From: Dave Young <dyoung@redhat.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
Baoquan He <bhe@redhat.com>, Ingo Molnar <mingo@kernel.org>,
Mike Galbraith <efault@gmx.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
Andy Lutomirski <luto@amacapital.net>,
Borislav Petkov <bp@suse.de>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-mm@kvack.org, Vivek Goyal <vgoyal@redhat.com>,
kexec@lists.infradead.org
Subject: Re: [PATCH 4.14 023/159] mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y
Date: Fri, 12 Jan 2018 08:55:49 +0800 [thread overview]
Message-ID: <20180112005549.GA2265@dhcp-128-65.nay.redhat.com> (raw)
In-Reply-To: <20180110111603.56disgew7ipusgjy@black.fi.intel.com>
On 01/10/18 at 02:16pm, Kirill A. Shutemov wrote:
> On Wed, Jan 10, 2018 at 03:08:04AM +0000, Dave Young wrote:
> > On Tue, Jan 09, 2018 at 12:05:52PM +0300, Kirill A. Shutemov wrote:
> > > On Tue, Jan 09, 2018 at 03:24:40PM +0800, Dave Young wrote:
> > > > On 01/09/18 at 01:41pm, Baoquan He wrote:
> > > > > On 01/09/18 at 09:09am, Dave Young wrote:
> > > > >
> > > > > > As for the macro name, VMCOREINFO_SYMBOL_ARRAY sounds better.
> > >
> > > Yep, that's better.
> > >
> > > > > I still think using vmcoreinfo_append_str is better. Unless we replace
> > > > > all array variables with the newly added macro.
> > > > >
> > > > > vmcoreinfo_append_str("SYMBOL(mem_section)=%lx\n",
> > > > > (unsigned long)mem_section);
> > > >
> > > > I have no strong opinion, either change all array uses or just introduce
> > > > the macro and start to use it from now on if we have similar array
> > > > symbols.
> > >
> > > Do you need some action on my side or will you folks take care about this?
> >
> > I think Baoquan was suggesting to update all array users in current
> > code, if you can check every VMCOREINFO_SYMBOL and update all the arrays
> > he will be happy. But if can not do it easily I'm fine with a
> > VMCOREINFO_SYMBOL_ARRAY changes only now, we kdump people can do it
> > later as well.
>
> It seems it's the only array we have there. swapper_pg_dir is a potential
> candidate, but it's 'unsigned long' on arm.
>
> Below it patch with corrected macro name.
>
> Please, consider applying.
>
> From 70f3a84b97f2de98d1364f7b10b7a42a1d8e9968 Mon Sep 17 00:00:00 2001
> From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Date: Tue, 9 Jan 2018 02:55:47 +0300
> Subject: [PATCH] kdump: Write a 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 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")
> ---
> 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);
> --
> Kirill A. Shutemov
Acked-by: Dave Young <dyoung@redhat.com>
If stable kernel took the mem section commits, then should also cc
stable. Andrew, can you help to make this in 4.15?
Thanks
Dave
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next prev parent reply other threads:[~2018-01-12 0:56 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20171222084623.668990192@linuxfoundation.org>
2017-12-22 8:45 ` [PATCH 4.14 023/159] mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y Greg Kroah-Hartman
2017-12-22 14:18 ` Dan Rue
2017-12-22 14:52 ` Naresh Kamboju
2017-12-22 15:12 ` Greg Kroah-Hartman
2017-12-22 15:03 ` Greg Kroah-Hartman
2018-01-07 5:14 ` Mike Galbraith
2018-01-07 9:11 ` Greg Kroah-Hartman
2018-01-07 9:21 ` Mike Galbraith
2018-01-07 10:18 ` Michal Hocko
2018-01-07 10:42 ` Greg Kroah-Hartman
2018-01-07 12:44 ` Mike Galbraith
2018-01-07 13:23 ` Michal Hocko
2018-01-08 7:53 ` Greg Kroah-Hartman
2018-01-08 8:15 ` Mike Galbraith
2018-01-08 8:33 ` Greg Kroah-Hartman
2018-01-08 9:45 ` Mike Galbraith
2018-01-08 8:47 ` Michal Hocko
2018-01-08 9:10 ` Greg Kroah-Hartman
2018-01-08 9:27 ` Greg Kroah-Hartman
2018-01-08 16:04 ` Ingo Molnar
2018-01-08 17:46 ` Kirill A. Shutemov
2018-01-09 0:13 ` Kirill A. Shutemov
2018-01-09 1:09 ` Dave Young
2018-01-09 5:41 ` Baoquan He
2018-01-09 7:24 ` Dave Young
2018-01-09 9:05 ` Kirill A. Shutemov
2018-01-10 3:08 ` Dave Young
2018-01-10 11:16 ` Kirill A. Shutemov
2018-01-11 1:06 ` Baoquan He
2018-01-12 0:55 ` Dave Young [this message]
2018-01-15 5:57 ` Omar Sandoval
2018-01-16 8:36 ` Atsushi Kumagai
2018-01-09 3:44 ` Mike Galbraith
2018-02-07 9:25 ` Dou Liyang
2018-02-07 10:41 ` Kirill A. Shutemov
2018-02-07 10:45 ` Mike Galbraith
2018-02-07 12:00 ` Dou Liyang
2018-02-07 12:08 ` Baoquan He
2018-02-07 12:17 ` Dou Liyang
2018-02-07 12:27 ` Baoquan He
2018-02-07 12:34 ` Dou Liyang
2018-02-07 12:45 ` Baoquan He
2018-02-08 1:14 ` Dou Liyang
2018-02-08 1:23 ` Baoquan He
2018-02-08 1:44 ` Dou Liyang
2018-02-07 11:28 ` Baoquan He
2018-01-17 5:24 ` Baoquan He
2018-01-25 15:50 ` Kirill A. Shutemov
2018-01-26 2:48 ` Baoquan He
2017-12-22 8:45 ` [PATCH 4.14 024/159] x86/kasan: Use the same shadow offset for 4- and 5-level paging Greg Kroah-Hartman
2017-12-22 8:45 ` [PATCH 4.14 025/159] x86/xen: Provide pre-built page tables only for CONFIG_XEN_PV=y and CONFIG_XEN_PVH=y Greg Kroah-Hartman
2017-12-22 8:45 ` [PATCH 4.14 026/159] x86/xen: Drop 5-level paging support code from the XEN_PV code Greg Kroah-Hartman
2017-12-22 8:45 ` [PATCH 4.14 033/159] x86/boot: Relocate definition of the initial state of CR0 Greg Kroah-Hartman
2017-12-22 8:46 ` [PATCH 4.14 097/159] x86/paravirt: Dont patch flush_tlb_single Greg Kroah-Hartman
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