* FAILED: patch "[PATCH] kho: init alloc tags when restoring pages from reserved" failed to apply to 6.18-stable tree
@ 2026-02-03 14:30 gregkh
2026-02-04 0:26 ` [PATCH 6.18.y] kho: init alloc tags when restoring pages from reserved memory Sasha Levin
0 siblings, 1 reply; 8+ messages in thread
From: gregkh @ 2026-02-03 14:30 UTC (permalink / raw)
To: ran.xiaokai, akpm, graf, kent.overstreet, pasha.tatashin,
pratyush, rppt, stable, surenb
Cc: stable
The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x e86436ad0ad2a9aaf88802d69b68f02cbd1f04a9
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026020303-drippy-appliance-a74c@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e86436ad0ad2a9aaf88802d69b68f02cbd1f04a9 Mon Sep 17 00:00:00 2001
From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Date: Thu, 22 Jan 2026 13:27:40 +0000
Subject: [PATCH] kho: init alloc tags when restoring pages from reserved
memory
Memblock pages (including reserved memory) should have their allocation
tags initialized to CODETAG_EMPTY via clear_page_tag_ref() before being
released to the page allocator. When kho restores pages through
kho_restore_page(), missing this call causes mismatched
allocation/deallocation tracking and below warning message:
alloc_tag was not set
WARNING: include/linux/alloc_tag.h:164 at ___free_pages+0xb8/0x260, CPU#1: swapper/0/1
RIP: 0010:___free_pages+0xb8/0x260
kho_restore_vmalloc+0x187/0x2e0
kho_test_init+0x3c4/0xa30
do_one_initcall+0x62/0x2b0
kernel_init_freeable+0x25b/0x480
kernel_init+0x1a/0x1c0
ret_from_fork+0x2d1/0x360
Add missing clear_page_tag_ref() annotation in kho_restore_page() to
fix this.
Link: https://lkml.kernel.org/r/20260122132740.176468-1-ranxiaokai627@163.com
Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation")
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c
index d4482b6e3cae..96767b106cac 100644
--- a/kernel/liveupdate/kexec_handover.c
+++ b/kernel/liveupdate/kexec_handover.c
@@ -255,6 +255,14 @@ static struct page *kho_restore_page(phys_addr_t phys, bool is_folio)
if (is_folio && info.order)
prep_compound_page(page, info.order);
+ /* Always mark headpage's codetag as empty to avoid accounting mismatch */
+ clear_page_tag_ref(page);
+ if (!is_folio) {
+ /* Also do that for the non-compound tail pages */
+ for (unsigned int i = 1; i < nr_pages; i++)
+ clear_page_tag_ref(page + i);
+ }
+
adjust_managed_page_count(page, nr_pages);
return page;
}
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH 6.18.y] kho: init alloc tags when restoring pages from reserved memory
2026-02-03 14:30 FAILED: patch "[PATCH] kho: init alloc tags when restoring pages from reserved" failed to apply to 6.18-stable tree gregkh
@ 2026-02-04 0:26 ` Sasha Levin
2026-02-04 9:59 ` Greg KH
0 siblings, 1 reply; 8+ messages in thread
From: Sasha Levin @ 2026-02-04 0:26 UTC (permalink / raw)
To: stable
Cc: Ran Xiaokai, Pratyush Yadav, Pasha Tatashin,
Mike Rapoport (Microsoft), Alexander Graf, Kent Overstreet,
Suren Baghdasaryan, Andrew Morton, Sasha Levin
From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
[ Upstream commit e86436ad0ad2a9aaf88802d69b68f02cbd1f04a9 ]
Memblock pages (including reserved memory) should have their allocation
tags initialized to CODETAG_EMPTY via clear_page_tag_ref() before being
released to the page allocator. When kho restores pages through
kho_restore_page(), missing this call causes mismatched
allocation/deallocation tracking and below warning message:
alloc_tag was not set
WARNING: include/linux/alloc_tag.h:164 at ___free_pages+0xb8/0x260, CPU#1: swapper/0/1
RIP: 0010:___free_pages+0xb8/0x260
kho_restore_vmalloc+0x187/0x2e0
kho_test_init+0x3c4/0xa30
do_one_initcall+0x62/0x2b0
kernel_init_freeable+0x25b/0x480
kernel_init+0x1a/0x1c0
ret_from_fork+0x2d1/0x360
Add missing clear_page_tag_ref() annotation in kho_restore_page() to
fix this.
