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* [PATCH] module: Fix link failure due to invalid relocation on namespace offset
@ 2019-09-11 12:26 Will Deacon
  2019-09-11 13:35 ` Jessica Yu
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Will Deacon @ 2019-09-11 12:26 UTC (permalink / raw)
  To: linux-kernel
  Cc: maco, gregkh, Will Deacon, Matthias Maennich, Jessica Yu,
	Ard Biesheuvel, Catalin Marinas

Commit 8651ec01daed ("module: add support for symbol namespaces.")
broke linking for arm64 defconfig:

  | lib/crypto/arc4.o: In function `__ksymtab_arc4_setkey':
  | arc4.c:(___ksymtab+arc4_setkey+0x8): undefined reference to `no symbol'
  | lib/crypto/arc4.o: In function `__ksymtab_arc4_crypt':
  | arc4.c:(___ksymtab+arc4_crypt+0x8): undefined reference to `no symbol'

This is because the dummy initialisation of the 'namespace_offset' field
in 'struct kernel_symbol' when using EXPORT_SYMBOL on architectures with
support for PREL32 locations uses an offset from an absolute address (0)
in an effort to trick 'offset_to_pointer' into behaving as a NOP,
allowing non-namespaced symbols to be treated in the same way as those
belonging to a namespace.

Unfortunately, place-relative relocations require a symbol reference
rather than an absolute value and, although x86 appears to get away with
this due to placing the kernel text at the top of the address space, it
almost certainly results in a runtime failure if the kernel is relocated
dynamically as a result of KASLR.

Rework 'namespace_offset' so that a value of 0, which cannot occur for a
valid namespaced symbol, indicates that the corresponding symbol does
not belong to a namespace.

Cc: Matthias Maennich <maennich@google.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Fixes: 8651ec01daed ("module: add support for symbol namespaces.")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Will Deacon <will@kernel.org>
---

Please note that I've not been able to test this at LPC, but it's been
submitted to kernelci.

 include/asm-generic/export.h | 2 +-
 include/linux/export.h       | 2 +-
 kernel/module.c              | 2 ++
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
index e2b5d0f569d3..d0912c7ac2fc 100644
--- a/include/asm-generic/export.h
+++ b/include/asm-generic/export.h
@@ -17,7 +17,7 @@
 
 .macro __put, val, name
 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
-	.long	\val - ., \name - ., 0 - .
+	.long	\val - ., \name - ., 0
 #elif defined(CONFIG_64BIT)
 	.quad	\val, \name, 0
 #else
diff --git a/include/linux/export.h b/include/linux/export.h
index 2c5468d8ea9a..ef5d015d754a 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -68,7 +68,7 @@ extern struct module __this_module;
 	    "__ksymtab_" #sym ":				\n"	\
 	    "	.long	" #sym "- .				\n"	\
 	    "	.long	__kstrtab_" #sym "- .			\n"	\
-	    "	.long	0 - .					\n"	\
+	    "	.long	0					\n"	\
 	    "	.previous					\n")
 
 struct kernel_symbol {
diff --git a/kernel/module.c b/kernel/module.c
index f76efcf2043e..7ab244c4e1ba 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -547,6 +547,8 @@ static const char *kernel_symbol_name(const struct kernel_symbol *sym)
 static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
 {
 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+	if (!sym->namespace_offset)
+		return NULL;
 	return offset_to_ptr(&sym->namespace_offset);
 #else
 	return sym->namespace;
-- 
2.23.0.162.g0b9fbb3734-goog


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] module: Fix link failure due to invalid relocation on namespace offset
  2019-09-11 12:26 [PATCH] module: Fix link failure due to invalid relocation on namespace offset Will Deacon
@ 2019-09-11 13:35 ` Jessica Yu
  2019-09-11 16:40   ` Will Deacon
  2019-09-11 16:51 ` Ard Biesheuvel
  2019-09-11 18:26 ` Jessica Yu
  2 siblings, 1 reply; 6+ messages in thread
From: Jessica Yu @ 2019-09-11 13:35 UTC (permalink / raw)
  To: Will Deacon
  Cc: linux-kernel, maco, gregkh, Matthias Maennich, Ard Biesheuvel,
	Catalin Marinas

+++ Will Deacon [11/09/19 13:26 +0100]:
>Commit 8651ec01daed ("module: add support for symbol namespaces.")
>broke linking for arm64 defconfig:
>
>  | lib/crypto/arc4.o: In function `__ksymtab_arc4_setkey':
>  | arc4.c:(___ksymtab+arc4_setkey+0x8): undefined reference to `no symbol'
>  | lib/crypto/arc4.o: In function `__ksymtab_arc4_crypt':
>  | arc4.c:(___ksymtab+arc4_crypt+0x8): undefined reference to `no symbol'
>
>This is because the dummy initialisation of the 'namespace_offset' field
>in 'struct kernel_symbol' when using EXPORT_SYMBOL on architectures with
>support for PREL32 locations uses an offset from an absolute address (0)
>in an effort to trick 'offset_to_pointer' into behaving as a NOP,
>allowing non-namespaced symbols to be treated in the same way as those
>belonging to a namespace.
>
>Unfortunately, place-relative relocations require a symbol reference
>rather than an absolute value and, although x86 appears to get away with
>this due to placing the kernel text at the top of the address space, it
>almost certainly results in a runtime failure if the kernel is relocated
>dynamically as a result of KASLR.
>
>Rework 'namespace_offset' so that a value of 0, which cannot occur for a
>valid namespaced symbol, indicates that the corresponding symbol does
>not belong to a namespace.
>
>Cc: Matthias Maennich <maennich@google.com>
>Cc: Jessica Yu <jeyu@kernel.org>
>Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>Cc: Catalin Marinas <catalin.marinas@arm.com>
>Fixes: 8651ec01daed ("module: add support for symbol namespaces.")
>Reported-by: kbuild test robot <lkp@intel.com>
>Signed-off-by: Will Deacon <will@kernel.org>
>---
>
>Please note that I've not been able to test this at LPC, but it's been
>submitted to kernelci.

Thanks for fixing this so quickly. I can confirm that this fixes the
build for arm64 defconfig and x86 built fine for me as well. I'll wait
a bit and apply this at the end of the day in case Matthias or anybody
else would like to confirm/test.

Thanks,

Jessica

> include/asm-generic/export.h | 2 +-
> include/linux/export.h       | 2 +-
> kernel/module.c              | 2 ++
> 3 files changed, 4 insertions(+), 2 deletions(-)
>
>diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
>index e2b5d0f569d3..d0912c7ac2fc 100644
>--- a/include/asm-generic/export.h
>+++ b/include/asm-generic/export.h
>@@ -17,7 +17,7 @@
>
> .macro __put, val, name
> #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
>-	.long	\val - ., \name - ., 0 - .
>+	.long	\val - ., \name - ., 0
> #elif defined(CONFIG_64BIT)
> 	.quad	\val, \name, 0
> #else
>diff --git a/include/linux/export.h b/include/linux/export.h
>index 2c5468d8ea9a..ef5d015d754a 100644
>--- a/include/linux/export.h
>+++ b/include/linux/export.h
>@@ -68,7 +68,7 @@ extern struct module __this_module;
> 	    "__ksymtab_" #sym ":				\n"	\
> 	    "	.long	" #sym "- .				\n"	\
> 	    "	.long	__kstrtab_" #sym "- .			\n"	\
>-	    "	.long	0 - .					\n"	\
>+	    "	.long	0					\n"	\
> 	    "	.previous					\n")
>
> struct kernel_symbol {
>diff --git a/kernel/module.c b/kernel/module.c
>index f76efcf2043e..7ab244c4e1ba 100644
>--- a/kernel/module.c
>+++ b/kernel/module.c
>@@ -547,6 +547,8 @@ static const char *kernel_symbol_name(const struct kernel_symbol *sym)
> static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
> {
> #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
>+	if (!sym->namespace_offset)
>+		return NULL;
> 	return offset_to_ptr(&sym->namespace_offset);
> #else
> 	return sym->namespace;
>-- 
>2.23.0.162.g0b9fbb3734-goog
>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] module: Fix link failure due to invalid relocation on namespace offset
  2019-09-11 13:35 ` Jessica Yu
@ 2019-09-11 16:40   ` Will Deacon
  2019-09-11 16:53     ` Matthias Maennich
  0 siblings, 1 reply; 6+ messages in thread
From: Will Deacon @ 2019-09-11 16:40 UTC (permalink / raw)
  To: Jessica Yu
  Cc: linux-kernel, maco, gregkh, Matthias Maennich, Ard Biesheuvel,
	Catalin Marinas

