diff mbox series

arm64: mm: don't use CON and BLK mapping if KFENCE is enabled

Message ID 20210524153659.58a707a9@xhacker.debian (mailing list archive)
State New, archived
Headers show
Series arm64: mm: don't use CON and BLK mapping if KFENCE is enabled | expand

Commit Message

Jisheng Zhang May 24, 2021, 7:36 a.m. UTC
Fix below warning if KFENCE=y but RODATA_FULL=n:

[    0.000000] ------------[ cut here ]------------
[    0.000000] WARNING: CPU: 0 PID: 0 at mm/memory.c:2462 apply_to_pmd_range+0xec/0x190
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.13.0-rc1+ #10
[    0.000000] Hardware name: linux,dummy-virt (DT)
[    0.000000] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO BTYPE=--)
[    0.000000] pc : apply_to_pmd_range+0xec/0x190
[    0.000000] lr : __apply_to_page_range+0x94/0x170
[    0.000000] sp : ffffffc010573e20
[    0.000000] x29: ffffffc010573e20 x28: ffffff801f400000 x27: ffffff801f401000
[    0.000000] x26: 0000000000000001 x25: ffffff801f400fff x24: ffffffc010573f28
[    0.000000] x23: ffffffc01002b710 x22: ffffffc0105fa450 x21: ffffffc010573ee4
[    0.000000] x20: ffffff801fffb7d0 x19: ffffff801f401000 x18: 00000000fffffffe
[    0.000000] x17: 000000000000003f x16: 000000000000000a x15: ffffffc01060b940
[    0.000000] x14: 0000000000000000 x13: 0098968000000000 x12: 0000000098968000
[    0.000000] x11: 0000000000000000 x10: 0000000098968000 x9 : 0000000000000001
[    0.000000] x8 : 0000000000000000 x7 : ffffffc010573ee4 x6 : 0000000000000001
[    0.000000] x5 : ffffffc010573f28 x4 : ffffffc01002b710 x3 : 0000000040000000
[    0.000000] x2 : ffffff801f5fffff x1 : 0000000000000001 x0 : 007800005f400705
[    0.000000] Call trace:
[    0.000000]  apply_to_pmd_range+0xec/0x190
[    0.000000]  __apply_to_page_range+0x94/0x170
[    0.000000]  apply_to_page_range+0x10/0x20
[    0.000000]  __change_memory_common+0x50/0xdc
[    0.000000]  set_memory_valid+0x30/0x40
[    0.000000]  kfence_init_pool+0x9c/0x16c
[    0.000000]  kfence_init+0x20/0x98
[    0.000000]  start_kernel+0x284/0x3f8

Fixes: 840b23986344 ("arm64, kfence: enable KFENCE for ARM64")
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
---
 arch/arm64/mm/mmu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Marco Elver May 24, 2021, 10:05 a.m. UTC | #1
On Mon, 24 May 2021 at 09:38, Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote:
>
> Fix below warning if KFENCE=y but RODATA_FULL=n:
>

Is this patch still relevant given you just sent "arm64: remove page
granularity limitation from KFENCE" ?

