kernel/git/stable/linux-stable.git/mm/memory.c, branch linux-5.8.y

mm: track page table modifications in __apply_to_page_range()

2020-09-09T17:14:32+00:00

commit e80d3909be42f7e38cc350c1ba109cf0aa51956a upstream. __apply_to_page_range() is also used to change and/or allocate page-table pages in the vmalloc area of the address space. Make sure these changes get synchronized to other page-tables in the system by calling arch_sync_kernel_mappings() when necessary. The impact appears limited to x86-32, where apply_to_page_range may miss updating the PMD. That leads to explosions in drivers like BUG: unable to handle page fault for address: fe036000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page *pde = 00000000 Oops: 0002 [#1] SMP CPU: 3 PID: 1300 Comm: gem_concurrent_ Not tainted 5.9.0-rc1+ #16 Hardware name: /NUC6i3SYB, BIOS SYSKLi35.86A.0024.2015.1027.2142 10/27/2015 EIP: __execlists_context_alloc+0x132/0x2d0 [i915] Code: 31 d2 89 f0 e8 2f 55 02 00 89 45 e8 3d 00 f0 ff ff 0f 87 11 01 00 00 8b 4d e8 03 4b 30 b8 5a 5a 5a 5a ba 01 00 00 00 8d 79 04 01 5a 5a 5a 5a c7 81 fc 0f 00 00 5a 5a 5a 5a 83 e7 fc 29 f9 81 EAX: 5a5a5a5a EBX: f60ca000 ECX: fe036000 EDX: 00000001 ESI: f43b7340 EDI: fe036004 EBP: f6389cb8 ESP: f6389c9c DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010286 CR0: 80050033 CR2: fe036000 CR3: 2d361000 CR4: 001506d0 DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 DR6: fffe0ff0 DR7: 00000400 Call Trace: execlists_context_alloc+0x10/0x20 [i915] intel_context_alloc_state+0x3f/0x70 [i915] __intel_context_do_pin+0x117/0x170 [i915] i915_gem_do_execbuffer+0xcc7/0x2500 [i915] i915_gem_execbuffer2_ioctl+0xcd/0x1f0 [i915] drm_ioctl_kernel+0x8f/0xd0 drm_ioctl+0x223/0x3d0 __ia32_sys_ioctl+0x1ab/0x760 __do_fast_syscall_32+0x3f/0x70 do_fast_syscall_32+0x29/0x60 do_SYSENTER_32+0x15/0x20 entry_SYSENTER_32+0x9f/0xf2 EIP: 0xb7f28559 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d 76 00 58 b8 77 00 00 00 cd 80 90 8d 76 EAX: ffffffda EBX: 00000005 ECX: c0406469 EDX: bf95556c ESI: b7e68000 EDI: c0406469 EBP: 00000005 ESP: bf9554d8 DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000296 Modules linked in: i915 x86_pkg_temp_thermal intel_powerclamp crc32_pclmul crc32c_intel intel_cstate intel_uncore intel_gtt drm_kms_helper intel_pch_thermal video button autofs4 i2c_i801 i2c_smbus fan CR2: 00000000fe036000 It looks like kasan, xen and i915 are vulnerable. Actual impact is "on thinkpad X60 in 5.9-rc1, screen starts blinking after 30-or-so minutes, and machine is unusable" [sfr@canb.auug.org.au: ARCH_PAGE_TABLE_SYNC_MASK needs vmalloc.h] Link: https://lkml.kernel.org/r/20200825172508.16800a4f@canb.auug.org.au [chris@chris-wilson.co.uk: changelog addition] [pavel@ucw.cz: changelog addition] Fixes: 2ba3e6947aed ("mm/vmalloc: track which page-table levels were modified") Fixes: 86cf69f1d893 ("x86/mm/32: implement arch_sync_kernel_mappings()") Signed-off-by: Joerg Roedel Signed-off-by: Stephen Rothwell Signed-off-by: Andrew Morton Tested-by: Chris Wilson [x86-32] Tested-by: Pavel Machek Acked-by: Linus Torvalds Cc: [5.8+] Link: https://lkml.kernel.org/r/20200821123746.16904-1-joro@8bytes.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/memory.c: skip spurious TLB flush for retried page fault

2020-08-26T09:49:02+00:00

commit b7333b58f358f38d90d78e00c1ee5dec82df10ad upstream. Recently we found regression when running will_it_scale/page_fault3 test on ARM64. Over 70% down for the multi processes cases and over 20% down for the multi threads cases. It turns out the regression is caused by commit 89b15332af7c ("mm: drop mmap_sem before calling balance_dirty_pages() in write fault"). The test mmaps a memory size file then write to the mapping, this would make all memory dirty and trigger dirty pages throttle, that upstream commit would release mmap_sem then retry the page fault. The retried page fault would see correct PTEs installed then just fall through to spurious TLB flush. The regression is caused by the excessive spurious TLB flush. It is fine on x86 since x86's spurious TLB flush is no-op. We could just skip the spurious TLB flush to mitigate the regression. Suggested-by: Linus Torvalds Reported-by: Xu Yu Debugged-by: Xu Yu Tested-by: Xu Yu Cc: Johannes Weiner Cc: Catalin Marinas Cc: Will Deacon Cc: Signed-off-by: Yang Shi Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: initialize return of vm_insert_pages

2020-07-24T19:42:41+00:00

clang static analysis reports a garbage return In file included from mm/memory.c:84: mm/memory.c:1612:2: warning: Undefined or garbage value returned to caller [core.uninitialized.UndefReturn] return err; ^~~~~~~~~~ The setting of err depends on a loop executing. So initialize err. Signed-off-by: Tom Rix Signed-off-by: Andrew Morton Link: http://lkml.kernel.org/r/20200703155354.29132-1-trix@redhat.com Signed-off-by: Linus Torvalds

mm/memory: fix IO cost for anonymous page

2020-06-26T07:27:38+00:00

With synchronous IO swap device, swap-in is directly handled in fault code. Since IO cost notation isn't added there, with synchronous IO swap device, LRU balancing could be wrongly biased. Fix it to count it in fault code. Link: http://lkml.kernel.org/r/1592288204-27734-4-git-send-email-iamjoonsoo.kim@lge.com Fixes: 314b57fb0460001 ("mm: balance LRU lists based on relative thrashing cache sizing") Signed-off-by: Joonsoo Kim Acked-by: Johannes Weiner Cc: Joonsoo Kim Cc: Michal Hocko Cc: Minchan Kim Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory.c: properly pte_offset_map_lock/unlock in vm_insert_pages()

2020-06-26T07:27:37+00:00

Calls to pte_offset_map() in vm_insert_pages() are erroneously not matched with a call to pte_unmap(). This would cause problems on architectures where that is not a no-op. This patch does away with the non-traditional locking in the existing code, and instead uses pte_offset_map_lock/unlock() as usual, incrementing PTE as necessary. The PTE pointer is kept within bounds since we clamp it with PTRS_PER_PTE. Link: http://lkml.kernel.org/r/20200618220446.20284-1-arjunroy.kdev@gmail.com Fixes: 8cd3984d81d5 ("mm/memory.c: add vm_insert_pages()") Signed-off-by: Arjun Roy Acked-by: David Rientjes Cc: Eric Dumazet Cc: Hugh Dickins Cc: Soheil Hassas Yeganeh Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: do_swap_page(): fix up the error code

2020-06-26T07:27:36+00:00

do_swap_page() returns error codes from the VM_FAULT* space. try_charge() might return -ENOMEM, though, and then do_swap_page() simply returns 0 which means a success. We almost never return ENOMEM for GFP_KERNEL single page charge. Except for async OOM handling (oom_disabled v1). So this needs translation to VM_FAULT_OOM otherwise the the page fault path will not notify the userspace and wait for an action. Link: http://lkml.kernel.org/r/20200617090238.GL9499@dhcp22.suse.cz Fixes: 4c6355b25e8b ("mm: memcontrol: charge swapin pages on instantiation") Signed-off-by: Michal Hocko Acked-by: Johannes Weiner Cc: Alex Shi Cc: Joonsoo Kim Cc: Shakeel Butt Cc: Hugh Dickins Cc: "Kirill A. Shutemov" Cc: Roman Gushchin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mmap locking API: convert mmap_sem comments

2020-06-09T16:39:14+00:00

Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka Reviewed-by: Daniel Jordan Cc: Davidlohr Bueso Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Laurent Dufour Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds

mmap locking API: convert mmap_sem API comments

2020-06-09T16:39:14+00:00

Convert comments that reference old mmap_sem APIs to reference corresponding new mmap locking APIs instead. Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka Reviewed-by: Davidlohr Bueso Reviewed-by: Daniel Jordan Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Laurent Dufour Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-12-walken@google.com Signed-off-by: Linus Torvalds

mmap locking API: rename mmap_sem to mmap_lock

2020-06-09T16:39:14+00:00

Rename the mmap_sem field to mmap_lock. Any new uses of this lock should now go through the new mmap locking api. The mmap_lock is still implemented as a rwsem, though this could change in the future. [akpm@linux-foundation.org: fix it for mm-gup-might_lock_readmmap_sem-in-get_user_pages_fast.patch] Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka Reviewed-by: Davidlohr Bueso Reviewed-by: Daniel Jordan Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Laurent Dufour Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-11-walken@google.com Signed-off-by: Linus Torvalds

mmap locking API: add mmap_assert_locked() and mmap_assert_write_locked()

2020-06-09T16:39:14+00:00

Add new APIs to assert that mmap_sem is held. Using this instead of rwsem_is_locked and lockdep_assert_held[_write] makes the assertions more tolerant of future changes to the lock type. Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka Reviewed-by: Daniel Jordan Cc: Davidlohr Bueso Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Laurent Dufour Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-10-walken@google.com Signed-off-by: Linus Torvalds