Link: https://lkml.kernel.org/r/20260122132740.176468-1-ranxiaokai627@163.com
Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation")
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/kexec_handover.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
index 03d12e27189fc..db08c1a2e1f80 100644
--- a/kernel/kexec_handover.c
+++ b/kernel/kexec_handover.c
@@ -260,6 +260,14 @@ static struct page *kho_restore_page(phys_addr_t phys)
if (info.order > 0)
prep_compound_page(page, info.order);
+ /* Always mark headpage's codetag as empty to avoid accounting mismatch */
+ clear_page_tag_ref(page);
+ if (!is_folio) {
+ /* Also do that for the non-compound tail pages */
+ for (unsigned int i = 1; i < nr_pages; i++)
+ clear_page_tag_ref(page + i);
+ }
+
adjust_managed_page_count(page, nr_pages);
return page;
}
--
2.51.0
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH 6.18.y] kho: init alloc tags when restoring pages from reserved memory
2026-02-04 0:26 ` [PATCH 6.18.y] kho: init alloc tags when restoring pages from reserved memory Sasha Levin
@ 2026-02-04 9:59 ` Greg KH
2026-02-04 16:46 ` Suren Baghdasaryan
0 siblings, 1 reply; 8+ messages in thread
From: Greg KH @ 2026-02-04 9:59 UTC (permalink / raw)
To: Sasha Levin
Cc: stable, Ran Xiaokai, Pratyush Yadav, Pasha Tatashin,
Mike Rapoport (Microsoft), Alexander Graf, Kent Overstreet,
Suren Baghdasaryan, Andrew Morton
On Tue, Feb 03, 2026 at 07:26:54PM -0500, Sasha Levin wrote:
> From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
>
> [ Upstream commit e86436ad0ad2a9aaf88802d69b68f02cbd1f04a9 ]
>
> Memblock pages (including reserved memory) should have their allocation
> tags initialized to CODETAG_EMPTY via clear_page_tag_ref() before being
> released to the page allocator. When kho restores pages through
> kho_restore_page(), missing this call causes mismatched
> allocation/deallocation tracking and below warning message:
>
> alloc_tag was not set
> WARNING: include/linux/alloc_tag.h:164 at ___free_pages+0xb8/0x260, CPU#1: swapper/0/1
> RIP: 0010:___free_pages+0xb8/0x260
> kho_restore_vmalloc+0x187/0x2e0
> kho_test_init+0x3c4/0xa30
> do_one_initcall+0x62/0x2b0
> kernel_init_freeable+0x25b/0x480
> kernel_init+0x1a/0x1c0
> ret_from_fork+0x2d1/0x360
>
> Add missing clear_page_tag_ref() annotation in kho_restore_page() to
> fix this.
