* [PATCH v2 1/4] mm: Create a new system state and fix core_kernel_text()
@ 2021-09-28 7:15 Christophe Leroy
2021-09-28 7:15 ` [PATCH v2 2/4] mm: Make generic arch_is_kernel_initmem_freed() do what it says Christophe Leroy
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Christophe Leroy @ 2021-09-28 7:15 UTC (permalink / raw)
To: Andrew Morton, arnd
Cc: Christophe Leroy, linux-kernel, linux-mm, linux-s390,
linuxppc-dev, linux-arch, Gerald Schaefer
core_kernel_text() considers that until system_state in at least
SYSTEM_RUNNING, init memory is valid.
But init memory is freed a few lines before setting SYSTEM_RUNNING,
so we have a small period of time when core_kernel_text() is wrong.
Create an intermediate system state called SYSTEM_FREEING_INIT that
is set before starting freeing init memory, and use it in
core_kernel_text() to report init memory invalid earlier.
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: New
---
include/linux/kernel.h | 1 +
init/main.c | 2 ++
kernel/extable.c | 2 +-
3 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 2776423a587e..471bc0593679 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -248,6 +248,7 @@ extern bool early_boot_irqs_disabled;
extern enum system_states {
SYSTEM_BOOTING,
SYSTEM_SCHEDULING,
+ SYSTEM_FREEING_INITMEM,
SYSTEM_RUNNING,
SYSTEM_HALT,
SYSTEM_POWER_OFF,
diff --git a/init/main.c b/init/main.c
index 3f7216934441..c457d393fdd4 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1505,6 +1505,8 @@ static int __ref kernel_init(void *unused)
kernel_init_freeable();
/* need to finish all async __init code before freeing the memory */
async_synchronize_full();
+
+ system_state = SYSTEM_FREEING_INITMEM;
kprobe_free_init_mem();
ftrace_free_init_mem();
kgdb_free_init_mem();
diff --git a/kernel/extable.c b/kernel/extable.c
index b0ea5eb0c3b4..290661f68e6b 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -76,7 +76,7 @@ int notrace core_kernel_text(unsigned long addr)
addr < (unsigned long)_etext)
return 1;
- if (system_state < SYSTEM_RUNNING &&
+ if (system_state < SYSTEM_FREEING_INITMEM &&
init_kernel_text(addr))
return 1;
return 0;
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 2/4] mm: Make generic arch_is_kernel_initmem_freed() do what it says
2021-09-28 7:15 [PATCH v2 1/4] mm: Create a new system state and fix core_kernel_text() Christophe Leroy
@ 2021-09-28 7:15 ` Christophe Leroy
2021-09-29 3:30 ` Andrew Morton
2021-09-28 7:15 ` [PATCH v2 3/4] powerpc: Use generic version of arch_is_kernel_initmem_freed() Christophe Leroy
2021-09-28 7:15 ` [PATCH v2 4/4] s390: " Christophe Leroy
2 siblings, 1 reply; 6+ messages in thread
From: Christophe Leroy @ 2021-09-28 7:15 UTC (permalink / raw)
To: Andrew Morton, arnd
Cc: Christophe Leroy, linux-kernel, linux-mm, linux-s390,
linuxppc-dev, linux-arch, Gerald Schaefer
Commit 7a5da02de8d6 ("locking/lockdep: check for freed initmem in
static_obj()") added arch_is_kernel_initmem_freed() which is supposed
to report whether an object is part of already freed init memory.
For the time being, the generic version of arch_is_kernel_initmem_freed()
always reports 'false', allthough free_initmem() is generically called
on all architectures.
Therefore, change the generic version of arch_is_kernel_initmem_freed()
to check whether free_initmem() has been called. If so, then check
if a given address falls into init memory.
In order to use function init_section_contains(), the fonction is
moved at the end of asm-generic/section.h
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: Change to using the new SYSTEM_FREEING_INITMEM state
---
include/asm-generic/sections.h | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index d16302d3eb59..13f301239007 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -80,20 +80,6 @@ static inline int arch_is_kernel_data(unsigned long addr)
}
#endif
-/*
- * Check if an address is part of freed initmem. This is needed on architectures
- * with virt == phys kernel mapping, for code that wants to check if an address
- * is part of a static object within [_stext, _end]. After initmem is freed,
- * memory can be allocated from it, and such allocations would then have
- * addresses within the range [_stext, _end].
