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mm: Preserve _PAGE_DEVMAP across mprotect() calls

PATCH In review Jan Kara 4 participants 5 messages Oct 9, 2018 – Oct 10, 2018

Subsystems (6)
Stable branch Memory management x86 VFS +2 more subsystems
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Jan Kara

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#0 lore raw

PATCH 1/1 mm: Preserve _PAGE_DEVMAP across mprotect() calls

Currently _PAGE_DEVMAP bit is not preserved in mprotect(2) calls. As a result we will see warnings such as:

BUG: Bad page map in process JobWrk0013  pte:800001803875ea25 pmd:7624381067
addr:00007f0930720000 vm_flags:280000f9 anon_vma:          (null) mapping:ffff97f2384056f0 index:0
file:457-000000fe00000030-00000009-000000ca-00000001_2001.fileblock fault:xfs_filemap_fault [xfs] mmap:xfs_file_mmap [xfs] readpage:          (null)
CPU: 3 PID: 15848 Comm: JobWrk0013 Tainted: G        W          4.12.14-2.g7573215-default #1 SLE12-SP4 (unreleased)
Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.01.00.0833.051120182255 05/11/2018
Call Trace:
 dump_stack+0x5a/0x75
 print_bad_pte+0x217/0x2c0
 ? enqueue_task_fair+0x76/0x9f0
 _vm_normal_page+0xe5/0x100
 zap_pte_range+0x148/0x740
 unmap_page_range+0x39a/0x4b0
 unmap_vmas+0x42/0x90
 unmap_region+0x99/0xf0
 ? vma_gap_callbacks_rotate+0x1a/0x20
 do_munmap+0x255/0x3a0
 vm_munmap+0x54/0x80
 SyS_munmap+0x1d/0x30
 do_syscall_64+0x74/0x150
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2

...

when mprotect(2) gets used on DAX mappings. Also there is a wide variety of other failures that can result from the missing _PAGE_DEVMAP flag when the area gets used by get_user_pages() later.

Fix the problem by including _PAGE_DEVMAP in a set of flags that get preserved by mprotect(2).

Fixes 69660fd797c3 ("x86, mm: introduce _PAGE_DEVMAP")
Fixes ebd31197931d ("powerpc/mm: Add devmap support for ppc64")
CC [email protected]
Signed-off-by Jan Kara <[email protected]>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 4 ++--
 arch/x86/include/asm/pgtable_types.h         | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)
arch/powerpc/include/asm/book3s/64/pgtable.h +2 -2
index 2fdc865ca374..2a2486526d1f 100644
@@ -114,7 +114,7 @@
  */
 #define _HPAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
 			 _PAGE_ACCESSED | H_PAGE_THP_HUGE | _PAGE_PTE | \
-			 _PAGE_SOFT_DIRTY)
+			 _PAGE_SOFT_DIRTY | _PAGE_DEVMAP)
 /*
  * user access blocked by key
  */

@@ -132,7 +132,7 @@
  */
 #define _PAGE_CHG_MASK	(PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
 			 _PAGE_ACCESSED | _PAGE_SPECIAL | _PAGE_PTE |	\
-			 _PAGE_SOFT_DIRTY)
+			 _PAGE_SOFT_DIRTY | _PAGE_DEVMAP)
 
 #define H_PTE_PKEY  (H_PTE_PKEY_BIT0 | H_PTE_PKEY_BIT1 | H_PTE_PKEY_BIT2 | \
 		     H_PTE_PKEY_BIT3 | H_PTE_PKEY_BIT4)
arch/x86/include/asm/pgtable_types.h +1 -1
index b64acb08a62b..106b7d0e2dae 100644
@@ -124,7 +124,7 @@
  */
 #define _PAGE_CHG_MASK	(PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT |		\
 			 _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY |	\
-			 _PAGE_SOFT_DIRTY)
+			 _PAGE_SOFT_DIRTY | _PAGE_DEVMAP)
 #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE)
 
 /*
Signature · 1 line
2.16.4
Acked-by on v1 1/1
#1 lore raw
Quoted 29 lines · Jan Kara

Currently _PAGE_DEVMAP bit is not preserved in mprotect(2) calls. As a result we will see warnings such as:

BUG: Bad page map in process JobWrk0013  pte:800001803875ea25 pmd:7624381067
addr:00007f0930720000 vm_flags:280000f9 anon_vma:          (null) mapping:ffff97f2384056f0 index:0
file:457-000000fe00000030-00000009-000000ca-00000001_2001.fileblock fault:xfs_filemap_fault [xfs] mmap:xfs_file_mmap [xfs] readpage:          (null)
CPU: 3 PID: 15848 Comm: JobWrk0013 Tainted: G        W          4.12.14-2.g7573215-default #1 SLE12-SP4 (unreleased)
Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.01.00.0833.051120182255 05/11/2018
Call Trace:
 dump_stack+0x5a/0x75
 print_bad_pte+0x217/0x2c0
 ? enqueue_task_fair+0x76/0x9f0
 _vm_normal_page+0xe5/0x100
 zap_pte_range+0x148/0x740
 unmap_page_range+0x39a/0x4b0
 unmap_vmas+0x42/0x90
 unmap_region+0x99/0xf0
 ? vma_gap_callbacks_rotate+0x1a/0x20
 do_munmap+0x255/0x3a0
 vm_munmap+0x54/0x80
 SyS_munmap+0x1d/0x30
 do_syscall_64+0x74/0x150
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2

...

when mprotect(2) gets used on DAX mappings. Also there is a wide variety of other failures that can result from the missing _PAGE_DEVMAP flag when the area gets used by get_user_pages() later.

Quoted 7 lines

Fix the problem by including _PAGE_DEVMAP in a set of flags that get preserved by mprotect(2).

Fixes 69660fd797c3 ("x86, mm: introduce _PAGE_DEVMAP")
Fixes ebd31197931d ("powerpc/mm: Add devmap support for ppc64")
CC [email protected]
Signed-off-by Jan Kara <[email protected]>
Acked-by Michal Hocko <[email protected]>
Quoted 42 lines
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 4 ++--
 arch/x86/include/asm/pgtable_types.h         | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)
arch/powerpc/include/asm/book3s/64/pgtable.h +2 -2
index 2fdc865ca374..2a2486526d1f 100644
@@ -114,7 +114,7 @@
  */
 #define _HPAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
 			 _PAGE_ACCESSED | H_PAGE_THP_HUGE | _PAGE_PTE | \
-			 _PAGE_SOFT_DIRTY)
+			 _PAGE_SOFT_DIRTY | _PAGE_DEVMAP)
 /*
  * user access blocked by key
  */

@@ -132,7 +132,7 @@
  */
 #define _PAGE_CHG_MASK	(PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
 			 _PAGE_ACCESSED | _PAGE_SPECIAL | _PAGE_PTE |	\
-			 _PAGE_SOFT_DIRTY)
+			 _PAGE_SOFT_DIRTY | _PAGE_DEVMAP)
 
 #define H_PTE_PKEY  (H_PTE_PKEY_BIT0 | H_PTE_PKEY_BIT1 | H_PTE_PKEY_BIT2 | \
 		     H_PTE_PKEY_BIT3 | H_PTE_PKEY_BIT4)
arch/x86/include/asm/pgtable_types.h +1 -1
index b64acb08a62b..106b7d0e2dae 100644
@@ -124,7 +124,7 @@
  */
 #define _PAGE_CHG_MASK	(PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT |		\
 			 _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY |	\
-			 _PAGE_SOFT_DIRTY)
+			 _PAGE_SOFT_DIRTY | _PAGE_DEVMAP)
 #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE)
 
 /*
Signature · 1 line
2.16.4
Signature · 2 lines
Michal Hocko
SUSE Labs
#2 lore raw
In reply to Jan Kara
Quoted 30 lines · Jan Kara

Currently _PAGE_DEVMAP bit is not preserved in mprotect(2) calls. As a result we will see warnings such as:

BUG: Bad page map in process JobWrk0013  pte:800001803875ea25 pmd:7624381067
addr:00007f0930720000 vm_flags:280000f9 anon_vma:          (null) mapping:ffff97f2384056f0 index:0
file:457-000000fe00000030-00000009-000000ca-00000001_2001.fileblock fault:xfs_filemap_fault [xfs] mmap:xfs_file_mmap [xfs] readpage:          (null)
CPU: 3 PID: 15848 Comm: JobWrk0013 Tainted: G        W          4.12.14-2.g7573215-default #1 SLE12-SP4 (unreleased)
Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.01.00.0833.051120182255 05/11/2018
Call Trace:
 dump_stack+0x5a/0x75
 print_bad_pte+0x217/0x2c0
 ? enqueue_task_fair+0x76/0x9f0
 _vm_normal_page+0xe5/0x100
 zap_pte_range+0x148/0x740
 unmap_page_range+0x39a/0x4b0
 unmap_vmas+0x42/0x90
 unmap_region+0x99/0xf0
 ? vma_gap_callbacks_rotate+0x1a/0x20
 do_munmap+0x255/0x3a0
 vm_munmap+0x54/0x80
 SyS_munmap+0x1d/0x30
 do_syscall_64+0x74/0x150
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2

...

when mprotect(2) gets used on DAX mappings. Also there is a wide variety of other failures that can result from the missing _PAGE_DEVMAP flag when the area gets used by get_user_pages() later.

Quoted 7 lines

Fix the problem by including _PAGE_DEVMAP in a set of flags that get preserved by mprotect(2).

Fixes 69660fd797c3 ("x86, mm: introduce _PAGE_DEVMAP")
Fixes ebd31197931d ("powerpc/mm: Add devmap support for ppc64")
CC [email protected]
Signed-off-by Jan Kara <[email protected]>

Looks good, do you want me to take this upstream along with the livelock fix?

author reviewer
#3 lore raw
Quoted 34 lines · Dan Williams
Quoted 33 lines · Jan Kara

Currently _PAGE_DEVMAP bit is not preserved in mprotect(2) calls. As a result we will see warnings such as:

BUG: Bad page map in process JobWrk0013  pte:800001803875ea25 pmd:7624381067
addr:00007f0930720000 vm_flags:280000f9 anon_vma:          (null) mapping:ffff97f2384056f0 index:0
file:457-000000fe00000030-00000009-000000ca-00000001_2001.fileblock fault:xfs_filemap_fault [xfs] mmap:xfs_file_mmap [xfs] readpage:          (null)
CPU: 3 PID: 15848 Comm: JobWrk0013 Tainted: G        W          4.12.14-2.g7573215-default #1 SLE12-SP4 (unreleased)
Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.01.00.0833.051120182255 05/11/2018
Call Trace:
 dump_stack+0x5a/0x75
 print_bad_pte+0x217/0x2c0
 ? enqueue_task_fair+0x76/0x9f0
 _vm_normal_page+0xe5/0x100
 zap_pte_range+0x148/0x740
 unmap_page_range+0x39a/0x4b0
 unmap_vmas+0x42/0x90
 unmap_region+0x99/0xf0
 ? vma_gap_callbacks_rotate+0x1a/0x20
 do_munmap+0x255/0x3a0
 vm_munmap+0x54/0x80
 SyS_munmap+0x1d/0x30
 do_syscall_64+0x74/0x150
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2

...

when mprotect(2) gets used on DAX mappings. Also there is a wide variety of other failures that can result from the missing _PAGE_DEVMAP flag when the area gets used by get_user_pages() later.

Fix the problem by including _PAGE_DEVMAP in a set of flags that get preserved by mprotect(2).

Quoted 6 lines
Quoted 4 lines
Fixes 69660fd797c3 ("x86, mm: introduce _PAGE_DEVMAP")
Fixes ebd31197931d ("powerpc/mm: Add devmap support for ppc64")
CC [email protected]
Signed-off-by Jan Kara <[email protected]>

Looks good, do you want me to take this upstream along with the livelock fix?

Yes, I think that would be best. Thanks!

Honza

Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR