2008-08-12 21:24:30

by Marcin Ślusarz

[permalink] [raw]
Subject: [PATCH] x86: fix 2 section mismatch warnings - find_and_reserve_crashkernel

WARNING: vmlinux.o(.text+0xcd1f): Section mismatch in reference from the function find_and_reserve_crashkernel() to the function .init.text:find_e820_area()
The function find_and_reserve_crashkernel() references
the function __init find_e820_area().
This is often because find_and_reserve_crashkernel lacks a __init
annotation or the annotation of find_e820_area is wrong.

WARNING: vmlinux.o(.text+0xcd38): Section mismatch in reference from the function find_and_reserve_crashkernel() to the function .init.text:reserve_bootmem_generic()
The function find_and_reserve_crashkernel() references
the function __init reserve_bootmem_generic().
This is often because find_and_reserve_crashkernel lacks a __init
annotation or the annotation of reserve_bootmem_generic is wrong.

find_and_reserve_crashkernel is called from __init function (reserve_crashkernel)
and calls 2 __init functions (find_e820_area, reserve_bootmem_generic),
so mark it __init

Signed-off-by: Marcin Slusarz <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: H. Peter Anvin <[email protected]>
---
arch/x86/kernel/setup.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 68b48e3..a4656ad 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -445,7 +445,7 @@ static void __init reserve_early_setup_data(void)
* @size: Size of the crashkernel memory to reserve.
* Returns the base address on success, and -1ULL on failure.
*/
-unsigned long long find_and_reserve_crashkernel(unsigned long long size)
+unsigned long long __init find_and_reserve_crashkernel(unsigned long long size)
{
const unsigned long long alignment = 16<<20; /* 16M */
unsigned long long start = 0LL;
--
1.5.4.5


2008-08-13 11:11:18

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] x86: fix 2 section mismatch warnings - find_and_reserve_crashkernel


applied these fixes of yours to tip/x86/urgent:

# f0b0d88: x86: fix 2 section mismatch warnings - find_and_reserve_crashkernel
# 844342a: x86: fix section mismatch warning - spp_getpage()
# c9d08f0: x86: fix 2 section mismatch warnings - map_high()

thanks Marcin.

Ingo

2008-08-13 14:06:22

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] x86: fix 2 section mismatch warnings - find_and_reserve_crashkernel


* Ingo Molnar <[email protected]> wrote:

> # 844342a: x86: fix section mismatch warning - spp_getpage()

i've reverted this one as it's wrong and can cause crashes. For example
native_set_fixmap() gets called on 32-bit kernels from the ELF loader,
via arch_setup_additional_pages().

Ingo

2008-08-15 12:32:41

by Marcin Ślusarz

[permalink] [raw]
Subject: Re: [PATCH] x86: fix 2 section mismatch warnings - find_and_reserve_crashkernel

On Wed, Aug 13, 2008 at 04:05:55PM +0200, Ingo Molnar wrote:
>
> * Ingo Molnar <[email protected]> wrote:
>
> > # 844342a: x86: fix section mismatch warning - spp_getpage()
>
> i've reverted this one as it's wrong and can cause crashes. For example
> native_set_fixmap() gets called on 32-bit kernels from the ELF loader,
> via arch_setup_additional_pages().


$ git grep arch_setup_additional_pages | cat
arch/powerpc/include/asm/elf.h:/* vDSO has arch_setup_additional_pages */
arch/powerpc/include/asm/elf.h:extern int arch_setup_additional_pages(struct linux_binprm *bprm,
arch/powerpc/kernel/vdso.c:int arch_setup_additional_pages(struct linux_binprm *bprm,
arch/sh/include/asm/elf.h:/* vDSO has arch_setup_additional_pages */
arch/sh/include/asm/elf.h:extern int arch_setup_additional_pages(struct linux_binprm *bprm,
arch/sh/kernel/vsyscall/vsyscall.c:int arch_setup_additional_pages(struct linux_binprm *bprm,
arch/x86/vdso/vdso32-setup.c:#define arch_setup_additional_pages syscall32_setup_pages
arch/x86/vdso/vdso32-setup.c:int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack)
arch/x86/vdso/vma.c:int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack)
fs/binfmt_elf.c: retval = arch_setup_additional_pages(bprm, executable_stack);
fs/compat_binfmt_elf.c:#ifdef compat_arch_setup_additional_pages
fs/compat_binfmt_elf.c:#undef arch_setup_additional_pages
fs/compat_binfmt_elf.c:#define arch_setup_additional_pages compat_arch_setup_additional_pages
include/asm-x86/elf.h:extern int arch_setup_additional_pages(struct linux_binprm *bprm,
include/asm-x86/elf.h:#define compat_arch_setup_additional_pages syscall32_setup_pages

