* [PATCH] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
@ 2022-05-05 7:01 Hyeonggon Yoo
2022-05-05 7:12 ` Marco Elver
` (2 more replies)
0 siblings, 3 replies; 12+ messages in thread
From: Hyeonggon Yoo @ 2022-05-05 7:01 UTC (permalink / raw)
To: Alexander Potapenko, Marco Elver, Dmitry Vyukov, Andrew Morton
Cc: linux-mm, linux-kernel, Hyeonggon Yoo
When kfence fails to initialize kfence pool, it frees the pool.
But it does not reset PG_slab flag and memcg_data of struct page.
Below is a BUG because of this. Let's fix it by resetting PG_slab
and memcg_data before free.
[ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06
[ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06
[ 0.089150] memcg:ffffffff94a475d1
[ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
[ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000
[ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1
[ 0.089152] page dumped because: page still charged to cgroup
[ 0.089153] Modules linked in:
[ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965
[ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
[ 0.089154] Call Trace:
[ 0.089155] <TASK>
[ 0.089155] dump_stack_lvl+0x49/0x5f
[ 0.089157] dump_stack+0x10/0x12
[ 0.089158] bad_page.cold+0x63/0x94
[ 0.089159] check_free_page_bad+0x66/0x70
[ 0.089160] __free_pages_ok+0x423/0x530
[ 0.089161] __free_pages_core+0x8e/0xa0
[ 0.089162] memblock_free_pages+0x10/0x12
[ 0.089164] memblock_free_late+0x8f/0xb9
[ 0.089165] kfence_init+0x68/0x92
[ 0.089166] start_kernel+0x789/0x992
[ 0.089167] x86_64_start_reservations+0x24/0x26
[ 0.089168] x86_64_start_kernel+0xa9/0xaf
[ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb
[ 0.089171] </TASK>
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
---
mm/kfence/core.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index a203747ad2c0..2ab3d473321e 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -642,6 +642,13 @@ static bool __init kfence_init_pool_early(void)
* fails for the first page, and therefore expect addr==__kfence_pool in
* most failure cases.
*/
+ for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
+ struct page *page;
+
+ page = virt_to_page(p);
+ page->memcg_data = 0;
+ __ClearPageSlab(page);
+ }
memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
__kfence_pool = NULL;
return false;
--
2.32.0
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
2022-05-05 7:01 [PATCH] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool Hyeonggon Yoo
@ 2022-05-05 7:12 ` Marco Elver
2022-05-05 7:19 ` Marco Elver
2022-05-05 7:39 ` [PATCH v2] " Hyeonggon Yoo
2022-05-05 10:57 ` [PATCH] " kernel test robot
2 siblings, 1 reply; 12+ messages in thread
From: Marco Elver @ 2022-05-05 7:12 UTC (permalink / raw)
To: Hyeonggon Yoo, Muchun Song
Cc: Alexander Potapenko, Dmitry Vyukov, Andrew Morton, linux-mm,
linux-kernel
On Thu, 5 May 2022 at 09:01, Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote:
>
> When kfence fails to initialize kfence pool, it frees the pool.
> But it does not reset PG_slab flag and memcg_data of struct page.
>
> Below is a BUG because of this. Let's fix it by resetting PG_slab
> and memcg_data before free.
>
> [ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06
> [ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06
> [ 0.089150] memcg:ffffffff94a475d1
> [ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
> [ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000
> [ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1
> [ 0.089152] page dumped because: page still charged to cgroup
> [ 0.089153] Modules linked in:
> [ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965
> [ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
> [ 0.089154] Call Trace:
> [ 0.089155] <TASK>
> [ 0.089155] dump_stack_lvl+0x49/0x5f
> [ 0.089157] dump_stack+0x10/0x12
> [ 0.089158] bad_page.cold+0x63/0x94
> [ 0.089159] check_free_page_bad+0x66/0x70
> [ 0.089160] __free_pages_ok+0x423/0x530
> [ 0.089161] __free_pages_core+0x8e/0xa0
> [ 0.089162] memblock_free_pages+0x10/0x12
> [ 0.089164] memblock_free_late+0x8f/0xb9
> [ 0.089165] kfence_init+0x68/0x92
> [ 0.089166] start_kernel+0x789/0x992
> [ 0.089167] x86_64_start_reservations+0x24/0x26
> [ 0.089168] x86_64_start_kernel+0xa9/0xaf
> [ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb
> [ 0.089171] </TASK>
This is probably:
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> ---
> mm/kfence/core.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> index a203747ad2c0..2ab3d473321e 100644
> --- a/mm/kfence/core.c
> +++ b/mm/kfence/core.c
> @@ -642,6 +642,13 @@ static bool __init kfence_init_pool_early(void)
> * fails for the first page, and therefore expect addr==__kfence_pool in
> * most failure cases.
> */
> + for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
> + struct page *page;
> +
> + page = virt_to_page(p);
#ifdef CONFIG_MEMCG
> + page->memcg_data = 0;
#endif
> + __ClearPageSlab(page);
We're now using __folio_set_slab(), so I'm guessing this should be
__folio_clear_slab()?
> + }
> memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
> __kfence_pool = NULL;
> return false;
> --
> 2.32.0
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
2022-05-05 7:12 ` Marco Elver
@ 2022-05-05 7:19 ` Marco Elver
2022-05-05 7:27 ` Hyeonggon Yoo
0 siblings, 1 reply; 12+ messages in thread
From: Marco Elver @ 2022-05-05 7:19 UTC (permalink / raw)
To: Hyeonggon Yoo, Muchun Song
Cc: Alexander Potapenko, Dmitry Vyukov, Andrew Morton, linux-mm,
linux-kernel
On Thu, 5 May 2022 at 09:12, Marco Elver <elver@google.com> wrote:
>
> On Thu, 5 May 2022 at 09:01, Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote:
> >
> > When kfence fails to initialize kfence pool, it frees the pool.
> > But it does not reset PG_slab flag and memcg_data of struct page.
> >
> > Below is a BUG because of this. Let's fix it by resetting PG_slab
> > and memcg_data before free.
> >
> > [ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06
> > [ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06
> > [ 0.089150] memcg:ffffffff94a475d1
> > [ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
> > [ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000
> > [ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1
> > [ 0.089152] page dumped because: page still charged to cgroup
> > [ 0.089153] Modules linked in:
> > [ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965
> > [ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
> > [ 0.089154] Call Trace:
> > [ 0.089155] <TASK>
> > [ 0.089155] dump_stack_lvl+0x49/0x5f
> > [ 0.089157] dump_stack+0x10/0x12
> > [ 0.089158] bad_page.cold+0x63/0x94
> > [ 0.089159] check_free_page_bad+0x66/0x70
> > [ 0.089160] __free_pages_ok+0x423/0x530
> > [ 0.089161] __free_pages_core+0x8e/0xa0
> > [ 0.089162] memblock_free_pages+0x10/0x12
> > [ 0.089164] memblock_free_late+0x8f/0xb9
> > [ 0.089165] kfence_init+0x68/0x92
> > [ 0.089166] start_kernel+0x789/0x992
> > [ 0.089167] x86_64_start_reservations+0x24/0x26
> > [ 0.089168] x86_64_start_kernel+0xa9/0xaf
> > [ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb
> > [ 0.089171] </TASK>
>
> This is probably:
>
> Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Hmm, looking closer at the above BUG, I think it's
Fixes: 8f0b36497303 ("mm: kfence: fix objcgs vector allocation")
?
> > Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > ---
> > mm/kfence/core.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> > index a203747ad2c0..2ab3d473321e 100644
> > --- a/mm/kfence/core.c
> > +++ b/mm/kfence/core.c
> > @@ -642,6 +642,13 @@ static bool __init kfence_init_pool_early(void)
> > * fails for the first page, and therefore expect addr==__kfence_pool in
> > * most failure cases.
> > */
> > + for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
> > + struct page *page;
> > +
> > + page = virt_to_page(p);
>
> #ifdef CONFIG_MEMCG
>
> > + page->memcg_data = 0;
>
> #endif
>
> > + __ClearPageSlab(page);
>
> We're now using __folio_set_slab(), so I'm guessing this should be
> __folio_clear_slab()?
>
> > + }
> > memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
> > __kfence_pool = NULL;
> > return false;
> > --
> > 2.32.0
> >
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
2022-05-05 7:19 ` Marco Elver
@ 2022-05-05 7:27 ` Hyeonggon Yoo
0 siblings, 0 replies; 12+ messages in thread
From: Hyeonggon Yoo @ 2022-05-05 7:27 UTC (permalink / raw)
To: Marco Elver
Cc: Muchun Song, Alexander Potapenko, Dmitry Vyukov, Andrew Morton,
linux-mm, linux-kernel
On Thu, May 05, 2022 at 09:19:31AM +0200, Marco Elver wrote:
> On Thu, 5 May 2022 at 09:12, Marco Elver <elver@google.com> wrote:
> >
> > On Thu, 5 May 2022 at 09:01, Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote:
> > >
> > > When kfence fails to initialize kfence pool, it frees the pool.
> > > But it does not reset PG_slab flag and memcg_data of struct page.
> > >
> > > Below is a BUG because of this. Let's fix it by resetting PG_slab
> > > and memcg_data before free.
