FAILED: patch "[PATCH] mm: kfence: fix using kfence_metadata without initialization" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] mm: kfence: fix using kfence_metadata without initialization" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 1c86a188e03156223a34d09ce290b49bd4dd0403
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '16800049118459@kroah.com' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

1c86a188e031 ("mm: kfence: fix using kfence_metadata without initialization in show_object()")
b33f778bba5e ("kfence: alloc kfence_pool after system startup")
698361bca2d5 ("kfence: allow re-enabling KFENCE after system startup")
07e8481d3c38 ("kfence: always use static branches to guard kfence_alloc()")
08f6b10630f2 ("kfence: limit currently covered allocations when pool nearly full")
a9ab52bbcb52 ("kfence: move saving stack trace of allocations into __kfence_alloc()")
9a19aeb56650 ("kfence: count unexpectedly skipped allocations")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 1c86a188e03156223a34d09ce290b49bd4dd0403 Mon Sep 17 00:00:00 2001
From: Muchun Song <muchun.song@linux.dev>
Date: Wed, 15 Mar 2023 11:44:41 +0800
Subject: [PATCH] mm: kfence: fix using kfence_metadata without initialization
 in show_object()

The variable kfence_metadata is initialized in kfence_init_pool(), then,
it is not initialized if kfence is disabled after booting.  In this case,
kfence_metadata will be used (e.g.  ->lock and ->state fields) without
initialization when reading /sys/kernel/debug/kfence/objects.  There will
be a warning if you enable CONFIG_DEBUG_SPINLOCK.  Fix it by creating
debugfs files when necessary.

Link: https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Tested-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 5349c37a5dac..79c94ee55f97 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -726,10 +726,14 @@ static const struct seq_operations objects_sops = {
 };
 DEFINE_SEQ_ATTRIBUTE(objects);
 
-static int __init kfence_debugfs_init(void)
+static int kfence_debugfs_init(void)
 {
-	struct dentry *kfence_dir = debugfs_create_dir("kfence", NULL);
+	struct dentry *kfence_dir;
 
+	if (!READ_ONCE(kfence_enabled))
+		return 0;
+
+	kfence_dir = debugfs_create_dir("kfence", NULL);
 	debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops);
 	debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops);
 	return 0;
@@ -883,6 +887,8 @@ static int kfence_init_late(void)
 	}
 
 	kfence_init_enable();
+	kfence_debugfs_init();
+
 	return 0;
 }
 

Re: FAILED: patch "[PATCH] mm: kfence: fix using kfence_metadata without initialization" failed to apply to 5.15-stable tree

[Muchun Song]