- */
-#ifndef arch_is_kernel_initmem_freed
-static inline int arch_is_kernel_initmem_freed(unsigned long addr)
-{
- return 0;
-}
-#endif
-
/**
* memory_contains - checks if an object is contained within a memory region
* @begin: virtual address of the beginning of the memory region
@@ -172,4 +158,21 @@ static inline bool is_kernel_rodata(unsigned long addr)
addr < (unsigned long)__end_rodata;
}
+/*
+ * Check if an address is part of freed initmem. This is needed on architectures
+ * with virt == phys kernel mapping, for code that wants to check if an address
+ * is part of a static object within [_stext, _end]. After initmem is freed,
+ * memory can be allocated from it, and such allocations would then have
+ * addresses within the range [_stext, _end].
+ */
+#ifndef arch_is_kernel_initmem_freed
+static inline int arch_is_kernel_initmem_freed(unsigned long addr)
+{
+ if (system_state < SYSTEM_FREEING_INITMEM)
+ return 0;
+
+ return init_section_contains((void *)addr, 1);
+}
+#endif
+
#endif /* _ASM_GENERIC_SECTIONS_H_ */
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2 2/4] mm: Make generic arch_is_kernel_initmem_freed() do what it says
2021-09-28 7:15 ` [PATCH v2 2/4] mm: Make generic arch_is_kernel_initmem_freed() do what it says Christophe Leroy
@ 2021-09-29 3:30 ` Andrew Morton
0 siblings, 0 replies; 6+ messages in thread
From: Andrew Morton @ 2021-09-29 3:30 UTC (permalink / raw)
To: Christophe Leroy
Cc: arnd, linux-kernel, linux-mm, linux-s390, linuxppc-dev,
linux-arch, Gerald Schaefer, Stephen Rothwell
On Tue, 28 Sep 2021 09:15:35 +0200 Christophe Leroy <christophe.leroy@csgroup.eu> wrote:
> Commit 7a5da02de8d6 ("locking/lockdep: check for freed initmem in
> static_obj()") added arch_is_kernel_initmem_freed() which is supposed
> to report whether an object is part of already freed init memory.
>
> For the time being, the generic version of arch_is_kernel_initmem_freed()
> always reports 'false', allthough free_initmem() is generically called
> on all architectures.
>
> Therefore, change the generic version of arch_is_kernel_initmem_freed()
> to check whether free_initmem() has been called. If so, then check
> if a given address falls into init memory.
>
> In order to use function init_section_contains(), the fonction is
> moved at the end of asm-generic/section.h
i386 allmodconfig:
In file included from arch/x86/platform/intel-quark/imr.c:28:
./include/asm-generic/sections.h: In function 'arch_is_kernel_initmem_freed':
./include/asm-generic/sections.h:171:6: error: 'system_state' undeclared (first use in this function)
171 | if (system_state < SYSTEM_FREEING_INITMEM)
| ^~~~~~~~~~~~
./include/asm-generic/sections.h:171:6: note: each undeclared identifier is reported only once for each function it appears in
./include/asm-generic/sections.h:171:21: error: 'SYSTEM_FREEING_INITMEM' undeclared (first use in this function)
171 | if (system_state < SYSTEM_FREEING_INITMEM)
| ^~~~~~~~~~~~~~~~~~~~~~
I don't think it would be a good idea to include kernel.h from
sections.h - it's unclear to me which is the "innermost" of those two.
It would be better to uninline arch_is_kernel_initmem_freed(). Surely
there's no real reason for inlining it?
Anyway, I'll drop the series for now.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2 3/4] powerpc: Use generic version of arch_is_kernel_initmem_freed()
2021-09-28 7:15 [PATCH v2 1/4] mm: Create a new system state and fix core_kernel_text() Christophe Leroy
2021-09-28 7:15 ` [PATCH v2 2/4] mm: Make generic arch_is_kernel_initmem_freed() do what it says Christophe Leroy
@ 2021-09-28 7:15 ` Christophe Leroy
2021-09-28 7:15 ` [PATCH v2 4/4] s390: " Christophe Leroy
2 siblings, 0 replies; 6+ messages in thread
From: Christophe Leroy @ 2021-09-28 7:15 UTC (permalink / raw)
To: Andrew Morton, arnd
Cc: Christophe Leroy, linux-kernel, linux-mm, linux-s390,
linuxppc-dev, linux-arch
Generic version of arch_is_kernel_initmem_freed() now does the same
as powerpc version.
Remove the powerpc version.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: No change
---
arch/powerpc/include/asm/sections.h | 13 -------------
1 file changed, 13 deletions(-)
diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
index 6e4af4492a14..79cb7a25a5fb 100644
--- a/arch/powerpc/include/asm/sections.h
+++ b/arch/powerpc/include/asm/sections.h
@@ -6,21 +6,8 @@
#include <linux/elf.h>
#include <linux/uaccess.h>
-#define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed
-
#include <asm-generic/sections.h>
-extern bool init_mem_is_free;
-
-static inline int arch_is_kernel_initmem_freed(unsigned long addr)
-{
- if (!init_mem_is_free)
- return 0;
-
- return addr >= (unsigned long)__init_begin &&
- addr < (unsigned long)__init_end;
-}
-
extern char __head_end[];
#ifdef __powerpc64__
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 4/4] s390: Use generic version of arch_is_kernel_initmem_freed()
2021-09-28 7:15 [PATCH v2 1/4] mm: Create a new system state and fix core_kernel_text() Christophe Leroy
2021-09-28 7:15 ` [PATCH v2 2/4] mm: Make generic arch_is_kernel_initmem_freed() do what it says Christophe Leroy
2021-09-28 7:15 ` [PATCH v2 3/4] powerpc: Use generic version of arch_is_kernel_initmem_freed() Christophe Leroy
@ 2021-09-28 7:15 ` Christophe Leroy
2021-09-28 9:45 ` Heiko Carstens
2 siblings, 1 reply; 6+ messages in thread
From: Christophe Leroy @ 2021-09-28 7:15 UTC (permalink / raw)
To: Andrew Morton, arnd
Cc: Christophe Leroy, linux-kernel, linux-mm, linux-s390,
linuxppc-dev, linux-arch, Gerald Schaefer
Generic version of arch_is_kernel_initmem_freed() now does the same
as s390 version.
Remove the s390 version.
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: No change
---
arch/s390/include/asm/sections.h | 12 ------------
arch/s390/mm/init.c | 3 ---
2 files changed, 15 deletions(-)
diff --git a/arch/s390/include/asm/sections.h b/arch/s390/include/asm/sections.h
index 85881dd48022..3fecaa4e8b74 100644
--- a/arch/s390/include/asm/sections.h
+++ b/arch/s390/include/asm/sections.h
@@ -2,20 +2,8 @@
#ifndef _S390_SECTIONS_H
#define _S390_SECTIONS_H
-#define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed
-
#include <asm-generic/sections.h>
-extern bool initmem_freed;
-
-static inline int arch_is_kernel_initmem_freed(unsigned long addr)
-{
- if (!initmem_freed)
- return 0;
- return addr >= (unsigned long)__init_begin &&
- addr < (unsigned long)__init_end;
-}
-
/*
* .boot.data section contains variables "shared" between the decompressor and
* the decompressed kernel. The decompressor will store values in them, and
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index a04faf49001a..8c6f258a6183 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -58,8 +58,6 @@ unsigned long empty_zero_page, zero_page_mask;
EXPORT_SYMBOL(empty_zero_page);
EXPORT_SYMBOL(zero_page_mask);
-bool initmem_freed;
-
static void __init setup_zero_pages(void)
{
unsigned int order;
@@ -214,7 +212,6 @@ void __init mem_init(void)
void free_initmem(void)
{
- initmem_freed = true;
__set_memory((unsigned long)_sinittext,
(unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT,
SET_MEMORY_RW | SET_MEMORY_NX);
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2 4/4] s390: Use generic version of arch_is_kernel_initmem_freed()
2021-09-28 7:15 ` [PATCH v2 4/4] s390: " Christophe Leroy
@ 2021-09-28 9:45 ` Heiko Carstens
0 siblings, 0 replies; 6+ messages in thread
From: Heiko Carstens @ 2021-09-28 9:45 UTC (permalink / raw)
To: Christophe Leroy
Cc: Andrew Morton, arnd, linux-kernel, linux-mm, linux-s390,
linuxppc-dev, linux-arch, Gerald Schaefer
On Tue, Sep 28, 2021 at 09:15:37AM +0200, Christophe Leroy wrote:
> Generic version of arch_is_kernel_initmem_freed() now does the same
> as s390 version.
>
> Remove the s390 version.
>
> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
> v2: No change
> ---
> arch/s390/include/asm/sections.h | 12 ------------
> arch/s390/mm/init.c | 3 ---
> 2 files changed, 15 deletions(-)
Looks good. Thanks for cleaning this up!
Acked-by: Heiko Carstens <hca@linux.ibm.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-09-29 3:30 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-28 7:15 [PATCH v2 1/4] mm: Create a new system state and fix core_kernel_text() Christophe Leroy
2021-09-28 7:15 ` [PATCH v2 2/4] mm: Make generic arch_is_kernel_initmem_freed() do what it says Christophe Leroy
2021-09-29 3:30 ` Andrew Morton
2021-09-28 7:15 ` [PATCH v2 3/4] powerpc: Use generic version of arch_is_kernel_initmem_freed() Christophe Leroy
2021-09-28 7:15 ` [PATCH v2 4/4] s390: " Christophe Leroy
2021-09-28 9:45 ` Heiko Carstens
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).