Skip to contentSkip to conversation

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

PATCH Superseded Jisheng Zhang 3 participants 6 messages May 24, 2021 arm64

v1 of 2 Superseded Latest is v2 →

lore
Share & tools
lore

Jisheng Zhang

author
#0 lore raw

PATCH 1/1 arm64: mm: don't use CON and BLK mapping if KFENCE is enabled

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 <[email protected]>
---
 arch/arm64/mm/mmu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
arch/arm64/mm/mmu.c +2 -1
index 6dd9369e3ea0..89b66ef43a0f 100644
@@ -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;
 
 	/*
Signature · 1 line
2.31.0
#1 lore raw
Quoted 3 lines · Jisheng Zhang

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" ?

Quoted 51 lines
[    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 <[email protected]>
---
 arch/arm64/mm/mmu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
arch/arm64/mm/mmu.c +2 -2
index 6dd9369e3ea0..89b66ef43a0f 100644
@@ -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

author
#2 lore raw
Quoted 9 lines · On Mon, 24 May 2021 12:05:21 +0200 Marco Elver wrote:
Quoted 3 lines · Jisheng Zhang

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

Quoted 52 lines
Quoted 52 lines
[    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 <[email protected]>
---
 arch/arm64/mm/mmu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
arch/arm64/mm/mmu.c +2 -2
index 6dd9369e3ea0..89b66ef43a0f 100644
@@ -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

reviewer Acked-by on v1 1/1
#3 lore raw
In reply to Jisheng Zhang
Quoted 30 lines · Jisheng Zhang

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
Quoted 2 lines
Fixes 840b23986344 ("arm64, kfence: enable KFENCE for ARM64")
Signed-off-by Jisheng Zhang <[email protected]>

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 <[email protected]>

Mark.

Quoted 21 lines
---
 arch/arm64/mm/mmu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
arch/arm64/mm/mmu.c +2 -1
index 6dd9369e3ea0..89b66ef43a0f 100644
@@ -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;
 
 	/*
Signature · 1 line
2.31.0
Acked-by
#4 lore raw
Quoted 48 lines · Mark Rutland
Quoted 30 lines · Jisheng Zhang

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
Quoted 2 lines
Fixes 840b23986344 ("arm64, kfence: enable KFENCE for ARM64")
Signed-off-by Jisheng Zhang <[email protected]>

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 >
Quoted 3 lines

With that:

Acked-by Mark Rutland <[email protected]>

We also need "Cc: [email protected]", right?

Acked-by Marco Elver <[email protected]>

Thank you both!

-- Marco

reviewer
#5 lore raw
Quoted 49 lines · Marco Elver
Quoted 48 lines · Mark Rutland
Quoted 30 lines · Jisheng Zhang

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
Quoted 2 lines
Fixes 840b23986344 ("arm64, kfence: enable KFENCE for ARM64")
Signed-off-by Jisheng Zhang <[email protected]>

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 >
Quoted 5 lines
Quoted 3 lines

With that:

Acked-by Mark Rutland <[email protected]>

We also need "Cc: [email protected]", 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.

Quoted 5 lines
Acked-by Marco Elver <[email protected]>

Thank you both!

-- Marco