae0bf0a836c96f4dafb33ae426a
Gitweb: https://git.kernel.org/tip/9f15b9120f562ae0bf0a836c96f4dafb33ae426a
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
AuthorDate: Fri, 12 Jan 2018 19:25:32 +0300
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Sat, 13 Jan 2018 11:48:06 +0100
kdump: Write the 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 the kdump code: VMCOREINFO_SYMBOL(mem_section)
writes down the address of pointer into vmcoreinfo, not the array as we wanted,
breaking kdump.
Let's introduce VMCOREINFO_SYMBOL_ARRAY() that would handle the
situation correctly for both cases.
Mike Galbraith <efault@gmx.de>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: kexec@lists.infradead.org
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org
Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
Link: http://lkml.kernel.org/r/20180112162532.35896-1-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
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 06097ef..b511f6d 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_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 b366389..4f63597 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_SYMBOL_ARRAY(mem_section);
VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
VMCOREINFO_STRUCT_SIZE(mem_section);
VMCOREINFO_OFFSET(mem_section, section_mem_map);
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] kdump: Write a correct address of mem_section into vmcoreinfo
2018-01-13 10:48 ` Ingo Molnar
@ 2018-01-13 18:26 ` Kirill A. Shutemov
0 siblings, 0 replies; 4+ messages in thread
From: Kirill A. Shutemov @ 2018-01-13 18:26 UTC (permalink / raw)
To: Ingo Molnar
Cc: Kirill A. Shutemov, Ingo Molnar, Andrew Morton, x86,
Thomas Gleixner, H. Peter Anvin, linux-mm, linux-kernel,
Greg Kroah-Hartman, Dave Young, Baoquan He, Vivek Goyal, kexec,
stable
On Sat, Jan 13, 2018 at 11:48:38AM +0100, Ingo Molnar wrote:
>
> * Kirill A. Shutemov <kirill.shutemov@linux.intel.com> wrote:
>
> > 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.
> >
> > 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")
> > Cc: stable@vger.kernel.org
> > Acked-by: Baoquan He <bhe@redhat.com>
> > Acked-by: Dave Young <dyoung@redhat.com>
>
> You forgot the Reported-by - I added that to the commit.
Oops, sorry.
Note, that Andrew has already pick it up and sent it upstream.
--
Kirill A. Shutemov
^ permalink raw reply [flat|nested] 4+ messages in thread
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