>
> Link: https://lkml.kernel.org/r/20260122132740.176468-1-ranxiaokai627@163.com
> Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation")
> Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Cc: Alexander Graf <graf@amazon.com>
> Cc: Kent Overstreet <kent.overstreet@linux.dev>
> Cc: Suren Baghdasaryan <surenb@google.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> kernel/kexec_handover.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
> index 03d12e27189fc..db08c1a2e1f80 100644
> --- a/kernel/kexec_handover.c
> +++ b/kernel/kexec_handover.c
> @@ -260,6 +260,14 @@ static struct page *kho_restore_page(phys_addr_t phys)
> if (info.order > 0)
> prep_compound_page(page, info.order);
>
> + /* Always mark headpage's codetag as empty to avoid accounting mismatch */
> + clear_page_tag_ref(page);
> + if (!is_folio) {
> + /* Also do that for the non-compound tail pages */
> + for (unsigned int i = 1; i < nr_pages; i++)
> + clear_page_tag_ref(page + i);
> + }
> +
Breaks the build :(
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH 6.18.y] kho: init alloc tags when restoring pages from reserved memory
2026-02-04 9:59 ` Greg KH
@ 2026-02-04 16:46 ` Suren Baghdasaryan
2026-02-04 17:06 ` Greg KH
0 siblings, 1 reply; 8+ messages in thread
From: Suren Baghdasaryan @ 2026-02-04 16:46 UTC (permalink / raw)
To: Greg KH
Cc: Sasha Levin, stable, Ran Xiaokai, Pratyush Yadav, Pasha Tatashin,
Mike Rapoport (Microsoft), Alexander Graf, Kent Overstreet,
Andrew Morton
On Wed, Feb 4, 2026 at 1:59 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Tue, Feb 03, 2026 at 07:26:54PM -0500, Sasha Levin wrote:
> > From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> >
> > [ Upstream commit e86436ad0ad2a9aaf88802d69b68f02cbd1f04a9 ]
> >
> > Memblock pages (including reserved memory) should have their allocation
> > tags initialized to CODETAG_EMPTY via clear_page_tag_ref() before being
> > released to the page allocator. When kho restores pages through
> > kho_restore_page(), missing this call causes mismatched
> > allocation/deallocation tracking and below warning message:
> >
> > alloc_tag was not set
> > WARNING: include/linux/alloc_tag.h:164 at ___free_pages+0xb8/0x260, CPU#1: swapper/0/1
> > RIP: 0010:___free_pages+0xb8/0x260
> > kho_restore_vmalloc+0x187/0x2e0
> > kho_test_init+0x3c4/0xa30
> > do_one_initcall+0x62/0x2b0
> > kernel_init_freeable+0x25b/0x480
> > kernel_init+0x1a/0x1c0
> > ret_from_fork+0x2d1/0x360
> >
> > Add missing clear_page_tag_ref() annotation in kho_restore_page() to
> > fix this.
> >
> > Link: https://lkml.kernel.org/r/20260122132740.176468-1-ranxiaokai627@163.com
> > Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation")
> > Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> > Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
> > Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> > Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> > Cc: Alexander Graf <graf@amazon.com>
> > Cc: Kent Overstreet <kent.overstreet@linux.dev>
> > Cc: Suren Baghdasaryan <surenb@google.com>
> > Cc: <stable@vger.kernel.org>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > Signed-off-by: Sasha Levin <sashal@kernel.org>
> > ---
> > kernel/kexec_handover.c | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
> > index 03d12e27189fc..db08c1a2e1f80 100644
> > --- a/kernel/kexec_handover.c
> > +++ b/kernel/kexec_handover.c
> > @@ -260,6 +260,14 @@ static struct page *kho_restore_page(phys_addr_t phys)
> > if (info.order > 0)
> > prep_compound_page(page, info.order);
> >
> > + /* Always mark headpage's codetag as empty to avoid accounting mismatch */
> > + clear_page_tag_ref(page);
> > + if (!is_folio) {
> > + /* Also do that for the non-compound tail pages */
> > + for (unsigned int i = 1; i < nr_pages; i++)
> > + clear_page_tag_ref(page + i);
> > + }
> > +
>
> Breaks the build :(
Which config? I built both defconfig and CONFIG_MEM_ALLOC_PROFILING=y,
they didn't fail. Could you please send me your failing config?
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH 6.18.y] kho: init alloc tags when restoring pages from reserved memory
2026-02-04 16:46 ` Suren Baghdasaryan
@ 2026-02-04 17:06 ` Greg KH
2026-02-04 17:56 ` Sasha Levin
2026-02-05 3:30 ` ranxiaokai627
0 siblings, 2 replies; 8+ messages in thread
From: Greg KH @ 2026-02-04 17:06 UTC (permalink / raw)
To: Suren Baghdasaryan
Cc: Sasha Levin, stable, Ran Xiaokai, Pratyush Yadav, Pasha Tatashin,
Mike Rapoport (Microsoft), Alexander Graf, Kent Overstreet,
Andrew Morton
On Wed, Feb 04, 2026 at 08:46:35AM -0800, Suren Baghdasaryan wrote:
> On Wed, Feb 4, 2026 at 1:59 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Tue, Feb 03, 2026 at 07:26:54PM -0500, Sasha Levin wrote:
> > > From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> > >
> > > [ Upstream commit e86436ad0ad2a9aaf88802d69b68f02cbd1f04a9 ]
> > >
> > > Memblock pages (including reserved memory) should have their allocation
> > > tags initialized to CODETAG_EMPTY via clear_page_tag_ref() before being
> > > released to the page allocator. When kho restores pages through
> > > kho_restore_page(), missing this call causes mismatched
> > > allocation/deallocation tracking and below warning message:
> > >
> > > alloc_tag was not set
> > > WARNING: include/linux/alloc_tag.h:164 at ___free_pages+0xb8/0x260, CPU#1: swapper/0/1
> > > RIP: 0010:___free_pages+0xb8/0x260
> > > kho_restore_vmalloc+0x187/0x2e0
> > > kho_test_init+0x3c4/0xa30
> > > do_one_initcall+0x62/0x2b0
> > > kernel_init_freeable+0x25b/0x480
> > > kernel_init+0x1a/0x1c0
> > > ret_from_fork+0x2d1/0x360
> > >
> > > Add missing clear_page_tag_ref() annotation in kho_restore_page() to
> > > fix this.