On 2023/3/28 20:01, gregkh@linuxfoundation.org wrote:
> The patch below does not apply to the 5.15-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-5.15.y
> git checkout FETCH_HEAD
> git cherry-pick -x 1c86a188e03156223a34d09ce290b49bd4dd0403
> # <resolve conflicts, build, test, etc.>
> git commit -s
> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '16800049118459@kroah.com' --subject-prefix 'PATCH 5.15.y' HEAD^..
>
> Possible dependencies:
>
> 1c86a188e031 ("mm: kfence: fix using kfence_metadata without initialization in show_object()")
> b33f778bba5e ("kfence: alloc kfence_pool after system startup")
> 698361bca2d5 ("kfence: allow re-enabling KFENCE after system startup")
> 07e8481d3c38 ("kfence: always use static branches to guard kfence_alloc()")
> 08f6b10630f2 ("kfence: limit currently covered allocations when pool nearly full")
> a9ab52bbcb52 ("kfence: move saving stack trace of allocations into __kfence_alloc()")
> 9a19aeb56650 ("kfence: count unexpectedly skipped allocations")
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
>  From 1c86a188e03156223a34d09ce290b49bd4dd0403 Mon Sep 17 00:00:00 2001
> From: Muchun Song <muchun.song@linux.dev>
> Date: Wed, 15 Mar 2023 11:44:41 +0800
> Subject: [PATCH] mm: kfence: fix using kfence_metadata without initialization
>   in show_object()
>
> The variable kfence_metadata is initialized in kfence_init_pool(), then,
> it is not initialized if kfence is disabled after booting.  In this case,
> kfence_metadata will be used (e.g.  ->lock and ->state fields) without
> initialization when reading /sys/kernel/debug/kfence/objects.  There will
> be a warning if you enable CONFIG_DEBUG_SPINLOCK.  Fix it by creating
> debugfs files when necessary.
>
> Link: https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com
> Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> Tested-by: Marco Elver <elver@google.com>
> Reviewed-by: Marco Elver <elver@google.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: Jann Horn <jannh@google.com>
> Cc: SeongJae Park <sjpark@amazon.de>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>
> diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> index 5349c37a5dac..79c94ee55f97 100644
> --- a/mm/kfence/core.c
> +++ b/mm/kfence/core.c
> @@ -726,10 +726,14 @@ static const struct seq_operations objects_sops = {
>   };
>   DEFINE_SEQ_ATTRIBUTE(objects);
>   
> -static int __init kfence_debugfs_init(void)
> +static int kfence_debugfs_init(void)
>   {
> -	struct dentry *kfence_dir = debugfs_create_dir("kfence", NULL);
> +	struct dentry *kfence_dir;
>   
> +	if (!READ_ONCE(kfence_enabled))
> +		return 0;
> +
> +	kfence_dir = debugfs_create_dir("kfence", NULL);
>   	debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops);
>   	debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops);
>   	return 0;
> @@ -883,6 +887,8 @@ static int kfence_init_late(void)
>   	}
>   
>   	kfence_init_enable();
> +	kfence_debugfs_init();
> +
>   	return 0;
>   }
>   

I have implemented a following patch based on v5.15 branch.

 From ba26f344fa3e477456a3cc60488a7b8e5af0e88d Mon Sep 17 00:00:00 2001
From: Muchun Song <songmuchun@bytedance.com>
Date: Wed, 15 Mar 2023 11:44:41 +0800
Subject: [PATCH] mm: kfence: fix using kfence_metadata without 
initialization
  in show_object()

The variable kfence_metadata is initialized in kfence_init_pool(), then,
it is not initialized if kfence is disabled after booting.  In this case,
kfence_metadata will be used (e.g.  ->lock and ->state fields) without
initialization when reading /sys/kernel/debug/kfence/objects.  There will
be a warning if you enable CONFIG_DEBUG_SPINLOCK.  Fix it by creating
debugfs files when necessary.

Link: 
https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Tested-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
  mm/kfence/core.c | 8 ++++++--
  1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 39a6c434e355..573f34e6af0b 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -678,10 +678,14 @@ static const struct file_operations objects_fops = {
      .release = seq_release,
  };

-static int __init kfence_debugfs_init(void)
+static int kfence_debugfs_init(void)
  {
-    struct dentry *kfence_dir = debugfs_create_dir("kfence", NULL);
+    struct dentry *kfence_dir;

+    if (!READ_ONCE(kfence_enabled))
+        return 0;
+
+    kfence_dir = debugfs_create_dir("kfence", NULL);
      debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops);
      debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops);
      return 0;
--
2.11.0

Re: FAILED: patch "[PATCH] mm: kfence: fix using kfence_metadata without initialization" failed to apply to 5.15-stable tree

[Greg KH]