> > >
> > > [ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06
> > > [ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06
> > > [ 0.089150] memcg:ffffffff94a475d1
> > > [ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
> > > [ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000
> > > [ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1
> > > [ 0.089152] page dumped because: page still charged to cgroup
> > > [ 0.089153] Modules linked in:
> > > [ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965
> > > [ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
> > > [ 0.089154] Call Trace:
> > > [ 0.089155] <TASK>
> > > [ 0.089155] dump_stack_lvl+0x49/0x5f
> > > [ 0.089157] dump_stack+0x10/0x12
> > > [ 0.089158] bad_page.cold+0x63/0x94
> > > [ 0.089159] check_free_page_bad+0x66/0x70
> > > [ 0.089160] __free_pages_ok+0x423/0x530
> > > [ 0.089161] __free_pages_core+0x8e/0xa0
> > > [ 0.089162] memblock_free_pages+0x10/0x12
> > > [ 0.089164] memblock_free_late+0x8f/0xb9
> > > [ 0.089165] kfence_init+0x68/0x92
> > > [ 0.089166] start_kernel+0x789/0x992
> > > [ 0.089167] x86_64_start_reservations+0x24/0x26
> > > [ 0.089168] x86_64_start_kernel+0xa9/0xaf
> > > [ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb
> > > [ 0.089171] </TASK>
> >
> > This is probably:
> >
> > Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
>
> Hmm, looking closer at the above BUG, I think it's
>
> Fixes: 8f0b36497303 ("mm: kfence: fix objcgs vector allocation")
>
> ?
Marco, Thanks for comments.
I think it fixes both because not clearing PG_slab also invokes a BUG.
>
> > > Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > > ---
> > > mm/kfence/core.c | 7 +++++++
> > > 1 file changed, 7 insertions(+)
> > >
> > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> > > index a203747ad2c0..2ab3d473321e 100644
> > > --- a/mm/kfence/core.c
> > > +++ b/mm/kfence/core.c
> > > @@ -642,6 +642,13 @@ static bool __init kfence_init_pool_early(void)
> > > * fails for the first page, and therefore expect addr==__kfence_pool in
> > > * most failure cases.
> > > */
> > > + for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
> > > + struct page *page;
> > > +
> > > + page = virt_to_page(p);
> >
> > #ifdef CONFIG_MEMCG
> >
> > > + page->memcg_data = 0;
> >
> > #endif
> >
> > > + __ClearPageSlab(page);
> >
Ah, thanks! Will do in v2.
> > We're now using __folio_set_slab(), so I'm guessing this should be
> > __folio_clear_slab()?
Right. Will do in v2.
> >
> > > + }
> > > memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
> > > __kfence_pool = NULL;
> > > return false;
> > > --
> > > 2.32.0
> > >
--
Thanks,
Hyeonggon
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v2] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
2022-05-05 7:01 [PATCH] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool Hyeonggon Yoo
2022-05-05 7:12 ` Marco Elver
@ 2022-05-05 7:39 ` Hyeonggon Yoo
2022-05-05 8:25 ` Marco Elver
` (2 more replies)
2022-05-05 10:57 ` [PATCH] " kernel test robot
2 siblings, 3 replies; 12+ messages in thread
From: Hyeonggon Yoo @ 2022-05-05 7:39 UTC (permalink / raw)
To: Alexander Potapenko, Marco Elver, Dmitry Vyukov, Andrew Morton
Cc: linux-mm, linux-kernel, Hyeonggon Yoo
When kfence fails to initialize kfence pool, it frees the pool.
But it does not reset PG_slab flag and memcg_data of struct page.
Below is a BUG because of this. Let's fix it by resetting PG_slab
and memcg_data before free.
[ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06
[ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06
[ 0.089150] memcg:ffffffff94a475d1
[ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
[ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000
[ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1
[ 0.089152] page dumped because: page still charged to cgroup
[ 0.089153] Modules linked in:
[ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965
[ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
[ 0.089154] Call Trace:
[ 0.089155] <TASK>
[ 0.089155] dump_stack_lvl+0x49/0x5f
[ 0.089157] dump_stack+0x10/0x12
[ 0.089158] bad_page.cold+0x63/0x94
[ 0.089159] check_free_page_bad+0x66/0x70
[ 0.089160] __free_pages_ok+0x423/0x530
[ 0.089161] __free_pages_core+0x8e/0xa0
[ 0.089162] memblock_free_pages+0x10/0x12
[ 0.089164] memblock_free_late+0x8f/0xb9
[ 0.089165] kfence_init+0x68/0x92
[ 0.089166] start_kernel+0x789/0x992
[ 0.089167] x86_64_start_reservations+0x24/0x26
[ 0.089168] x86_64_start_kernel+0xa9/0xaf
[ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb
[ 0.089171] </TASK>
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Fixes: 8f0b36497303 ("mm: kfence: fix objcgs vector allocation")
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
---
v1 -> v2:
- Use folio instead of page
- Add Fixes: tags
- Wrap #ifdef ~ #endif around folio->memcg_data = 0;
mm/kfence/core.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index a203747ad2c0..bb1c6c489d0a 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -642,6 +642,15 @@ static bool __init kfence_init_pool_early(void)
* fails for the first page, and therefore expect addr==__kfence_pool in
* most failure cases.
*/
+ for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
+ struct folio *folio;
+
+ folio = virt_to_folio(p);
+ __folio_clear_slab(folio);
+#ifdef CONFIG_MEMCG
+ folio->memcg_data = 0;
+#endif
+ }
memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
__kfence_pool = NULL;
return false;
--
2.32.0
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH v2] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
2022-05-05 7:39 ` [PATCH v2] " Hyeonggon Yoo
@ 2022-05-05 8:25 ` Marco Elver
2022-05-05 9:07 ` Muchun Song
2022-05-05 10:13 ` [PATCH v3] " Hyeonggon Yoo
2 siblings, 0 replies; 12+ messages in thread
From: Marco Elver @ 2022-05-05 8:25 UTC (permalink / raw)
To: Hyeonggon Yoo
Cc: Alexander Potapenko, Dmitry Vyukov, Andrew Morton, linux-mm,
linux-kernel
On Thu, 5 May 2022 at 09:40, Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote:
>
> When kfence fails to initialize kfence pool, it frees the pool.
> But it does not reset PG_slab flag and memcg_data of struct page.
>
> Below is a BUG because of this. Let's fix it by resetting PG_slab
> and memcg_data before free.
>
> [ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06
> [ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06
> [ 0.089150] memcg:ffffffff94a475d1
> [ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
> [ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000
> [ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1
> [ 0.089152] page dumped because: page still charged to cgroup
> [ 0.089153] Modules linked in:
> [ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965
> [ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
> [ 0.089154] Call Trace:
> [ 0.089155] <TASK>
> [ 0.089155] dump_stack_lvl+0x49/0x5f
> [ 0.089157] dump_stack+0x10/0x12
> [ 0.089158] bad_page.cold+0x63/0x94
> [ 0.089159] check_free_page_bad+0x66/0x70
> [ 0.089160] __free_pages_ok+0x423/0x530
> [ 0.089161] __free_pages_core+0x8e/0xa0
> [ 0.089162] memblock_free_pages+0x10/0x12
> [ 0.089164] memblock_free_late+0x8f/0xb9
> [ 0.089165] kfence_init+0x68/0x92
> [ 0.089166] start_kernel+0x789/0x992
> [ 0.089167] x86_64_start_reservations+0x24/0x26
> [ 0.089168] x86_64_start_kernel+0xa9/0xaf
> [ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb
> [ 0.089171] </TASK>
>
> Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> Fixes: 8f0b36497303 ("mm: kfence: fix objcgs vector allocation")
> Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Reviewed-by: Marco Elver <elver@google.com>
, with small comment below.
> ---
>
> v1 -> v2:
> - Use folio instead of page
> - Add Fixes: tags
> - Wrap #ifdef ~ #endif around folio->memcg_data = 0;
>
> mm/kfence/core.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> index a203747ad2c0..bb1c6c489d0a 100644
> --- a/mm/kfence/core.c
> +++ b/mm/kfence/core.c
> @@ -642,6 +642,15 @@ static bool __init kfence_init_pool_early(void)
> * fails for the first page, and therefore expect addr==__kfence_pool in
> * most failure cases.
> */
> + for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
> + struct folio *folio;
> +
> + folio = virt_to_folio(p);
Assign folio where it is defined above. Better to always initialize
and guard against accidental uninit use in future.
Thanks,
-- Marco
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
2022-05-05 7:39 ` [PATCH v2] " Hyeonggon Yoo
2022-05-05 8:25 ` Marco Elver
@ 2022-05-05 9:07 ` Muchun Song
2022-05-05 10:13 ` [PATCH v3] " Hyeonggon Yoo
2 siblings, 0 replies; 12+ messages in thread
From: Muchun Song @ 2022-05-05 9:07 UTC (permalink / raw)
To: Hyeonggon Yoo
Cc: Alexander Potapenko, Marco Elver, Dmitry Vyukov, Andrew Morton,
linux-mm, linux-kernel
On Thu, May 05, 2022 at 04:39:20PM +0900, Hyeonggon Yoo wrote:
> When kfence fails to initialize kfence pool, it frees the pool.
> But it does not reset PG_slab flag and memcg_data of struct page.
>
> Below is a BUG because of this. Let's fix it by resetting PG_slab
> and memcg_data before free.
>
> [ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06
> [ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06
> [ 0.089150] memcg:ffffffff94a475d1
> [ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
> [ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000
> [ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1
> [ 0.089152] page dumped because: page still charged to cgroup
> [ 0.089153] Modules linked in:
> [ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965
> [ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
> [ 0.089154] Call Trace:
> [ 0.089155] <TASK>
> [ 0.089155] dump_stack_lvl+0x49/0x5f
> [ 0.089157] dump_stack+0x10/0x12
> [ 0.089158] bad_page.cold+0x63/0x94
> [ 0.089159] check_free_page_bad+0x66/0x70
> [ 0.089160] __free_pages_ok+0x423/0x530
> [ 0.089161] __free_pages_core+0x8e/0xa0
> [ 0.089162] memblock_free_pages+0x10/0x12
> [ 0.089164] memblock_free_late+0x8f/0xb9
> [ 0.089165] kfence_init+0x68/0x92
> [ 0.089166] start_kernel+0x789/0x992
> [ 0.089167] x86_64_start_reservations+0x24/0x26
> [ 0.089168] x86_64_start_kernel+0xa9/0xaf
> [ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb
> [ 0.089171] </TASK>
>
> Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> Fixes: 8f0b36497303 ("mm: kfence: fix objcgs vector allocation")
> Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Thanks.
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v3] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
2022-05-05 7:39 ` [PATCH v2] " Hyeonggon Yoo
2022-05-05 8:25 ` Marco Elver
2022-05-05 9:07 ` Muchun Song
@ 2022-05-05 10:13 ` Hyeonggon Yoo
2022-05-05 10:54 ` Muchun Song
2 siblings, 1 reply; 12+ messages in thread
From: Hyeonggon Yoo @ 2022-05-05 10:13 UTC (permalink / raw)
To: Alexander Potapenko, Marco Elver, Dmitry Vyukov, Andrew Morton
Cc: linux-mm, linux-kernel, Muchun Song, Hyeonggon Yoo
When kfence fails to initialize kfence pool, it frees the pool.
But it does not reset PG_slab flag and memcg_data of struct page.
Below is a BUG because of this. Let's fix it by resetting PG_slab
and memcg_data before free.
[ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06
[ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06
[ 0.089150] memcg:ffffffff94a475d1
[ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
[ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000
[ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1
[ 0.089152] page dumped because: page still charged to cgroup
[ 0.089153] Modules linked in:
[ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965
[ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
[ 0.089154] Call Trace:
[ 0.089155] <TASK>
[ 0.089155] dump_stack_lvl+0x49/0x5f
[ 0.089157] dump_stack+0x10/0x12
[ 0.089158] bad_page.cold+0x63/0x94
[ 0.089159] check_free_page_bad+0x66/0x70
[ 0.089160] __free_pages_ok+0x423/0x530
[ 0.089161] __free_pages_core+0x8e/0xa0
[ 0.089162] memblock_free_pages+0x10/0x12
[ 0.089164] memblock_free_late+0x8f/0xb9
[ 0.089165] kfence_init+0x68/0x92
[ 0.089166] start_kernel+0x789/0x992
[ 0.089167] x86_64_start_reservations+0x24/0x26
[ 0.089168] x86_64_start_kernel+0xa9/0xaf
[ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb
[ 0.089171] </TASK>
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Fixes: 8f0b36497303 ("mm: kfence: fix objcgs vector allocation")
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
---
v2 -> v3:
- Add Reviewed-by: tags from Marco and Muchun. Thanks!
- Initialize folio where it is defined.
mm/kfence/core.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index a203747ad2c0..b7d3a9667f00 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -642,6 +642,14 @@ static bool __init kfence_init_pool_early(void)
* fails for the first page, and therefore expect addr==__kfence_pool in
* most failure cases.
*/
+ for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
+ struct folio *folio = virt_to_folio(p);
+
+ __folio_clear_slab(folio);
+#ifdef CONFIG_MEMCG
+ folio->memcg_data = 0;
+#endif
+ }
memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
__kfence_pool = NULL;
return false;
--
2.32.0
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH v3] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
2022-05-05 10:13 ` [PATCH v3] " Hyeonggon Yoo
@ 2022-05-05 10:54 ` Muchun Song
2022-05-05 11:33 ` Hyeonggon Yoo
0 siblings, 1 reply; 12+ messages in thread
From: Muchun Song @ 2022-05-05 10:54 UTC (permalink / raw)
To: Hyeonggon Yoo
Cc: Alexander Potapenko, Marco Elver, Dmitry Vyukov, Andrew Morton,
linux-mm, linux-kernel
On Thu, May 05, 2022 at 07:13:37PM +0900, Hyeonggon Yoo wrote:
> When kfence fails to initialize kfence pool, it frees the pool.