> > >
> > > Link: https://lkml.kernel.org/r/20260122132740.176468-1-ranxiaokai627@163.com
> > > Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation")
> > > Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> > > Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
> > > Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> > > Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> > > Cc: Alexander Graf <graf@amazon.com>
> > > Cc: Kent Overstreet <kent.overstreet@linux.dev>
> > > Cc: Suren Baghdasaryan <surenb@google.com>
> > > Cc: <stable@vger.kernel.org>
> > > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > > Signed-off-by: Sasha Levin <sashal@kernel.org>
> > > ---
> > > kernel/kexec_handover.c | 8 ++++++++
> > > 1 file changed, 8 insertions(+)
> > >
> > > diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
> > > index 03d12e27189fc..db08c1a2e1f80 100644
> > > --- a/kernel/kexec_handover.c
> > > +++ b/kernel/kexec_handover.c
> > > @@ -260,6 +260,14 @@ static struct page *kho_restore_page(phys_addr_t phys)
> > > if (info.order > 0)
> > > prep_compound_page(page, info.order);
> > >
> > > + /* Always mark headpage's codetag as empty to avoid accounting mismatch */
> > > + clear_page_tag_ref(page);
> > > + if (!is_folio) {
> > > + /* Also do that for the non-compound tail pages */
> > > + for (unsigned int i = 1; i < nr_pages; i++)
> > > + clear_page_tag_ref(page + i);
> > > + }
> > > +
> >
> > Breaks the build :(
>
> Which config? I built both defconfig and CONFIG_MEM_ALLOC_PROFILING=y,
> they didn't fail. Could you please send me your failing config?
is_folio is not defined in this function, how are you even building this
file?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH 6.18.y] kho: init alloc tags when restoring pages from reserved memory
2026-02-04 17:06 ` Greg KH
@ 2026-02-04 17:56 ` Sasha Levin
2026-02-04 17:59 ` Suren Baghdasaryan
2026-02-05 3:30 ` ranxiaokai627
1 sibling, 1 reply; 8+ messages in thread
From: Sasha Levin @ 2026-02-04 17:56 UTC (permalink / raw)
To: Greg KH
Cc: Suren Baghdasaryan, stable, Ran Xiaokai, Pratyush Yadav,
Pasha Tatashin, Mike Rapoport (Microsoft), Alexander Graf,
Kent Overstreet, Andrew Morton
On Wed, Feb 04, 2026 at 06:06:16PM +0100, Greg KH wrote:
>On Wed, Feb 04, 2026 at 08:46:35AM -0800, Suren Baghdasaryan wrote:
>> On Wed, Feb 4, 2026 at 1:59 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>> >
>> > On Tue, Feb 03, 2026 at 07:26:54PM -0500, Sasha Levin wrote:
>> > > From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
>> > >
>> > > [ Upstream commit e86436ad0ad2a9aaf88802d69b68f02cbd1f04a9 ]
>> > >
>> > > Memblock pages (including reserved memory) should have their allocation
>> > > tags initialized to CODETAG_EMPTY via clear_page_tag_ref() before being
>> > > released to the page allocator. When kho restores pages through
>> > > kho_restore_page(), missing this call causes mismatched
>> > > allocation/deallocation tracking and below warning message:
>> > >
>> > > alloc_tag was not set
>> > > WARNING: include/linux/alloc_tag.h:164 at ___free_pages+0xb8/0x260, CPU#1: swapper/0/1
>> > > RIP: 0010:___free_pages+0xb8/0x260
>> > > kho_restore_vmalloc+0x187/0x2e0
>> > > kho_test_init+0x3c4/0xa30
>> > > do_one_initcall+0x62/0x2b0
>> > > kernel_init_freeable+0x25b/0x480
>> > > kernel_init+0x1a/0x1c0
>> > > ret_from_fork+0x2d1/0x360
>> > >
>> > > Add missing clear_page_tag_ref() annotation in kho_restore_page() to
>> > > fix this.