On Tue, Mar 28, 2023 at 09:02:27PM +0800, Muchun Song wrote:
> 
> 
> On 2023/3/28 20:01, gregkh@linuxfoundation.org wrote:
> > The patch below does not apply to the 5.15-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-5.15.y
> > git checkout FETCH_HEAD
> > git cherry-pick -x 1c86a188e03156223a34d09ce290b49bd4dd0403
> > # <resolve conflicts, build, test, etc.>
> > git commit -s
> > git send-email --to '<stable@vger.kernel.org>' --in-reply-to '16800049118459@kroah.com' --subject-prefix 'PATCH 5.15.y' HEAD^..
> > 
> > Possible dependencies:
> > 
> > 1c86a188e031 ("mm: kfence: fix using kfence_metadata without initialization in show_object()")
> > b33f778bba5e ("kfence: alloc kfence_pool after system startup")
> > 698361bca2d5 ("kfence: allow re-enabling KFENCE after system startup")
> > 07e8481d3c38 ("kfence: always use static branches to guard kfence_alloc()")
> > 08f6b10630f2 ("kfence: limit currently covered allocations when pool nearly full")
> > a9ab52bbcb52 ("kfence: move saving stack trace of allocations into __kfence_alloc()")
> > 9a19aeb56650 ("kfence: count unexpectedly skipped allocations")
> > 
> > thanks,
> > 
> > greg k-h
> > 
> > ------------------ original commit in Linus's tree ------------------
> > 
> >  From 1c86a188e03156223a34d09ce290b49bd4dd0403 Mon Sep 17 00:00:00 2001
> > From: Muchun Song <muchun.song@linux.dev>
> > Date: Wed, 15 Mar 2023 11:44:41 +0800
> > Subject: [PATCH] mm: kfence: fix using kfence_metadata without initialization
> >   in show_object()
> > 
> > The variable kfence_metadata is initialized in kfence_init_pool(), then,
> > it is not initialized if kfence is disabled after booting.  In this case,
> > kfence_metadata will be used (e.g.  ->lock and ->state fields) without
> > initialization when reading /sys/kernel/debug/kfence/objects.  There will
> > be a warning if you enable CONFIG_DEBUG_SPINLOCK.  Fix it by creating
> > debugfs files when necessary.
> > 
> > Link: https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com
> > Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > Tested-by: Marco Elver <elver@google.com>
> > Reviewed-by: Marco Elver <elver@google.com>
> > Cc: Alexander Potapenko <glider@google.com>
> > Cc: Dmitry Vyukov <dvyukov@google.com>
> > Cc: Jann Horn <jannh@google.com>
> > Cc: SeongJae Park <sjpark@amazon.de>
> > Cc: <stable@vger.kernel.org>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > 
> > diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> > index 5349c37a5dac..79c94ee55f97 100644
> > --- a/mm/kfence/core.c
> > +++ b/mm/kfence/core.c
> > @@ -726,10 +726,14 @@ static const struct seq_operations objects_sops = {
> >   };
> >   DEFINE_SEQ_ATTRIBUTE(objects);
> > -static int __init kfence_debugfs_init(void)
> > +static int kfence_debugfs_init(void)
> >   {
> > -	struct dentry *kfence_dir = debugfs_create_dir("kfence", NULL);
> > +	struct dentry *kfence_dir;
> > +	if (!READ_ONCE(kfence_enabled))
> > +		return 0;
> > +
> > +	kfence_dir = debugfs_create_dir("kfence", NULL);
> >   	debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops);
> >   	debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops);
> >   	return 0;
> > @@ -883,6 +887,8 @@ static int kfence_init_late(void)
> >   	}
> >   	kfence_init_enable();
> > +	kfence_debugfs_init();
> > +
> >   	return 0;
> >   }
> 
> I have implemented a following patch based on v5.15 branch.
> 
> From ba26f344fa3e477456a3cc60488a7b8e5af0e88d Mon Sep 17 00:00:00 2001
> From: Muchun Song <songmuchun@bytedance.com>
> Date: Wed, 15 Mar 2023 11:44:41 +0800
> Subject: [PATCH] mm: kfence: fix using kfence_metadata without
> initialization
>  in show_object()
> 
> The variable kfence_metadata is initialized in kfence_init_pool(), then,
> it is not initialized if kfence is disabled after booting.  In this case,
> kfence_metadata will be used (e.g.  ->lock and ->state fields) without
> initialization when reading /sys/kernel/debug/kfence/objects.  There will
> be a warning if you enable CONFIG_DEBUG_SPINLOCK.  Fix it by creating
> debugfs files when necessary.
> 
> Link:
> https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com
> Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> Tested-by: Marco Elver <elver@google.com>
> Reviewed-by: Marco Elver <elver@google.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: Jann Horn <jannh@google.com>
> Cc: SeongJae Park <sjpark@amazon.de>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>  mm/kfence/core.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> index 39a6c434e355..573f34e6af0b 100644
> --- a/mm/kfence/core.c
> +++ b/mm/kfence/core.c
> @@ -678,10 +678,14 @@ static const struct file_operations objects_fops = {
>      .release = seq_release,
>  };
> 