$ git grep native_set_fixmap | cat
arch/x86/kernel/paravirt.c: .set_fixmap = native_set_fixmap,
arch/x86/mm/pgtable.c:void __native_set_fixmap(enum fixed_addresses idx, pte_t pte)
arch/x86/mm/pgtable.c:void native_set_fixmap(enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
arch/x86/mm/pgtable.c: __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags));
arch/x86/xen/enlighten.c: __native_set_fixmap(idx, pte);
include/asm-x86/fixmap.h:void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
include/asm-x86/fixmap.h:void native_set_fixmap(enum fixed_addresses idx,
include/asm-x86/fixmap.h: native_set_fixmap(idx, phys, flags);

I looked at both implementations of arch_setup_additional_pages and didn't see any call to native_set_fixmap
or function which calls directly native_set_fixmap... Can you tell me what's the callchain?

Marcin

2008-08-15 13:50:51

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] x86: fix 2 section mismatch warnings - find_and_reserve_crashkernel


* Marcin Slusarz <[email protected]> wrote:

> I looked at both implementations of arch_setup_additional_pages and
> didn't see any call to native_set_fixmap or function which calls
> directly native_set_fixmap... Can you tell me what's the callchain?

the callchain would be:

[ 20.116039] PM: Adding info for No Bus:vcsa1
[ 20.180039] BUG: unable to handle kernel paging request at c0833e44
[ 20.180039] IP: [<c0833e44>] native_set_fixmap+0x0/0x1d
[ 20.180039] *pde = 36f2a163 *pte = 00833162
[ 20.180039] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
[ 20.180039] Modules linked in:
[ 20.180039]
[ 20.180039] Pid: 1, comm: init Not tainted (2.6.27-rc3-00005-g844342a-dirty #24071)
[ 20.180039] EIP: 0060:[<c0833e44>] EFLAGS: 00010216 CPU: 0
[ 20.180039] EIP is at native_set_fixmap+0x0/0x1d
[ 20.180039] EAX: 00000001 EBX: 00000001 ECX: 00000025 EDX: 3782e000
[ 20.180039] ESI: 00000000 EDI: f671c000 EBP: f7836e68 ESP: f7836e4c
[ 20.180039] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
[ 20.180039] Process init (pid: 1, ti=f7836000 task=f7870000 task.ti=f7836000)
[ 20.180039] Stack: c011d580 f671c034 c018bbea 00000025 00000000 00000988 f6ef2000 f7836f1c
[ 20.180039] c01b43d6 00000003 00000008 f7836f7c f782fd10 00000003 f78b6100 08048000
[ 20.180039] 00000000 00000001 f67a2500 08050b99 08050b99 00000000 00000000 00000000
[ 20.180039] Call Trace:
[ 20.180039] [<c011d580>] ? arch_setup_additional_pages+0x8c/0x124
[ 20.180039] [<c018bbea>] ? try_module_get+0x8/0x2f
[ 20.180039] [<c01b43d6>] ? load_elf_binary+0xae6/0x1108
[ 20.180039] [<c0144c6d>] ? lock_release_holdtime+0x43/0x48
[ 20.180039] [<c018c0c0>] ? search_binary_handler+0x92/0x1e5
[ 20.180039] [<c01b38f0>] ? load_elf_binary+0x0/0x1108
[ 20.180039] [<c018d2d7>] ? do_execve+0x14c/0x1d8
[ 20.180039] [<c0101dd8>] ? sys_execve+0x2e/0x56
[ 20.180039] [<c01030ca>] ? syscall_call+0x7/0xb
[ 20.180039] [<c01067c8>] ? kernel_execve+0x1c/0x21
[ 20.180039] [<c0101286>] ? run_init_process+0x1c/0x1e
[ 20.180039] [<c0101333>] ? init_post+0xab/0xd4
[ 20.180039] [<c0103d07>] ? kernel_thread_helper+0x7/0x10
[ 20.180039] =======================
[ 20.180039] Code: Bad EIP value.