>> > >
>> > > Link: https://lkml.kernel.org/r/20260122132740.176468-1-ranxiaokai627@163.com
>> > > Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation")
>> > > Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
>> > > Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
>> > > Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
>> > > Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
>> > > Cc: Alexander Graf <graf@amazon.com>
>> > > Cc: Kent Overstreet <kent.overstreet@linux.dev>
>> > > Cc: Suren Baghdasaryan <surenb@google.com>
>> > > Cc: <stable@vger.kernel.org>
>> > > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>> > > Signed-off-by: Sasha Levin <sashal@kernel.org>
>> > > ---
>> > > kernel/kexec_handover.c | 8 ++++++++
>> > > 1 file changed, 8 insertions(+)
>> > >
>> > > diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
>> > > index 03d12e27189fc..db08c1a2e1f80 100644
>> > > --- a/kernel/kexec_handover.c
>> > > +++ b/kernel/kexec_handover.c
>> > > @@ -260,6 +260,14 @@ static struct page *kho_restore_page(phys_addr_t phys)
>> > > if (info.order > 0)
>> > > prep_compound_page(page, info.order);
>> > >
>> > > + /* Always mark headpage's codetag as empty to avoid accounting mismatch */
>> > > + clear_page_tag_ref(page);
>> > > + if (!is_folio) {
>> > > + /* Also do that for the non-compound tail pages */
>> > > + for (unsigned int i = 1; i < nr_pages; i++)
>> > > + clear_page_tag_ref(page + i);
>> > > + }
>> > > +
>> >
>> > Breaks the build :(
>>
>> Which config? I built both defconfig and CONFIG_MEM_ALLOC_PROFILING=y,
>> they didn't fail. Could you please send me your failing config?
>
>is_folio is not defined in this function, how are you even building this
>file?
This is a stupid issue I've hit last time too: allmodconfig sets
CONFIG_DEFERRED_STRUCT_PAGE_INIT=y which disables KHO.
I'll figure out a patch that still builds KHO if CONFIG_COMPILE_TEST is set,
unless someone beats be to it...
--
Thanks,
Sasha
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH 6.18.y] kho: init alloc tags when restoring pages from reserved memory
2026-02-04 17:56 ` Sasha Levin
@ 2026-02-04 17:59 ` Suren Baghdasaryan
0 siblings, 0 replies; 8+ messages in thread
From: Suren Baghdasaryan @ 2026-02-04 17:59 UTC (permalink / raw)
To: Sasha Levin
Cc: Greg KH, stable, Ran Xiaokai, Pratyush Yadav, Pasha Tatashin,
Mike Rapoport (Microsoft), Alexander Graf, Kent Overstreet,
Andrew Morton
On Wed, Feb 4, 2026 at 9:56 AM Sasha Levin <sashal@kernel.org> wrote:
>
> On Wed, Feb 04, 2026 at 06:06:16PM +0100, Greg KH wrote:
> >On Wed, Feb 04, 2026 at 08:46:35AM -0800, Suren Baghdasaryan wrote:
> >> On Wed, Feb 4, 2026 at 1:59 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >> >
> >> > On Tue, Feb 03, 2026 at 07:26:54PM -0500, Sasha Levin wrote:
> >> > > From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> >> > >
> >> > > [ Upstream commit e86436ad0ad2a9aaf88802d69b68f02cbd1f04a9 ]
> >> > >
> >> > > Memblock pages (including reserved memory) should have their allocation
> >> > > tags initialized to CODETAG_EMPTY via clear_page_tag_ref() before being
> >> > > released to the page allocator. When kho restores pages through
> >> > > kho_restore_page(), missing this call causes mismatched
> >> > > allocation/deallocation tracking and below warning message:
> >> > >
> >> > > alloc_tag was not set
> >> > > WARNING: include/linux/alloc_tag.h:164 at ___free_pages+0xb8/0x260, CPU#1: swapper/0/1
> >> > > RIP: 0010:___free_pages+0xb8/0x260
> >> > > kho_restore_vmalloc+0x187/0x2e0
> >> > > kho_test_init+0x3c4/0xa30
> >> > > do_one_initcall+0x62/0x2b0
> >> > > kernel_init_freeable+0x25b/0x480
> >> > > kernel_init+0x1a/0x1c0
> >> > > ret_from_fork+0x2d1/0x360
> >> > >
> >> > > Add missing clear_page_tag_ref() annotation in kho_restore_page() to
> >> > > fix this.