Patch is corrupted with the whitespace eaten by your email client.  Can
you resend this in a format that it can be applied?

thanks,

greg k-h

Re: FAILED: patch "[PATCH] mm: kfence: fix using kfence_metadata without initialization" failed to apply to 5.15-stable tree

[Muchun Song]

[-- Attachment #1: Type: text/plain, Size: 5823 bytes --]



> On Mar 28, 2023, at 21:19, Greg KH <gregkh@linuxfoundation.org> wrote:
> 
> On Tue, Mar 28, 2023 at 09:02:27PM +0800, Muchun Song wrote:
>> 
>> 
>> On 2023/3/28 20:01, gregkh@linuxfoundation.org wrote:
>>> The patch below does not apply to the 5.15-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-5.15.y
>>> git checkout FETCH_HEAD
>>> git cherry-pick -x 1c86a188e03156223a34d09ce290b49bd4dd0403
>>> # <resolve conflicts, build, test, etc.>
>>> git commit -s
>>> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '16800049118459@kroah.com' --subject-prefix 'PATCH 5.15.y' HEAD^..
>>> 
>>> Possible dependencies:
>>> 
>>> 1c86a188e031 ("mm: kfence: fix using kfence_metadata without initialization in show_object()")
>>> b33f778bba5e ("kfence: alloc kfence_pool after system startup")
>>> 698361bca2d5 ("kfence: allow re-enabling KFENCE after system startup")
>>> 07e8481d3c38 ("kfence: always use static branches to guard kfence_alloc()")
>>> 08f6b10630f2 ("kfence: limit currently covered allocations when pool nearly full")
>>> a9ab52bbcb52 ("kfence: move saving stack trace of allocations into __kfence_alloc()")
>>> 9a19aeb56650 ("kfence: count unexpectedly skipped allocations")
>>> 
>>> thanks,
>>> 
>>> greg k-h
>>> 
>>> ------------------ original commit in Linus's tree ------------------
>>> 
>>> From 1c86a188e03156223a34d09ce290b49bd4dd0403 Mon Sep 17 00:00:00 2001
>>> From: Muchun Song <muchun.song@linux.dev>
>>> Date: Wed, 15 Mar 2023 11:44:41 +0800
>>> Subject: [PATCH] mm: kfence: fix using kfence_metadata without initialization
>>>  in show_object()
>>> 
>>> The variable kfence_metadata is initialized in kfence_init_pool(), then,
>>> it is not initialized if kfence is disabled after booting.  In this case,
>>> kfence_metadata will be used (e.g.  ->lock and ->state fields) without
>>> initialization when reading /sys/kernel/debug/kfence/objects.  There will
>>> be a warning if you enable CONFIG_DEBUG_SPINLOCK.  Fix it by creating
>>> debugfs files when necessary.
>>> 
>>> Link: https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com
>>> Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
>>> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
>>> Tested-by: Marco Elver <elver@google.com>
>>> Reviewed-by: Marco Elver <elver@google.com>
>>> Cc: Alexander Potapenko <glider@google.com>
>>> Cc: Dmitry Vyukov <dvyukov@google.com>
>>> Cc: Jann Horn <jannh@google.com>
>>> Cc: SeongJae Park <sjpark@amazon.de>
>>> Cc: <stable@vger.kernel.org>
>>> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>>> 
>>> diff --git a/mm/kfence/core.c b/mm/kfence/core.c
>>> index 5349c37a5dac..79c94ee55f97 100644
>>> --- a/mm/kfence/core.c
>>> +++ b/mm/kfence/core.c
>>> @@ -726,10 +726,14 @@ static const struct seq_operations objects_sops = {
>>>  };
>>>  DEFINE_SEQ_ATTRIBUTE(objects);
>>> -static int __init kfence_debugfs_init(void)