> But it does not reset PG_slab flag and memcg_data of struct page.
>
> Below is a BUG because of this. Let's fix it by resetting PG_slab
> and memcg_data before free.
>
> [ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06
> [ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06
> [ 0.089150] memcg:ffffffff94a475d1
> [ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
> [ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000
> [ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1
> [ 0.089152] page dumped because: page still charged to cgroup
> [ 0.089153] Modules linked in:
> [ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965
> [ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
> [ 0.089154] Call Trace:
> [ 0.089155] <TASK>
> [ 0.089155] dump_stack_lvl+0x49/0x5f
> [ 0.089157] dump_stack+0x10/0x12
> [ 0.089158] bad_page.cold+0x63/0x94
> [ 0.089159] check_free_page_bad+0x66/0x70
> [ 0.089160] __free_pages_ok+0x423/0x530
> [ 0.089161] __free_pages_core+0x8e/0xa0
> [ 0.089162] memblock_free_pages+0x10/0x12
> [ 0.089164] memblock_free_late+0x8f/0xb9
> [ 0.089165] kfence_init+0x68/0x92
> [ 0.089166] start_kernel+0x789/0x992
> [ 0.089167] x86_64_start_reservations+0x24/0x26
> [ 0.089168] x86_64_start_kernel+0xa9/0xaf
> [ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb
> [ 0.089171] </TASK>
>
> Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> Fixes: 8f0b36497303 ("mm: kfence: fix objcgs vector allocation")
> Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Reviewed-by: Marco Elver <elver@google.com>
> Reviewed-by: Muchun Song <songmuchun@bytedance.com>
> ---
>
> v2 -> v3:
> - Add Reviewed-by: tags from Marco and Muchun. Thanks!
> - Initialize folio where it is defined.
>
> mm/kfence/core.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> index a203747ad2c0..b7d3a9667f00 100644
> --- a/mm/kfence/core.c
> +++ b/mm/kfence/core.c
> @@ -642,6 +642,14 @@ static bool __init kfence_init_pool_early(void)
> * fails for the first page, and therefore expect addr==__kfence_pool in
> * most failure cases.
> */
> + for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
> + struct folio *folio = virt_to_folio(p);
> +
After more thinking, I think it is better to use 'struct slab *'
to define a local variable since we already use this struct
throughout slab core. What do you think?
Thanks.
> + __folio_clear_slab(folio);
> +#ifdef CONFIG_MEMCG
> + folio->memcg_data = 0;
> +#endif
> + }
> memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
> __kfence_pool = NULL;
> return false;
> --
> 2.32.0
>
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
2022-05-05 7:01 [PATCH] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool Hyeonggon Yoo
2022-05-05 7:12 ` Marco Elver
2022-05-05 7:39 ` [PATCH v2] " Hyeonggon Yoo
@ 2022-05-05 10:57 ` kernel test robot
2 siblings, 0 replies; 12+ messages in thread
From: kernel test robot @ 2022-05-05 10:57 UTC (permalink / raw)
To: Hyeonggon Yoo, Alexander Potapenko, Marco Elver, Dmitry Vyukov,
Andrew Morton
Cc: kbuild-all, Linux Memory Management List, linux-kernel, Hyeonggon Yoo
Hi Hyeonggon,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on hnaz-mm/master]
url: https://github.com/intel-lab-lkp/linux/commits/Hyeonggon-Yoo/mm-kfence-reset-PG_slab-and-memcg_data-before-freeing-__kfence_pool/20220505-150237
base: https://github.com/hnaz/linux-mm master
config: s390-randconfig-r044-20220505 (https://download.01.org/0day-ci/archive/20220505/202205051852.M26PcwNj-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 11.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/ad166fcbcd464ea0251165580e1ea0152531fe56
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Hyeonggon-Yoo/mm-kfence-reset-PG_slab-and-memcg_data-before-freeing-__kfence_pool/20220505-150237
git checkout ad166fcbcd464ea0251165580e1ea0152531fe56
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash mm/kfence/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
mm/kfence/core.c: In function 'kfence_init_pool_early':
>> mm/kfence/core.c:634:21: error: 'struct page' has no member named 'memcg_data'
634 | page->memcg_data = 0;
| ^~
vim +634 mm/kfence/core.c
610
611 static bool __init kfence_init_pool_early(void)
612 {
613 unsigned long addr;
614
615 if (!__kfence_pool)
616 return false;
617
618 addr = kfence_init_pool();
619
620 if (!addr)
621 return true;
622
623 /*
624 * Only release unprotected pages, and do not try to go back and change
625 * page attributes due to risk of failing to do so as well. If changing
626 * page attributes for some pages fails, it is very likely that it also
627 * fails for the first page, and therefore expect addr==__kfence_pool in
628 * most failure cases.