> [    0.000000] ------------[ cut here ]------------
> [    0.000000] WARNING: CPU: 0 PID: 0 at mm/memory.c:2462 apply_to_pmd_range+0xec/0x190
> [    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.13.0-rc1+ #10
> [    0.000000] Hardware name: linux,dummy-virt (DT)
> [    0.000000] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO BTYPE=--)
> [    0.000000] pc : apply_to_pmd_range+0xec/0x190
> [    0.000000] lr : __apply_to_page_range+0x94/0x170
> [    0.000000] sp : ffffffc010573e20
> [    0.000000] x29: ffffffc010573e20 x28: ffffff801f400000 x27: ffffff801f401000
> [    0.000000] x26: 0000000000000001 x25: ffffff801f400fff x24: ffffffc010573f28
> [    0.000000] x23: ffffffc01002b710 x22: ffffffc0105fa450 x21: ffffffc010573ee4
> [    0.000000] x20: ffffff801fffb7d0 x19: ffffff801f401000 x18: 00000000fffffffe
> [    0.000000] x17: 000000000000003f x16: 000000000000000a x15: ffffffc01060b940
> [    0.000000] x14: 0000000000000000 x13: 0098968000000000 x12: 0000000098968000
> [    0.000000] x11: 0000000000000000 x10: 0000000098968000 x9 : 0000000000000001
> [    0.000000] x8 : 0000000000000000 x7 : ffffffc010573ee4 x6 : 0000000000000001
> [    0.000000] x5 : ffffffc010573f28 x4 : ffffffc01002b710 x3 : 0000000040000000
> [    0.000000] x2 : ffffff801f5fffff x1 : 0000000000000001 x0 : 007800005f400705
> [    0.000000] Call trace:
> [    0.000000]  apply_to_pmd_range+0xec/0x190
> [    0.000000]  __apply_to_page_range+0x94/0x170
> [    0.000000]  apply_to_page_range+0x10/0x20
> [    0.000000]  __change_memory_common+0x50/0xdc
> [    0.000000]  set_memory_valid+0x30/0x40
> [    0.000000]  kfence_init_pool+0x9c/0x16c
> [    0.000000]  kfence_init+0x20/0x98
> [    0.000000]  start_kernel+0x284/0x3f8
>
> Fixes: 840b23986344 ("arm64, kfence: enable KFENCE for ARM64")
> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> ---
>  arch/arm64/mm/mmu.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 6dd9369e3ea0..89b66ef43a0f 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -515,7 +515,8 @@ static void __init map_mem(pgd_t *pgdp)
>          */
>         BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end));
>
> -       if (rodata_full || crash_mem_map || debug_pagealloc_enabled())
> +       if (rodata_full || crash_mem_map || debug_pagealloc_enabled() ||
> +           IS_ENABLED(CONFIG_KFENCE))
>                 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
>
>         /*
> --
> 2.31.0
>
Jisheng Zhang May 24, 2021, 10:09 a.m. UTC | #2
On Mon, 24 May 2021 12:05:21 +0200 Marco Elver wrote:

> 
> 
> On Mon, 24 May 2021 at 09:38, Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote:
> >
> > Fix below warning if KFENCE=y but RODATA_FULL=n:
> >  
> 
> Is this patch still relevant given you just sent "arm64: remove page
> granularity limitation from KFENCE" ?

This patch fixes a bug, so I suppose it needs to merged for linux-5.13-rcN
While the "arm64: remove page granularity limitation from KFENCE" series
is an optimization, so it need to wait for next version, I.E linux-5.14

thanks

> 
> > [    0.000000] ------------[ cut here ]------------
> > [    0.000000] WARNING: CPU: 0 PID: 0 at mm/memory.c:2462 apply_to_pmd_range+0xec/0x190
> > [    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.13.0-rc1+ #10
> > [    0.000000] Hardware name: linux,dummy-virt (DT)
> > [    0.000000] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO BTYPE=--)
> > [    0.000000] pc : apply_to_pmd_range+0xec/0x190
> > [    0.000000] lr : __apply_to_page_range+0x94/0x170
> > [    0.000000] sp : ffffffc010573e20
> > [    0.000000] x29: ffffffc010573e20 x28: ffffff801f400000 x27: ffffff801f401000
> > [    0.000000] x26: 0000000000000001 x25: ffffff801f400fff x24: ffffffc010573f28
> > [    0.000000] x23: ffffffc01002b710 x22: ffffffc0105fa450 x21: ffffffc010573ee4
> > [    0.000000] x20: ffffff801fffb7d0 x19: ffffff801f401000 x18: 00000000fffffffe
> > [    0.000000] x17: 000000000000003f x16: 000000000000000a x15: ffffffc01060b940
> > [    0.000000] x14: 0000000000000000 x13: 0098968000000000 x12: 0000000098968000
> > [    0.000000] x11: 0000000000000000 x10: 0000000098968000 x9 : 0000000000000001
> > [    0.000000] x8 : 0000000000000000 x7 : ffffffc010573ee4 x6 : 0000000000000001
> > [    0.000000] x5 : ffffffc010573f28 x4 : ffffffc01002b710 x3 : 0000000040000000
> > [    0.000000] x2 : ffffff801f5fffff x1 : 0000000000000001 x0 : 007800005f400705
> > [    0.000000] Call trace:
> > [    0.000000]  apply_to_pmd_range+0xec/0x190
> > [    0.000000]  __apply_to_page_range+0x94/0x170
> > [    0.000000]  apply_to_page_range+0x10/0x20
> > [    0.000000]  __change_memory_common+0x50/0xdc
> > [    0.000000]  set_memory_valid+0x30/0x40
> > [    0.000000]  kfence_init_pool+0x9c/0x16c
> > [    0.000000]  kfence_init+0x20/0x98
> > [    0.000000]  start_kernel+0x284/0x3f8
> >
> > Fixes: 840b23986344 ("arm64, kfence: enable KFENCE for ARM64")
> > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> > ---
> >  arch/arm64/mm/mmu.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> > index 6dd9369e3ea0..89b66ef43a0f 100644
> > --- a/arch/arm64/mm/mmu.c
> > +++ b/arch/arm64/mm/mmu.c
> > @@ -515,7 +515,8 @@ static void __init map_mem(pgd_t *pgdp)
> >          */
> >         BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end));
> >
> > -       if (rodata_full || crash_mem_map || debug_pagealloc_enabled())
> > +       if (rodata_full || crash_mem_map || debug_pagealloc_enabled() ||
> > +           IS_ENABLED(CONFIG_KFENCE))
> >                 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
> >
> >         /*
> > --
> > 2.31.0
> >
Mark Rutland May 24, 2021, 10:37 a.m. UTC | #3
On Mon, May 24, 2021 at 03:36:59PM +0800, Jisheng Zhang wrote:
> Fix below warning if KFENCE=y but RODATA_FULL=n:
> 
> [    0.000000] ------------[ cut here ]------------
> [    0.000000] WARNING: CPU: 0 PID: 0 at mm/memory.c:2462 apply_to_pmd_range+0xec/0x190
> [    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.13.0-rc1+ #10
> [    0.000000] Hardware name: linux,dummy-virt (DT)
> [    0.000000] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO BTYPE=--)
> [    0.000000] pc : apply_to_pmd_range+0xec/0x190
> [    0.000000] lr : __apply_to_page_range+0x94/0x170
> [    0.000000] sp : ffffffc010573e20
> [    0.000000] x29: ffffffc010573e20 x28: ffffff801f400000 x27: ffffff801f401000
> [    0.000000] x26: 0000000000000001 x25: ffffff801f400fff x24: ffffffc010573f28
> [    0.000000] x23: ffffffc01002b710 x22: ffffffc0105fa450 x21: ffffffc010573ee4
> [    0.000000] x20: ffffff801fffb7d0 x19: ffffff801f401000 x18: 00000000fffffffe
> [    0.000000] x17: 000000000000003f x16: 000000000000000a x15: ffffffc01060b940
> [    0.000000] x14: 0000000000000000 x13: 0098968000000000 x12: 0000000098968000
> [    0.000000] x11: 0000000000000000 x10: 0000000098968000 x9 : 0000000000000001
> [    0.000000] x8 : 0000000000000000 x7 : ffffffc010573ee4 x6 : 0000000000000001
> [    0.000000] x5 : ffffffc010573f28 x4 : ffffffc01002b710 x3 : 0000000040000000
> [    0.000000] x2 : ffffff801f5fffff x1 : 0000000000000001 x0 : 007800005f400705
> [    0.000000] Call trace:
> [    0.000000]  apply_to_pmd_range+0xec/0x190
> [    0.000000]  __apply_to_page_range+0x94/0x170
> [    0.000000]  apply_to_page_range+0x10/0x20
> [    0.000000]  __change_memory_common+0x50/0xdc
> [    0.000000]  set_memory_valid+0x30/0x40
> [    0.000000]  kfence_init_pool+0x9c/0x16c
> [    0.000000]  kfence_init+0x20/0x98
> [    0.000000]  start_kernel+0x284/0x3f8
> 
> Fixes: 840b23986344 ("arm64, kfence: enable KFENCE for ARM64")
> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

It would be good if the commit message could explain the problem more
thoroughly, e.g.

| When we added KFENCE support for arm64, we intended that it would
| force the entire linear map to be mapped at page granularity, but we
| only enforced this in arch_add_memory() and not in map_mem(), so
| memory mapped at boot time can be mapped at a larger granularity.
|
| When booting a kernel with KFENCE=y and RODATA_FULL=n, this results in
| the following WARNING at boot:
|
| < warning here >

With that:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
>  arch/arm64/mm/mmu.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 6dd9369e3ea0..89b66ef43a0f 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -515,7 +515,8 @@ static void __init map_mem(pgd_t *pgdp)
>  	 */
>  	BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end));
>  
> -	if (rodata_full || crash_mem_map || debug_pagealloc_enabled())
> +	if (rodata_full || crash_mem_map || debug_pagealloc_enabled() ||
> +	    IS_ENABLED(CONFIG_KFENCE))
>  		flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
>  
>  	/*
> -- 
> 2.31.0
>
Mark Rutland May 24, 2021, 11:13 a.m. UTC | #4
On Mon, May 24, 2021 at 12:43:56PM +0200, Marco Elver wrote:
> On Mon, 24 May 2021 at 12:37, Mark Rutland <mark.rutland@arm.com> wrote:
> >
> > On Mon, May 24, 2021 at 03:36:59PM +0800, Jisheng Zhang wrote:
> > > Fix below warning if KFENCE=y but RODATA_FULL=n:
> > >
> > > [    0.000000] ------------[ cut here ]------------
> > > [    0.000000] WARNING: CPU: 0 PID: 0 at mm/memory.c:2462 apply_to_pmd_range+0xec/0x190
> > > [    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.13.0-rc1+ #10
> > > [    0.000000] Hardware name: linux,dummy-virt (DT)
> > > [    0.000000] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO BTYPE=--)
> > > [    0.000000] pc : apply_to_pmd_range+0xec/0x190
> > > [    0.000000] lr : __apply_to_page_range+0x94/0x170
> > > [    0.000000] sp : ffffffc010573e20
> > > [    0.000000] x29: ffffffc010573e20 x28: ffffff801f400000 x27: ffffff801f401000
> > > [    0.000000] x26: 0000000000000001 x25: ffffff801f400fff x24: ffffffc010573f28
> > > [    0.000000] x23: ffffffc01002b710 x22: ffffffc0105fa450 x21: ffffffc010573ee4
> > > [    0.000000] x20: ffffff801fffb7d0 x19: ffffff801f401000 x18: 00000000fffffffe
> > > [    0.000000] x17: 000000000000003f x16: 000000000000000a x15: ffffffc01060b940
> > > [    0.000000] x14: 0000000000000000 x13: 0098968000000000 x12: 0000000098968000
> > > [    0.000000] x11: 0000000000000000 x10: 0000000098968000 x9 : 0000000000000001
> > > [    0.000000] x8 : 0000000000000000 x7 : ffffffc010573ee4 x6 : 0000000000000001
> > > [    0.000000] x5 : ffffffc010573f28 x4 : ffffffc01002b710 x3 : 0000000040000000
> > > [    0.000000] x2 : ffffff801f5fffff x1 : 0000000000000001 x0 : 007800005f400705
> > > [    0.000000] Call trace:
> > > [    0.000000]  apply_to_pmd_range+0xec/0x190
> > > [    0.000000]  __apply_to_page_range+0x94/0x170
> > > [    0.000000]  apply_to_page_range+0x10/0x20
> > > [    0.000000]  __change_memory_common+0x50/0xdc
> > > [    0.000000]  set_memory_valid+0x30/0x40
> > > [    0.000000]  kfence_init_pool+0x9c/0x16c
> > > [    0.000000]  kfence_init+0x20/0x98
> > > [    0.000000]  start_kernel+0x284/0x3f8
> > >
> > > Fixes: 840b23986344 ("arm64, kfence: enable KFENCE for ARM64")
> > > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> >
> > It would be good if the commit message could explain the problem more
> > thoroughly, e.g.
> >
> > | When we added KFENCE support for arm64, we intended that it would
> > | force the entire linear map to be mapped at page granularity, but we
> > | only enforced this in arch_add_memory() and not in map_mem(), so
> > | memory mapped at boot time can be mapped at a larger granularity.
> > |
> > | When booting a kernel with KFENCE=y and RODATA_FULL=n, this results in
> > | the following WARNING at boot:
> > |
> > | < warning here >
> >
> > With that:
> >
> > Acked-by: Mark Rutland <mark.rutland@arm.com>
> 
> We also need "Cc: stable@vger.kernel.org", right?

That would be a good idea, yes. I can't recall whether "Fixes" alone is
intended to be sufficient or not to trigger a backport.

Mark.

> Acked-by: Marco Elver <elver@google.com>
> 
> Thank you both!
> 
> -- Marco
diff mbox series

Patch

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 6dd9369e3ea0..89b66ef43a0f 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -515,7 +515,8 @@  static void __init map_mem(pgd_t *pgdp)
 	 */
 	BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end));
 
-	if (rodata_full || crash_mem_map || debug_pagealloc_enabled())
+	if (rodata_full || crash_mem_map || debug_pagealloc_enabled() ||
+	    IS_ENABLED(CONFIG_KFENCE))
 		flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 
 	/*