>>> +static int kfence_debugfs_init(void)
>>>  {
>>> - struct dentry *kfence_dir = debugfs_create_dir("kfence", NULL);
>>> + struct dentry *kfence_dir;
>>> + if (!READ_ONCE(kfence_enabled))
>>> + return 0;
>>> +
>>> + kfence_dir = debugfs_create_dir("kfence", NULL);
>>>   debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops);
>>>   debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops);
>>>   return 0;
>>> @@ -883,6 +887,8 @@ static int kfence_init_late(void)
>>>   }
>>>   kfence_init_enable();
>>> + kfence_debugfs_init();
>>> +
>>>   return 0;
>>>  }
>> 
>> I have implemented a following patch based on v5.15 branch.
>> 
>> From ba26f344fa3e477456a3cc60488a7b8e5af0e88d Mon Sep 17 00:00:00 2001
>> From: Muchun Song <songmuchun@bytedance.com>
>> Date: Wed, 15 Mar 2023 11:44:41 +0800
>> Subject: [PATCH] mm: kfence: fix using kfence_metadata without
>> initialization
>>  in show_object()
>> 
>> The variable kfence_metadata is initialized in kfence_init_pool(), then,
>> it is not initialized if kfence is disabled after booting.  In this case,
>> kfence_metadata will be used (e.g.  ->lock and ->state fields) without
>> initialization when reading /sys/kernel/debug/kfence/objects.  There will
>> be a warning if you enable CONFIG_DEBUG_SPINLOCK.  Fix it by creating
>> debugfs files when necessary.
>> 
>> Link:
>> https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com
>> Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
>> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
>> Tested-by: Marco Elver <elver@google.com>
>> Reviewed-by: Marco Elver <elver@google.com>
>> Cc: Alexander Potapenko <glider@google.com>
>> Cc: Dmitry Vyukov <dvyukov@google.com>
>> Cc: Jann Horn <jannh@google.com>
>> Cc: SeongJae Park <sjpark@amazon.de>
>> Cc: <stable@vger.kernel.org>
>> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>> ---
>>  mm/kfence/core.c | 8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>> 
>> diff --git a/mm/kfence/core.c b/mm/kfence/core.c
>> index 39a6c434e355..573f34e6af0b 100644
>> --- a/mm/kfence/core.c
>> +++ b/mm/kfence/core.c
>> @@ -678,10 +678,14 @@ static const struct file_operations objects_fops = {
>>      .release = seq_release,
>>  };
>> 
> 
> Patch is corrupted with the whitespace eaten by your email client.  Can
> you resend this in a format that it can be applied?

I attach it here. Could you apply it? Thanks.


[-- Attachment #2: 0001-mm-kfence-fix-using-kfence_metadata-without-initiali.patch --]
[-- Type: application/octet-stream, Size: 2000 bytes --]

From ba26f344fa3e477456a3cc60488a7b8e5af0e88d Mon Sep 17 00:00:00 2001
From: Muchun Song <songmuchun@bytedance.com>
Date: Wed, 15 Mar 2023 11:44:41 +0800
Subject: [PATCH] mm: kfence: fix using kfence_metadata without initialization
 in show_object()

The variable kfence_metadata is initialized in kfence_init_pool(), then,
it is not initialized if kfence is disabled after booting.  In this case,
kfence_metadata will be used (e.g.  ->lock and ->state fields) without
initialization when reading /sys/kernel/debug/kfence/objects.  There will
be a warning if you enable CONFIG_DEBUG_SPINLOCK.  Fix it by creating
debugfs files when necessary.