629 */
630 for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
631 struct page *page;
632
633 page = virt_to_page(p);
> 634 page->memcg_data = 0;
635 __ClearPageSlab(page);
636 }
637 memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
638 __kfence_pool = NULL;
639 return false;
640 }
641
--
0-DAY CI Kernel Test Service
https://01.org/lkp
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v3] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
2022-05-05 10:54 ` Muchun Song
@ 2022-05-05 11:33 ` Hyeonggon Yoo
2022-05-05 12:00 ` Muchun Song
0 siblings, 1 reply; 12+ messages in thread
From: Hyeonggon Yoo @ 2022-05-05 11:33 UTC (permalink / raw)
To: Muchun Song
Cc: Alexander Potapenko, Marco Elver, Dmitry Vyukov, Andrew Morton,
linux-mm, linux-kernel
On Thu, May 05, 2022 at 06:54:18PM +0800, Muchun Song wrote:
> On Thu, May 05, 2022 at 07:13:37PM +0900, Hyeonggon Yoo wrote:
> > When kfence fails to initialize kfence pool, it frees the pool.
> > But it does not reset PG_slab flag and memcg_data of struct page.
> >
> > Below is a BUG because of this. Let's fix it by resetting PG_slab
> > and memcg_data before free.
> >
> > [ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06
> > [ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06
> > [ 0.089150] memcg:ffffffff94a475d1
> > [ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
> > [ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000
> > [ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1
> > [ 0.089152] page dumped because: page still charged to cgroup
> > [ 0.089153] Modules linked in:
> > [ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965
> > [ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
> > [ 0.089154] Call Trace:
> > [ 0.089155] <TASK>
> > [ 0.089155] dump_stack_lvl+0x49/0x5f
> > [ 0.089157] dump_stack+0x10/0x12
> > [ 0.089158] bad_page.cold+0x63/0x94
> > [ 0.089159] check_free_page_bad+0x66/0x70
> > [ 0.089160] __free_pages_ok+0x423/0x530
> > [ 0.089161] __free_pages_core+0x8e/0xa0
> > [ 0.089162] memblock_free_pages+0x10/0x12
> > [ 0.089164] memblock_free_late+0x8f/0xb9
> > [ 0.089165] kfence_init+0x68/0x92
> > [ 0.089166] start_kernel+0x789/0x992
> > [ 0.089167] x86_64_start_reservations+0x24/0x26
> > [ 0.089168] x86_64_start_kernel+0xa9/0xaf
> > [ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb
> > [ 0.089171] </TASK>
> >
> > Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> > Fixes: 8f0b36497303 ("mm: kfence: fix objcgs vector allocation")
> > Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > Reviewed-by: Marco Elver <elver@google.com>
> > Reviewed-by: Muchun Song <songmuchun@bytedance.com>
> > ---
> >
> > v2 -> v3:
> > - Add Reviewed-by: tags from Marco and Muchun. Thanks!
> > - Initialize folio where it is defined.
> >
> > mm/kfence/core.c | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> > index a203747ad2c0..b7d3a9667f00 100644
> > --- a/mm/kfence/core.c
> > +++ b/mm/kfence/core.c
> > @@ -642,6 +642,14 @@ static bool __init kfence_init_pool_early(void)
> > * fails for the first page, and therefore expect addr==__kfence_pool in
> > * most failure cases.
> > */
> > + for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
> > + struct folio *folio = virt_to_folio(p);
> > +
>
> After more thinking, I think it is better to use 'struct slab *'
> to define a local variable since we already use this struct
> throughout slab core. What do you think?
>
I think that may not be better.
In the code we're freeing folios (so not going to reuse it again in slab/kfence).
And it may not be Slab depending on why kfence_init_pool() failed.
> Thanks.
>
> > + __folio_clear_slab(folio);
> > +#ifdef CONFIG_MEMCG
> > + folio->memcg_data = 0;
> > +#endif
> > + }
> > memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
> > __kfence_pool = NULL;
> > return false;
> > --
> > 2.32.0
> >
> >
--
Thanks,
Hyeonggon
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v3] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool
2022-05-05 11:33 ` Hyeonggon Yoo
@ 2022-05-05 12:00 ` Muchun Song
0 siblings, 0 replies; 12+ messages in thread
From: Muchun Song @ 2022-05-05 12:00 UTC (permalink / raw)
To: Hyeonggon Yoo
Cc: Alexander Potapenko, Marco Elver, Dmitry Vyukov, Andrew Morton,
linux-mm, linux-kernel
On Thu, May 05, 2022 at 08:33:36PM +0900, Hyeonggon Yoo wrote:
> On Thu, May 05, 2022 at 06:54:18PM +0800, Muchun Song wrote:
> > On Thu, May 05, 2022 at 07:13:37PM +0900, Hyeonggon Yoo wrote:
> > > When kfence fails to initialize kfence pool, it frees the pool.