> >> > >
> >> > > Link: https://lkml.kernel.org/r/20260122132740.176468-1-ranxiaokai627@163.com
> >> > > Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation")
> >> > > Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> >> > > Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
> >> > > Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> >> > > Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> >> > > Cc: Alexander Graf <graf@amazon.com>
> >> > > Cc: Kent Overstreet <kent.overstreet@linux.dev>
> >> > > Cc: Suren Baghdasaryan <surenb@google.com>
> >> > > Cc: <stable@vger.kernel.org>
> >> > > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> >> > > Signed-off-by: Sasha Levin <sashal@kernel.org>
> >> > > ---
> >> > > kernel/kexec_handover.c | 8 ++++++++
> >> > > 1 file changed, 8 insertions(+)
> >> > >
> >> > > diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
> >> > > index 03d12e27189fc..db08c1a2e1f80 100644
> >> > > --- a/kernel/kexec_handover.c
> >> > > +++ b/kernel/kexec_handover.c
> >> > > @@ -260,6 +260,14 @@ static struct page *kho_restore_page(phys_addr_t phys)
> >> > > if (info.order > 0)
> >> > > prep_compound_page(page, info.order);
> >> > >
> >> > > + /* Always mark headpage's codetag as empty to avoid accounting mismatch */
> >> > > + clear_page_tag_ref(page);
> >> > > + if (!is_folio) {
> >> > > + /* Also do that for the non-compound tail pages */
> >> > > + for (unsigned int i = 1; i < nr_pages; i++)
> >> > > + clear_page_tag_ref(page + i);
> >> > > + }
> >> > > +
> >> >
> >> > Breaks the build :(
> >>
> >> Which config? I built both defconfig and CONFIG_MEM_ALLOC_PROFILING=y,
> >> they didn't fail. Could you please send me your failing config?
> >
> >is_folio is not defined in this function, how are you even building this
> >file?
>
> This is a stupid issue I've hit last time too: allmodconfig sets
> CONFIG_DEFERRED_STRUCT_PAGE_INIT=y which disables KHO.
Yeah, that's what hit me too. The file is not complied with defconfigs.
>
> I'll figure out a patch that still builds KHO if CONFIG_COMPILE_TEST is set,
> unless someone beats be to it...
>
> --
> Thanks,
> Sasha
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 6.18.y] kho: init alloc tags when restoring pages from reserved memory
2026-02-04 17:06 ` Greg KH
2026-02-04 17:56 ` Sasha Levin
@ 2026-02-05 3:30 ` ranxiaokai627
1 sibling, 0 replies; 8+ messages in thread
From: ranxiaokai627 @ 2026-02-05 3:30 UTC (permalink / raw)
To: gregkh
Cc: akpm, graf, kent.overstreet, pasha.tatashin, pratyush,
ran.xiaokai, rppt, sashal, stable, surenb
Hi, Greg
>On Wed, Feb 04, 2026 at 08:46:35AM -0800, Suren Baghdasaryan wrote:
>> On Wed, Feb 4, 2026 at 1:59?AM Greg KH <gregkh@linuxfoundation.org> wrote:
>> >
>> > On Tue, Feb 03, 2026 at 07:26:54PM -0500, Sasha Levin wrote:
>> > > From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
>> > >
>> > > [ Upstream commit e86436ad0ad2a9aaf88802d69b68f02cbd1f04a9 ]
>> > >
>> > > Memblock pages (including reserved memory) should have their allocation
>> > > tags initialized to CODETAG_EMPTY via clear_page_tag_ref() before being
>> > > released to the page allocator. When kho restores pages through
>> > > kho_restore_page(), missing this call causes mismatched
>> > > allocation/deallocation tracking and below warning message:
>> > >
>> > > alloc_tag was not set
>> > > WARNING: include/linux/alloc_tag.h:164 at ___free_pages+0xb8/0x260, CPU#1: swapper/0/1
>> > > RIP: 0010:___free_pages+0xb8/0x260
>> > > kho_restore_vmalloc+0x187/0x2e0
>> > > kho_test_init+0x3c4/0xa30
>> > > do_one_initcall+0x62/0x2b0
>> > > kernel_init_freeable+0x25b/0x480
>> > > kernel_init+0x1a/0x1c0
>> > > ret_from_fork+0x2d1/0x360
>> > >
>> > > Add missing clear_page_tag_ref() annotation in kho_restore_page() to
>> > > fix this.
>> > >
>> > > Link: https://lkml.kernel.org/r/20260122132740.176468-1-ranxiaokai627@163.com
>> > > Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation")
>> > > Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
>> > > Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
>> > > Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
>> > > Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
>> > > Cc: Alexander Graf <graf@amazon.com>
>> > > Cc: Kent Overstreet <kent.overstreet@linux.dev>
>> > > Cc: Suren Baghdasaryan <surenb@google.com>
>> > > Cc: <stable@vger.kernel.org>
>> > > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>> > > Signed-off-by: Sasha Levin <sashal@kernel.org>
>> > > ---
>> > > kernel/kexec_handover.c | 8 ++++++++
>> > > 1 file changed, 8 insertions(+)
>> > >
>> > > diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
>> > > index 03d12e27189fc..db08c1a2e1f80 100644
>> > > --- a/kernel/kexec_handover.c
>> > > +++ b/kernel/kexec_handover.c
>> > > @@ -260,6 +260,14 @@ static struct page *kho_restore_page(phys_addr_t phys)
>> > > if (info.order > 0)
>> > > prep_compound_page(page, info.order);
>> > >
>> > > + /* Always mark headpage's codetag as empty to avoid accounting mismatch */
>> > > + clear_page_tag_ref(page);
>> > > + if (!is_folio) {
>> > > + /* Also do that for the non-compound tail pages */
>> > > + for (unsigned int i = 1; i < nr_pages; i++)
>> > > + clear_page_tag_ref(page + i);
>> > > + }
>> > > +
>> >
>> > Breaks the build :(
>>
>> Which config? I built both defconfig and CONFIG_MEM_ALLOC_PROFILING=y,
>> they didn't fail. Could you please send me your failing config?
>
>is_folio is not defined in this function, how are you even building this
>file?
This fix is based on commit 7b71205ae112 0e90c7f6d41d282e26c00e9ee6a7.
Therefore we would need to backport that prerequisite commit first.
I'm not sure whether it's worth the effort for a stable backport ?
On a related note, Pratyush's series
https://lore.kernel.org/all/20260116112217.915803-3-pratyush@kernel.org/
is currently refactoring this code area.
Perhaps we should wait for that series to land upstream and directly user
Pratyush's code for the stable tree?
>thanks,
>
>greg k-h
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2026-02-05 3:31 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-02-03 14:30 FAILED: patch "[PATCH] kho: init alloc tags when restoring pages from reserved" failed to apply to 6.18-stable tree gregkh
2026-02-04 0:26 ` [PATCH 6.18.y] kho: init alloc tags when restoring pages from reserved memory Sasha Levin
2026-02-04 9:59 ` Greg KH
2026-02-04 16:46 ` Suren Baghdasaryan
2026-02-04 17:06 ` Greg KH
2026-02-04 17:56 ` Sasha Levin
2026-02-04 17:59 ` Suren Baghdasaryan
2026-02-05 3:30 ` ranxiaokai627
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