Link: https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Tested-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/kfence/core.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 39a6c434e355..573f34e6af0b 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -678,10 +678,14 @@ static const struct file_operations objects_fops = {
 	.release = seq_release,
 };
 
-static int __init kfence_debugfs_init(void)
+static int kfence_debugfs_init(void)
 {
-	struct dentry *kfence_dir = debugfs_create_dir("kfence", NULL);
+	struct dentry *kfence_dir;
 
+	if (!READ_ONCE(kfence_enabled))
+		return 0;
+
+	kfence_dir = debugfs_create_dir("kfence", NULL);
 	debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops);
 	debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops);
 	return 0;
-- 
2.11.0


[-- Attachment #3: Type: text/plain, Size: 30 bytes --]


> 
> thanks,
> 
> greg k-h

Re: FAILED: patch "[PATCH] mm: kfence: fix using kfence_metadata without initialization" failed to apply to 5.15-stable tree

[Greg KH]

On Tue, Mar 28, 2023 at 09:27:54PM +0800, Muchun Song wrote:
> 
> 
> > On Mar 28, 2023, at 21:19, Greg KH <gregkh@linuxfoundation.org> wrote:
> > 
> > On Tue, Mar 28, 2023 at 09:02:27PM +0800, Muchun Song wrote:
> >> 
> >> 
> >> On 2023/3/28 20:01, gregkh@linuxfoundation.org wrote:
> >>> The patch below does not apply to the 5.15-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-5.15.y
> >>> git checkout FETCH_HEAD
> >>> git cherry-pick -x 1c86a188e03156223a34d09ce290b49bd4dd0403
> >>> # <resolve conflicts, build, test, etc.>
> >>> git commit -s
> >>> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '16800049118459@kroah.com' --subject-prefix 'PATCH 5.15.y' HEAD^..
> >>> 
> >>> Possible dependencies:
> >>> 
> >>> 1c86a188e031 ("mm: kfence: fix using kfence_metadata without initialization in show_object()")
> >>> b33f778bba5e ("kfence: alloc kfence_pool after system startup")
> >>> 698361bca2d5 ("kfence: allow re-enabling KFENCE after system startup")
> >>> 07e8481d3c38 ("kfence: always use static branches to guard kfence_alloc()")
> >>> 08f6b10630f2 ("kfence: limit currently covered allocations when pool nearly full")
> >>> a9ab52bbcb52 ("kfence: move saving stack trace of allocations into __kfence_alloc()")
> >>> 9a19aeb56650 ("kfence: count unexpectedly skipped allocations")
> >>> 
> >>> thanks,
> >>> 
> >>> greg k-h
> >>> 
> >>> ------------------ original commit in Linus's tree ------------------
> >>> 
> >>> From 1c86a188e03156223a34d09ce290b49bd4dd0403 Mon Sep 17 00:00:00 2001
> >>> From: Muchun Song <muchun.song@linux.dev>
> >>> Date: Wed, 15 Mar 2023 11:44:41 +0800
> >>> Subject: [PATCH] mm: kfence: fix using kfence_metadata without initialization
> >>>  in show_object()
> >>> 
> >>> The variable kfence_metadata is initialized in kfence_init_pool(), then,
> >>> it is not initialized if kfence is disabled after booting.  In this case,
> >>> kfence_metadata will be used (e.g.  ->lock and ->state fields) without
> >>> initialization when reading /sys/kernel/debug/kfence/objects.  There will
> >>> be a warning if you enable CONFIG_DEBUG_SPINLOCK.  Fix it by creating
> >>> debugfs files when necessary.
> >>> 
> >>> Link: https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com