> > > But it does not reset PG_slab flag and memcg_data of struct page.
> > >
> > > Below is a BUG because of this. Let's fix it by resetting PG_slab
> > > and memcg_data before free.
> > >
> > > [ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06
> > > [ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06
> > > [ 0.089150] memcg:ffffffff94a475d1
> > > [ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
> > > [ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000
> > > [ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1
> > > [ 0.089152] page dumped because: page still charged to cgroup
> > > [ 0.089153] Modules linked in:
> > > [ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965
> > > [ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
> > > [ 0.089154] Call Trace:
> > > [ 0.089155] <TASK>
> > > [ 0.089155] dump_stack_lvl+0x49/0x5f
> > > [ 0.089157] dump_stack+0x10/0x12
> > > [ 0.089158] bad_page.cold+0x63/0x94
> > > [ 0.089159] check_free_page_bad+0x66/0x70
> > > [ 0.089160] __free_pages_ok+0x423/0x530
> > > [ 0.089161] __free_pages_core+0x8e/0xa0
> > > [ 0.089162] memblock_free_pages+0x10/0x12
> > > [ 0.089164] memblock_free_late+0x8f/0xb9
> > > [ 0.089165] kfence_init+0x68/0x92
> > > [ 0.089166] start_kernel+0x789/0x992
> > > [ 0.089167] x86_64_start_reservations+0x24/0x26
> > > [ 0.089168] x86_64_start_kernel+0xa9/0xaf
> > > [ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb
> > > [ 0.089171] </TASK>
> > >
> > > Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> > > Fixes: 8f0b36497303 ("mm: kfence: fix objcgs vector allocation")
> > > Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > > Reviewed-by: Marco Elver <elver@google.com>
> > > Reviewed-by: Muchun Song <songmuchun@bytedance.com>
> > > ---
> > >
> > > v2 -> v3:
> > > - Add Reviewed-by: tags from Marco and Muchun. Thanks!
> > > - Initialize folio where it is defined.
> > >
> > > mm/kfence/core.c | 8 ++++++++
> > > 1 file changed, 8 insertions(+)
> > >
> > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> > > index a203747ad2c0..b7d3a9667f00 100644
> > > --- a/mm/kfence/core.c
> > > +++ b/mm/kfence/core.c
> > > @@ -642,6 +642,14 @@ static bool __init kfence_init_pool_early(void)
> > > * fails for the first page, and therefore expect addr==__kfence_pool in
> > > * most failure cases.
> > > */
> > > + for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
> > > + struct folio *folio = virt_to_folio(p);
> > > +
> >
> > After more thinking, I think it is better to use 'struct slab *'
> > to define a local variable since we already use this struct
> > throughout slab core. What do you think?
> >
>
> I think that may not be better.
>
> In the code we're freeing folios (so not going to reuse it again in slab/kfence).
> And it may not be Slab depending on why kfence_init_pool() failed.
>
If it it not a Slab, then virt_to_slab() returns NULL in this case,
it is unnecessary to clear PG_slab and reset its ->memcg_data. Right?
Like the following changes:
diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 6e69986c3f0d..d90fe82dc752 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -627,6 +627,16 @@ static bool __init kfence_init_pool_early(void)
* fails for the first page, and therefore expect addr==__kfence_pool in
* most failure cases.
*/
+ for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
+ struct slab *slab = virt_to_slab(p);
+
+ if (!slab)
+ continue;
+ __folio_clear_slab(slab_folio(slab));
+#ifdef CONFIG_MEMCG
+ slab->memcg_data = 0;
+#endif
+ }
memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
__kfence_pool = NULL;
return false;
^ permalink raw reply related [flat|nested] 12+ messages in thread
end of thread, other threads:[~2022-05-05 12:00 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-05 7:01 [PATCH] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool Hyeonggon Yoo
2022-05-05 7:12 ` Marco Elver
2022-05-05 7:19 ` Marco Elver
2022-05-05 7:27 ` Hyeonggon Yoo
2022-05-05 7:39 ` [PATCH v2] " Hyeonggon Yoo
2022-05-05 8:25 ` Marco Elver
2022-05-05 9:07 ` Muchun Song
2022-05-05 10:13 ` [PATCH v3] " Hyeonggon Yoo
2022-05-05 10:54 ` Muchun Song
2022-05-05 11:33 ` Hyeonggon Yoo
2022-05-05 12:00 ` Muchun Song
2022-05-05 10:57 ` [PATCH] " kernel test robot
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