Ingo

2008-08-15 16:33:33

by Marcin Ślusarz

[permalink] [raw]
Subject: [PATCH v2] x86: fix section mismatch warning - spp_getpage()

On Fri, Aug 15, 2008 at 03:50:27PM +0200, Ingo Molnar wrote:
>
> * Marcin Slusarz <[email protected]> wrote:
>
> > I looked at both implementations of arch_setup_additional_pages and
> > didn't see any call to native_set_fixmap or function which calls
> > directly native_set_fixmap... Can you tell me what's the callchain?
>
> the callchain would be:
>
> [ 20.116039] PM: Adding info for No Bus:vcsa1
> [ 20.180039] BUG: unable to handle kernel paging request at c0833e44
> [ 20.180039] IP: [<c0833e44>] native_set_fixmap+0x0/0x1d
> [ 20.180039] *pde = 36f2a163 *pte = 00833162
> [ 20.180039] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
> [ 20.180039] Modules linked in:
> [ 20.180039]
> [ 20.180039] Pid: 1, comm: init Not tainted (2.6.27-rc3-00005-g844342a-dirty #24071)
> [ 20.180039] EIP: 0060:[<c0833e44>] EFLAGS: 00010216 CPU: 0
> [ 20.180039] EIP is at native_set_fixmap+0x0/0x1d
> [ 20.180039] EAX: 00000001 EBX: 00000001 ECX: 00000025 EDX: 3782e000
> [ 20.180039] ESI: 00000000 EDI: f671c000 EBP: f7836e68 ESP: f7836e4c
> [ 20.180039] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
> [ 20.180039] Process init (pid: 1, ti=f7836000 task=f7870000 task.ti=f7836000)
> [ 20.180039] Stack: c011d580 f671c034 c018bbea 00000025 00000000 00000988 f6ef2000 f7836f1c
> [ 20.180039] c01b43d6 00000003 00000008 f7836f7c f782fd10 00000003 f78b6100 08048000
> [ 20.180039] 00000000 00000001 f67a2500 08050b99 08050b99 00000000 00000000 00000000
> [ 20.180039] Call Trace:
> [ 20.180039] [<c011d580>] ? arch_setup_additional_pages+0x8c/0x124
> [ 20.180039] [<c018bbea>] ? try_module_get+0x8/0x2f
> [ 20.180039] [<c01b43d6>] ? load_elf_binary+0xae6/0x1108
> [ 20.180039] [<c0144c6d>] ? lock_release_holdtime+0x43/0x48
> [ 20.180039] [<c018c0c0>] ? search_binary_handler+0x92/0x1e5
> [ 20.180039] [<c01b38f0>] ? load_elf_binary+0x0/0x1108
> [ 20.180039] [<c018d2d7>] ? do_execve+0x14c/0x1d8
> [ 20.180039] [<c0101dd8>] ? sys_execve+0x2e/0x56
> [ 20.180039] [<c01030ca>] ? syscall_call+0x7/0xb
> [ 20.180039] [<c01067c8>] ? kernel_execve+0x1c/0x21
> [ 20.180039] [<c0101286>] ? run_init_process+0x1c/0x1e
> [ 20.180039] [<c0101333>] ? init_post+0xab/0xd4
> [ 20.180039] [<c0103d07>] ? kernel_thread_helper+0x7/0x10
> [ 20.180039] =======================
> [ 20.180039] Code: Bad EIP value.
>
> Ingo

Thanks.
arch_setup_additional_pages -> map_compat_vdso -> __set_fixmap -> native_set_fixmap

How about this one?
---
From: Marcin Slusarz <[email protected]>
Subject: [PATCH v2] x86: fix section mismatch warning - spp_getpage()

WARNING: vmlinux.o(.text+0x17a3e): Section mismatch in reference from the function set_pte_vaddr_pud() to the function .init.text:spp_getpage()
The function set_pte_vaddr_pud() references
the function __init spp_getpage().
This is often because set_pte_vaddr_pud lacks a __init
annotation or the annotation of spp_getpage is wrong.

spp_getpage is called from __init (__init_extra_mapping) and
non __init (set_pte_vaddr_pud) functions, so it can't be __init.
Unfortunately it calls alloc_bootmem_pages which is __init,
but does it only when bootmem allocator is available (after_bootmem == 0).

Signed-off-by: Marcin Slusarz <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: H. Peter Anvin <[email protected]>
---
arch/x86/mm/init_64.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 129618c..f0923ce 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -88,7 +88,11 @@ early_param("gbpages", parse_direct_gbpages_on);

int after_bootmem;

-static __init void *spp_getpage(void)
+/*
+ * NOTE: This function is marked __ref because it calls __init function
+ * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
+ */
+static __ref void *spp_getpage(void)
{
void *ptr;

--
1.5.4.5

2008-08-15 17:15:20

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH v2] x86: fix section mismatch warning - spp_getpage()


* Marcin Slusarz <[email protected]> wrote:

> -static __init void *spp_getpage(void)
> +/*
> + * NOTE: This function is marked __ref because it calls __init function
> + * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
> + */
> +static __ref void *spp_getpage(void)

perfect - applied to tip/x86/urgent, thanks Marcin.

Ingo