> >>> Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> >>> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> >>> Tested-by: Marco Elver <elver@google.com>
> >>> Reviewed-by: Marco Elver <elver@google.com>
> >>> Cc: Alexander Potapenko <glider@google.com>
> >>> Cc: Dmitry Vyukov <dvyukov@google.com>
> >>> Cc: Jann Horn <jannh@google.com>
> >>> Cc: SeongJae Park <sjpark@amazon.de>
> >>> Cc: <stable@vger.kernel.org>
> >>> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> >>> 
> >>> diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> >>> index 5349c37a5dac..79c94ee55f97 100644
> >>> --- a/mm/kfence/core.c
> >>> +++ b/mm/kfence/core.c
> >>> @@ -726,10 +726,14 @@ static const struct seq_operations objects_sops = {
> >>>  };
> >>>  DEFINE_SEQ_ATTRIBUTE(objects);
> >>> -static int __init kfence_debugfs_init(void)
> >>> +static int kfence_debugfs_init(void)
> >>>  {
> >>> - struct dentry *kfence_dir = debugfs_create_dir("kfence", NULL);
> >>> + struct dentry *kfence_dir;
> >>> + if (!READ_ONCE(kfence_enabled))
> >>> + return 0;
> >>> +
> >>> + kfence_dir = debugfs_create_dir("kfence", NULL);
> >>>   debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops);
> >>>   debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops);
> >>>   return 0;
> >>> @@ -883,6 +887,8 @@ static int kfence_init_late(void)
> >>>   }
> >>>   kfence_init_enable();
> >>> + kfence_debugfs_init();
> >>> +
> >>>   return 0;
> >>>  }
> >> 
> >> I have implemented a following patch based on v5.15 branch.
> >> 
> >> From ba26f344fa3e477456a3cc60488a7b8e5af0e88d Mon Sep 17 00:00:00 2001
> >> From: Muchun Song <songmuchun@bytedance.com>
> >> Date: Wed, 15 Mar 2023 11:44:41 +0800
> >> Subject: [PATCH] mm: kfence: fix using kfence_metadata without
> >> initialization
> >>  in show_object()
> >> 
> >> The variable kfence_metadata is initialized in kfence_init_pool(), then,
> >> it is not initialized if kfence is disabled after booting.  In this case,
> >> kfence_metadata will be used (e.g.  ->lock and ->state fields) without
> >> initialization when reading /sys/kernel/debug/kfence/objects.  There will
> >> be a warning if you enable CONFIG_DEBUG_SPINLOCK.  Fix it by creating
> >> debugfs files when necessary.
> >> 
> >> Link:
> >> https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com
> >> Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> >> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> >> Tested-by: Marco Elver <elver@google.com>
> >> Reviewed-by: Marco Elver <elver@google.com>
> >> Cc: Alexander Potapenko <glider@google.com>
> >> Cc: Dmitry Vyukov <dvyukov@google.com>
> >> Cc: Jann Horn <jannh@google.com>
> >> Cc: SeongJae Park <sjpark@amazon.de>
> >> Cc: <stable@vger.kernel.org>
> >> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> >> ---
> >>  mm/kfence/core.c | 8 ++++++--
> >>  1 file changed, 6 insertions(+), 2 deletions(-)
> >> 
> >> diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> >> index 39a6c434e355..573f34e6af0b 100644
> >> --- a/mm/kfence/core.c
> >> +++ b/mm/kfence/core.c
> >> @@ -678,10 +678,14 @@ static const struct file_operations objects_fops = {
> >>      .release = seq_release,
> >>  };
> >> 
> > 
> > Patch is corrupted with the whitespace eaten by your email client.  Can
> > you resend this in a format that it can be applied?
> 
> I attach it here. Could you apply it? Thanks.

That worked, thanks!