On Wed, Sep 11, 2019 at 03:35:06PM +0200, Jessica Yu wrote:
> +++ Will Deacon [11/09/19 13:26 +0100]:
> > Commit 8651ec01daed ("module: add support for symbol namespaces.")
> > broke linking for arm64 defconfig:
> > 
> >  | lib/crypto/arc4.o: In function `__ksymtab_arc4_setkey':
> >  | arc4.c:(___ksymtab+arc4_setkey+0x8): undefined reference to `no symbol'
> >  | lib/crypto/arc4.o: In function `__ksymtab_arc4_crypt':
> >  | arc4.c:(___ksymtab+arc4_crypt+0x8): undefined reference to `no symbol'
> > 
> > This is because the dummy initialisation of the 'namespace_offset' field
> > in 'struct kernel_symbol' when using EXPORT_SYMBOL on architectures with
> > support for PREL32 locations uses an offset from an absolute address (0)
> > in an effort to trick 'offset_to_pointer' into behaving as a NOP,
> > allowing non-namespaced symbols to be treated in the same way as those
> > belonging to a namespace.
> > 
> > Unfortunately, place-relative relocations require a symbol reference
> > rather than an absolute value and, although x86 appears to get away with
> > this due to placing the kernel text at the top of the address space, it
> > almost certainly results in a runtime failure if the kernel is relocated
> > dynamically as a result of KASLR.
> > 
> > Rework 'namespace_offset' so that a value of 0, which cannot occur for a
> > valid namespaced symbol, indicates that the corresponding symbol does
> > not belong to a namespace.
> > 
> > Cc: Matthias Maennich <maennich@google.com>
> > Cc: Jessica Yu <jeyu@kernel.org>
> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > Fixes: 8651ec01daed ("module: add support for symbol namespaces.")
> > Reported-by: kbuild test robot <lkp@intel.com>
> > Signed-off-by: Will Deacon <will@kernel.org>
> > ---
> > 
> > Please note that I've not been able to test this at LPC, but it's been
> > submitted to kernelci.
> 
> Thanks for fixing this so quickly. I can confirm that this fixes the
> build for arm64 defconfig and x86 built fine for me as well. I'll wait
> a bit and apply this at the end of the day in case Matthias or anybody
> else would like to confirm/test.

FWIW, I've managed to boot arm64 Debian under QEMU and load/unload
modules successfully with this patch applied on top of modules-next.

Will

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] module: Fix link failure due to invalid relocation on namespace offset
  2019-09-11 12:26 [PATCH] module: Fix link failure due to invalid relocation on namespace offset Will Deacon
  2019-09-11 13:35 ` Jessica Yu
@ 2019-09-11 16:51 ` Ard Biesheuvel
  2019-09-11 18:26 ` Jessica Yu
  2 siblings, 0 replies; 6+ messages in thread
From: Ard Biesheuvel @ 2019-09-11 16:51 UTC (permalink / raw)
  To: Will Deacon
  Cc: Linux Kernel Mailing List, Martijn Coenen, Greg Kroah-Hartman,
	Matthias Maennich, Jessica Yu, Catalin Marinas

On Wed, 11 Sep 2019 at 13:26, Will Deacon <will@kernel.org> wrote:
>
> Commit 8651ec01daed ("module: add support for symbol namespaces.")
> broke linking for arm64 defconfig:
>
>   | lib/crypto/arc4.o: In function `__ksymtab_arc4_setkey':
>   | arc4.c:(___ksymtab+arc4_setkey+0x8): undefined reference to `no symbol'
>   | lib/crypto/arc4.o: In function `__ksymtab_arc4_crypt':
>   | arc4.c:(___ksymtab+arc4_crypt+0x8): undefined reference to `no symbol'
>
> This is because the dummy initialisation of the 'namespace_offset' field
> in 'struct kernel_symbol' when using EXPORT_SYMBOL on architectures with
> support for PREL32 locations uses an offset from an absolute address (0)
> in an effort to trick 'offset_to_pointer' into behaving as a NOP,
> allowing non-namespaced symbols to be treated in the same way as those
> belonging to a namespace.
>
> Unfortunately, place-relative relocations require a symbol reference
> rather than an absolute value and, although x86 appears to get away with
> this due to placing the kernel text at the top of the address space, it
> almost certainly results in a runtime failure if the kernel is relocated
> dynamically as a result of KASLR.
>
> Rework 'namespace_offset' so that a value of 0, which cannot occur for a
> valid namespaced symbol, indicates that the corresponding symbol does
> not belong to a namespace.
>
> Cc: Matthias Maennich <maennich@google.com>
> Cc: Jessica Yu <jeyu@kernel.org>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Fixes: 8651ec01daed ("module: add support for symbol namespaces.")
> Reported-by: kbuild test robot <lkp@intel.com>
> Signed-off-by: Will Deacon <will@kernel.org>
> ---
>
> Please note that I've not been able to test this at LPC, but it's been
> submitted to kernelci.
>

The build tests all passed, and the boot tests that have completed by
now all look fine, so

Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

>  include/asm-generic/export.h | 2 +-
>  include/linux/export.h       | 2 +-
>  kernel/module.c              | 2 ++
>  3 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
> index e2b5d0f569d3..d0912c7ac2fc 100644
> --- a/include/asm-generic/export.h
> +++ b/include/asm-generic/export.h
> @@ -17,7 +17,7 @@
>
>  .macro __put, val, name
>  #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
> -       .long   \val - ., \name - ., 0 - .
> +       .long   \val - ., \name - ., 0
>  #elif defined(CONFIG_64BIT)
>         .quad   \val, \name, 0
>  #else
> diff --git a/include/linux/export.h b/include/linux/export.h
> index 2c5468d8ea9a..ef5d015d754a 100644
> --- a/include/linux/export.h
> +++ b/include/linux/export.h
> @@ -68,7 +68,7 @@ extern struct module __this_module;
>             "__ksymtab_" #sym ":                                \n"     \
>             "   .long   " #sym "- .                             \n"     \
>             "   .long   __kstrtab_" #sym "- .                   \n"     \
> -           "   .long   0 - .                                   \n"     \
> +           "   .long   0                                       \n"     \
>             "   .previous                                       \n")
>
>  struct kernel_symbol {
> diff --git a/kernel/module.c b/kernel/module.c
> index f76efcf2043e..7ab244c4e1ba 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -547,6 +547,8 @@ static const char *kernel_symbol_name(const struct kernel_symbol *sym)
>  static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
>  {
>  #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
> +       if (!sym->namespace_offset)
> +               return NULL;
>         return offset_to_ptr(&sym->namespace_offset);
>  #else
>         return sym->namespace;
> --
> 2.23.0.162.g0b9fbb3734-goog
>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] module: Fix link failure due to invalid relocation on namespace offset
  2019-09-11 16:40   ` Will Deacon
@ 2019-09-11 16:53     ` Matthias Maennich
  0 siblings, 0 replies; 6+ messages in thread
From: Matthias Maennich @ 2019-09-11 16:53 UTC (permalink / raw)
  To: Will Deacon
  Cc: Jessica Yu, linux-kernel, maco, gregkh, Ard Biesheuvel,
	Catalin Marinas, kernel-team

On Wed, Sep 11, 2019 at 05:40:13PM +0100, Will Deacon wrote:
>On Wed, Sep 11, 2019 at 03:35:06PM +0200, Jessica Yu wrote:
>> +++ Will Deacon [11/09/19 13:26 +0100]:
>> > Commit 8651ec01daed ("module: add support for symbol namespaces.")
>> > broke linking for arm64 defconfig:
>> >
>> >  | lib/crypto/arc4.o: In function `__ksymtab_arc4_setkey':
>> >  | arc4.c:(___ksymtab+arc4_setkey+0x8): undefined reference to `no symbol'
>> >  | lib/crypto/arc4.o: In function `__ksymtab_arc4_crypt':
>> >  | arc4.c:(___ksymtab+arc4_crypt+0x8): undefined reference to `no symbol'
>> >
>> > This is because the dummy initialisation of the 'namespace_offset' field
>> > in 'struct kernel_symbol' when using EXPORT_SYMBOL on architectures with
>> > support for PREL32 locations uses an offset from an absolute address (0)
>> > in an effort to trick 'offset_to_pointer' into behaving as a NOP,
>> > allowing non-namespaced symbols to be treated in the same way as those
>> > belonging to a namespace.
>> >
>> > Unfortunately, place-relative relocations require a symbol reference
>> > rather than an absolute value and, although x86 appears to get away with
>> > this due to placing the kernel text at the top of the address space, it
>> > almost certainly results in a runtime failure if the kernel is relocated
>> > dynamically as a result of KASLR.
>> >
>> > Rework 'namespace_offset' so that a value of 0, which cannot occur for a
>> > valid namespaced symbol, indicates that the corresponding symbol does
>> > not belong to a namespace.
>> >
>> > Cc: Matthias Maennich <maennich@google.com>
>> > Cc: Jessica Yu <jeyu@kernel.org>
>> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> > Cc: Catalin Marinas <catalin.marinas@arm.com>
>> > Fixes: 8651ec01daed ("module: add support for symbol namespaces.")
>> > Reported-by: kbuild test robot <lkp@intel.com>
>> > Signed-off-by: Will Deacon <will@kernel.org>
>> > ---
>> >
>> > Please note that I've not been able to test this at LPC, but it's been
>> > submitted to kernelci.
>>
>> Thanks for fixing this so quickly. I can confirm that this fixes the
>> build for arm64 defconfig and x86 built fine for me as well. I'll wait
>> a bit and apply this at the end of the day in case Matthias or anybody
>> else would like to confirm/test.
>
>FWIW, I've managed to boot arm64 Debian under QEMU and load/unload
>modules successfully with this patch applied on top of modules-next.

Thanks Will for fixing this so quickly! The patch looks good to me.

Feel free to add
Reviewed-by: Matthias Maennich <maennich@google.com>
Tested-by: Matthias Maennich <maennich@google.com>

Cheers,
Matthias

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] module: Fix link failure due to invalid relocation on namespace offset
  2019-09-11 12:26 [PATCH] module: Fix link failure due to invalid relocation on namespace offset Will Deacon
  2019-09-11 13:35 ` Jessica Yu
  2019-09-11 16:51 ` Ard Biesheuvel
@ 2019-09-11 18:26 ` Jessica Yu
  2 siblings, 0 replies; 6+ messages in thread
From: Jessica Yu @ 2019-09-11 18:26 UTC (permalink / raw)
  To: Will Deacon
  Cc: linux-kernel, maco, gregkh, Matthias Maennich, Ard Biesheuvel,
	Catalin Marinas

+++ Will Deacon [11/09/19 13:26 +0100]:
>Commit 8651ec01daed ("module: add support for symbol namespaces.")
>broke linking for arm64 defconfig:
>
>  | lib/crypto/arc4.o: In function `__ksymtab_arc4_setkey':
>  | arc4.c:(___ksymtab+arc4_setkey+0x8): undefined reference to `no symbol'
>  | lib/crypto/arc4.o: In function `__ksymtab_arc4_crypt':
>  | arc4.c:(___ksymtab+arc4_crypt+0x8): undefined reference to `no symbol'
>
>This is because the dummy initialisation of the 'namespace_offset' field
>in 'struct kernel_symbol' when using EXPORT_SYMBOL on architectures with
>support for PREL32 locations uses an offset from an absolute address (0)
>in an effort to trick 'offset_to_pointer' into behaving as a NOP,
>allowing non-namespaced symbols to be treated in the same way as those
>belonging to a namespace.
>
>Unfortunately, place-relative relocations require a symbol reference
>rather than an absolute value and, although x86 appears to get away with
>this due to placing the kernel text at the top of the address space, it
>almost certainly results in a runtime failure if the kernel is relocated
>dynamically as a result of KASLR.
>
>Rework 'namespace_offset' so that a value of 0, which cannot occur for a
>valid namespaced symbol, indicates that the corresponding symbol does
>not belong to a namespace.
>
>Cc: Matthias Maennich <maennich@google.com>
>Cc: Jessica Yu <jeyu@kernel.org>
>Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>Cc: Catalin Marinas <catalin.marinas@arm.com>
>Fixes: 8651ec01daed ("module: add support for symbol namespaces.")
>Reported-by: kbuild test robot <lkp@intel.com>
>Signed-off-by: Will Deacon <will@kernel.org>

Applied, thanks everyone!

Jessica

>---
>
>Please note that I've not been able to test this at LPC, but it's been
>submitted to kernelci.
>
> include/asm-generic/export.h | 2 +-
> include/linux/export.h       | 2 +-
> kernel/module.c              | 2 ++
> 3 files changed, 4 insertions(+), 2 deletions(-)
>
>diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
>index e2b5d0f569d3..d0912c7ac2fc 100644
>--- a/include/asm-generic/export.h
>+++ b/include/asm-generic/export.h
>@@ -17,7 +17,7 @@
>
> .macro __put, val, name
> #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
>-	.long	\val - ., \name - ., 0 - .
>+	.long	\val - ., \name - ., 0
> #elif defined(CONFIG_64BIT)
> 	.quad	\val, \name, 0
> #else
>diff --git a/include/linux/export.h b/include/linux/export.h
>index 2c5468d8ea9a..ef5d015d754a 100644
>--- a/include/linux/export.h
>+++ b/include/linux/export.h
>@@ -68,7 +68,7 @@ extern struct module __this_module;
> 	    "__ksymtab_" #sym ":				\n"	\
> 	    "	.long	" #sym "- .				\n"	\
> 	    "	.long	__kstrtab_" #sym "- .			\n"	\
>-	    "	.long	0 - .					\n"	\
>+	    "	.long	0					\n"	\
> 	    "	.previous					\n")
>
> struct kernel_symbol {
>diff --git a/kernel/module.c b/kernel/module.c
>index f76efcf2043e..7ab244c4e1ba 100644
>--- a/kernel/module.c
>+++ b/kernel/module.c
>@@ -547,6 +547,8 @@ static const char *kernel_symbol_name(const struct kernel_symbol *sym)
> static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
> {
> #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
>+	if (!sym->namespace_offset)
>+		return NULL;
> 	return offset_to_ptr(&sym->namespace_offset);
> #else
> 	return sym->namespace;
>-- 
>2.23.0.162.g0b9fbb3734-goog
>

^ permalink raw reply	[flat|nested] 6+ messages in thread

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2019-09-11 12:26 [PATCH] module: Fix link failure due to invalid relocation on namespace offset Will Deacon
2019-09-11 13:35 ` Jessica Yu
2019-09-11 16:40   ` Will Deacon
2019-09-11 16:53     ` Matthias Maennich
2019-09-11 16:51 ` Ard Biesheuvel
2019-09-11 18:26 ` Jessica Yu

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org linux-kernel@archiver.kernel.org
	public-inbox-index lkml


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox