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* Merge tag 'mm-hotfixes-stable-2023-07-28-15-52' of ↵Linus Torvalds2023-07-295-10/+17
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull hotfixes from Andrew Morton: "11 hotfixes. Five are cc:stable and the remainder address post-6.4 issues or aren't considered serious enough to justify backporting" * tag 'mm-hotfixes-stable-2023-07-28-15-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mm/memory-failure: fix hardware poison check in unpoison_memory() proc/vmcore: fix signedness bug in read_from_oldmem() mailmap: update remaining active codeaurora.org email addresses mm: lock VMA in dup_anon_vma() before setting ->anon_vma mm: fix memory ordering for mm_lock_seq and vm_lock_seq scripts/spelling.txt: remove 'thead' as a typo mm/pagewalk: fix EFI_PGT_DUMP of espfix area shmem: minor fixes to splice-read implementation tmpfs: fix Documentation of noswap and huge mount options Revert "um: Use swap() to make code cleaner" mm/damon/core-test: initialise context before test in damon_test_set_attrs()
| * mm/memory-failure: fix hardware poison check in unpoison_memory()Sidhartha Kumar2023-07-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It was pointed out[1] that using folio_test_hwpoison() is wrong as we need to check the indiviual page that has poison. folio_test_hwpoison() only checks the head page so go back to using PageHWPoison(). User-visible effects include existing hwpoison-inject tests possibly failing as unpoisoning a single subpage could lead to unpoisoning an entire folio. Memory unpoisoning could also not work as expected as the function will break early due to only checking the head page and not the actually poisoned subpage. [1]: https://lore.kernel.org/lkml/ZLIbZygG7LqSI9xe@casper.infradead.org/ Link: https://lkml.kernel.org/r/20230717181812.167757-1-sidhartha.kumar@oracle.com Fixes: a6fddef49eef ("mm/memory-failure: convert unpoison_memory() to folios") Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm: lock VMA in dup_anon_vma() before setting ->anon_vmaJann Horn2023-07-271-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When VMAs are merged, dup_anon_vma() is called with `dst` pointing to the VMA that is being expanded to cover the area previously occupied by another VMA. This currently happens while `dst` is not write-locked. This means that, in the `src->anon_vma && !dst->anon_vma` case, as soon as the assignment `dst->anon_vma = src->anon_vma` has happened, concurrent page faults can happen on `dst` under the per-VMA lock. This is already icky in itself, since such page faults can now install pages into `dst` that are attached to an `anon_vma` that is not yet tied back to the `anon_vma` with an `anon_vma_chain`. But if `anon_vma_clone()` fails due to an out-of-memory error, things get much worse: `anon_vma_clone()` then reverts `dst->anon_vma` back to NULL, and `dst` remains completely unconnected to the `anon_vma`, even though we can have pages in the area covered by `dst` that point to the `anon_vma`. This means the `anon_vma` of such pages can be freed while the pages are still mapped into userspace, which leads to UAF when a helper like folio_lock_anon_vma_read() tries to look up the anon_vma of such a page. This theoretically is a security bug, but I believe it is really hard to actually trigger as an unprivileged user because it requires that you can make an order-0 GFP_KERNEL allocation fail, and the page allocator tries pretty hard to prevent that. I think doing the vma_start_write() call inside dup_anon_vma() is the most straightforward fix for now. For a kernel-assisted reproducer, see the notes section of the patch mail. Link: https://lkml.kernel.org/r/20230721034643.616851-1-jannh@google.com Fixes: 5e31275cc997 ("mm: add per-VMA lock and helper functions to control it") Signed-off-by: Jann Horn <jannh@google.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm/pagewalk: fix EFI_PGT_DUMP of espfix areaHugh Dickins2023-07-271-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Booting x86_64 with CONFIG_EFI_PGT_DUMP=y shows messages of the form "mm/pgtable-generic.c:53: bad pmd (____ptrval____)(8000000100077061)". EFI_PGT_DUMP dumps all of efi_mm, including the espfix area, which is set up with pmd entries which fit the pmd_bad() check: so 0d940a9b270b warns and clears those entries, which would ruin running Win16 binaries. The failing pte_offset_map() stopped such a kernel from even booting, until a few commits later be872f83bf57 changed the pagewalk to tolerate that: but it needs to be even more careful, to not spoil those entries. I might have preferred to change init_espfix_ap() not to use "bad" pmd entries; or to leave them out of the efi_mm dump. But there is great value in staying away from there, and a pagewalk check of address against TASK_SIZE may protect from other such aberrations too. Link: https://lkml.kernel.org/r/22bca736-4cab-9ee5-6a52-73a3b2bbe865@google.com Closes: https://lore.kernel.org/linux-mm/CABXGCsN3JqXckWO=V7p=FhPU1tK03RE1w9UE6xL5Y86SMk209w@mail.gmail.com/ Fixes: 0d940a9b270b ("mm/pgtable: allow pte_offset_map[_lock]() to fail") Fixes: be872f83bf57 ("mm/pagewalk: walk_pte_range() allow for pte_offset_map()") Signed-off-by: Hugh Dickins <hughd@google.com> Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Laura Abbott <labbott@fedoraproject.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * shmem: minor fixes to splice-read implementationHugh Dickins2023-07-271-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | HWPoison: my reading of folio_test_hwpoison() is that it only tests the head page of a large folio, whereas splice_folio_into_pipe() will splice as much of the folio as it can: so for safety we should also check the has_hwpoisoned flag, set if any of the folio's pages are hwpoisoned. (Perhaps that ugliness can be improved at the mm end later.) The call to splice_zeropage_into_pipe() risked overrunning past EOF: ask it for "part" not "len". Link: https://lkml.kernel.org/r/32c72c9c-72a8-115f-407d-f0148f368@google.com Fixes: bd194b187115 ("shmem: Implement splice-read") Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: David Howells <dhowells@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm/damon/core-test: initialise context before test in damon_test_set_attrs()Feng Tang2023-07-271-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Running kunit test for 6.5-rc1 hits one bug: ok 10 damon_test_update_monitoring_result general protection fault, probably for non-canonical address 0x1bffa5c419cfb81: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 110 Comm: kunit_try_catch Tainted: G N 6.5.0-rc2 #15 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:damon_set_attrs+0xb9/0x120 Code: f8 00 00 00 4c 8d 58 e0 48 39 c3 74 ba 41 ba 59 17 b7 d1 49 8b 43 10 4d 8d 4b 10 48 8d 70 e0 49 39 c1 74 50 49 8b 40 08 31 d2 <69> 4e 18 10 27 00 00 49 f7 30 31 d2 48 89 c5 89 c8 f7 f5 31 d2 89 RSP: 0000:ffffc900005bfd40 EFLAGS: 00010246 RAX: ffffffff81159fc0 RBX: ffffc900005bfeb8 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 01bffa5c419cfb69 RDI: ffffc900005bfd70 RBP: ffffc90000013c10 R08: ffffc900005bfdc0 R09: ffffffff81ff10ed R10: 00000000d1b71759 R11: ffffffff81ff10dd R12: ffffc90000013a78 R13: ffff88810eb78180 R14: ffffffff818297c0 R15: ffffc90000013c28 FS: 0000000000000000(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000002a1c001 CR4: 0000000000370ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> damon_test_set_attrs+0x63/0x1f0 kunit_generic_run_threadfn_adapter+0x17/0x30 kthread+0xfd/0x130 The problem seems to be related with the damon_ctx was used without being initialized. Fix it by adding the initialization. Link: https://lkml.kernel.org/r/20230718052811.1065173-1-feng.tang@intel.com Fixes: aa13779be6b7 ("mm/damon/core-test: add a test for damon_set_attrs()") Signed-off-by: Feng Tang <feng.tang@intel.com> Reviewed-by: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | Revert "mm,memblock: reset memblock.reserved to system init state to prevent ↵Mike Rapoport (IBM)2023-07-281-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | UAF" This reverts commit 9e46e4dcd9d6cd88342b028dbfa5f4fb7483d39c. kbuild reports a warning in memblock_remove_region() because of a false positive caused by partial reset of the memblock state. Doing the full reset will remove the false positives, but will allow late use of memblock_free() to go unnoticed, so it is better to revert the offending commit. WARNING: CPU: 0 PID: 1 at mm/memblock.c:352 memblock_remove_region (kbuild/src/x86_64/mm/memblock.c:352 (discriminator 1)) Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.5.0-rc3-00001-g9e46e4dcd9d6 #2 RIP: 0010:memblock_remove_region (kbuild/src/x86_64/mm/memblock.c:352 (discriminator 1)) Call Trace: memblock_discard (kbuild/src/x86_64/mm/memblock.c:383) page_alloc_init_late (kbuild/src/x86_64/include/linux/find.h:208 kbuild/src/x86_64/include/linux/nodemask.h:266 kbuild/src/x86_64/mm/mm_init.c:2405) kernel_init_freeable (kbuild/src/x86_64/init/main.c:1325 kbuild/src/x86_64/init/main.c:1546) kernel_init (kbuild/src/x86_64/init/main.c:1439) ret_from_fork (kbuild/src/x86_64/arch/x86/kernel/process.c:145) ret_from_fork_asm (kbuild/src/x86_64/arch/x86/entry/entry_64.S:298) Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202307271656.447aa17e-oliver.sang@intel.com Signed-off-by: "Mike Rapoport (IBM)" <rppt@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/mempolicy: Take VMA lock before replacing policyJann Horn2023-07-281-1/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | mbind() calls down into vma_replace_policy() without taking the per-VMA locks, replaces the VMA's vma->vm_policy pointer, and frees the old policy. That's bad; a concurrent page fault might still be using the old policy (in vma_alloc_folio()), resulting in use-after-free. Normally this will manifest as a use-after-free read first, but it can result in memory corruption, including because vma_alloc_folio() can call mpol_cond_put() on the freed policy, which conditionally changes the policy's refcount member. This bug is specific to CONFIG_NUMA, but it does also affect non-NUMA systems as long as the kernel was built with CONFIG_NUMA. Signed-off-by: Jann Horn <jannh@google.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Fixes: 5e31275cc997 ("mm: add per-VMA lock and helper functions to control it") Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge tag 'fixes-2023-07-27' of ↵Linus Torvalds2023-07-271-0/+4
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock Pull memblock fix from Mike Rapoport: "A call to memblock_free() or memblock_phys_free() issued after memblock data is discarded will result in use after free in memblock_isolate_range(). Avoid those issues by making sure that memblock_discard points memblock.reserved.regions back at the static buffer" * tag 'fixes-2023-07-27' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock: mm,memblock: reset memblock.reserved to system init state to prevent UAF
| * | mm,memblock: reset memblock.reserved to system init state to prevent UAFRik van Riel2023-07-241-0/+4
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The memblock_discard function frees the memblock.reserved.regions array, which is good. However, if a subsequent memblock_free (or memblock_phys_free) comes in later, from for example ima_free_kexec_buffer, that will result in a use after free bug in memblock_isolate_range. When running a kernel with CONFIG_KASAN enabled, this will cause a kernel panic very early in boot. Without CONFIG_KASAN, there is a chance that memblock_isolate_range might scribble on memory that is now in use by somebody else. Avoid those issues by making sure that memblock_discard points memblock.reserved.regions back at the static buffer. If memblock_free is called after memblock memory is discarded, that will print a warning in memblock_remove_region. Signed-off-by: Rik van Riel <riel@surriel.com> Link: https://lore.kernel.org/r/20230719154137.732d8525@imladris.surriel.com Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
* / mm: lock_vma_under_rcu() must check vma->anon_vma under vma lockJann Horn2023-07-271-12/+16
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | lock_vma_under_rcu() tries to guarantee that __anon_vma_prepare() can't be called in the VMA-locked page fault path by ensuring that vma->anon_vma is set. However, this check happens before the VMA is locked, which means a concurrent move_vma() can concurrently call unlink_anon_vmas(), which disassociates the VMA's anon_vma. This means we can get UAF in the following scenario: THREAD 1 THREAD 2 ======== ======== <page fault> lock_vma_under_rcu() rcu_read_lock() mas_walk() check vma->anon_vma mremap() syscall move_vma() vma_start_write() unlink_anon_vmas() <syscall end> handle_mm_fault() __handle_mm_fault() handle_pte_fault() do_pte_missing() do_anonymous_page() anon_vma_prepare() __anon_vma_prepare() find_mergeable_anon_vma() mas_walk() [looks up VMA X] munmap() syscall (deletes VMA X) reusable_anon_vma() [called on freed VMA X] This is a security bug if you can hit it, although an attacker would have to win two races at once where the first race window is only a few instructions wide. This patch is based on some previous discussion with Linus Torvalds on the security list. Cc: stable@vger.kernel.org Fixes: 5e31275cc997 ("mm: add per-VMA lock and helper functions to control it") Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/mlock: fix vma iterator conversion of apply_vma_lock_flags()Liam R. Howlett2023-07-171-4/+5
| | | | | | | | | | | | | | | | | | | | | | apply_vma_lock_flags() calls mlock_fixup(), which could merge the VMA after where the vma iterator is located. Although this is not an issue, the next iteration of the loop will check the start of the vma to be equal to the locally saved 'tmp' variable and cause an incorrect failure scenario. Fix the error by setting tmp to the end of the vma iterator value before restarting the loop. There is also a potential of the error code being overwritten when the loop terminates early. Fix the return issue by directly returning when an error is encountered since there is nothing to undo after the loop. Link: https://lkml.kernel.org/r/20230711175020.4091336-1-Liam.Howlett@oracle.com Fixes: 37598f5a9d8b ("mlock: convert mlock to vma iterator") Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reported-by: Ryan Roberts <ryan.roberts@arm.com> Link: https://lore.kernel.org/linux-mm/50341ca1-d582-b33a-e3d0-acb08a65166f@arm.com/ Tested-by: Ryan Roberts <ryan.roberts@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: lock newly mapped VMA with corrected orderingHugh Dickins2023-07-091-2/+2
| | | | | | | | | | | | | | | | Lockdep is certainly right to complain about (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_write+0x2d/0x3f but task is already holding lock: (&mapping->i_mmap_rwsem){+.+.}-{3:3}, at: mmap_region+0x4dc/0x6db Invert those to the usual ordering. Fixes: 33313a747e81 ("mm: lock newly mapped VMA which can be modified after it becomes visible") Cc: stable@vger.kernel.org Signed-off-by: Hugh Dickins <hughd@google.com> Tested-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'mm-hotfixes-stable-2023-07-08-10-43' of ↵Linus Torvalds2023-07-086-19/+34
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull hotfixes from Andrew Morton: "16 hotfixes. Six are cc:stable and the remainder address post-6.4 issues" The merge undoes the disabling of the CONFIG_PER_VMA_LOCK feature, since it was all hopefully fixed in mainline. * tag 'mm-hotfixes-stable-2023-07-08-10-43' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: lib: dhry: fix sleeping allocations inside non-preemptable section kasan, slub: fix HW_TAGS zeroing with slub_debug kasan: fix type cast in memory_is_poisoned_n mailmap: add entries for Heiko Stuebner mailmap: update manpage link bootmem: remove the vmemmap pages from kmemleak in free_bootmem_page MAINTAINERS: add linux-next info mailmap: add Markus Schneider-Pargmann writeback: account the number of pages written back mm: call arch_swap_restore() from do_swap_page() squashfs: fix cache race with migration mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison docs: update ocfs2-devel mailing list address MAINTAINERS: update ocfs2-devel mailing list address mm: disable CONFIG_PER_VMA_LOCK until its fixed fork: lock VMAs of the parent process when forking
| * kasan, slub: fix HW_TAGS zeroing with slub_debugAndrey Konovalov2023-07-082-14/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 946fa0dbf2d8 ("mm/slub: extend redzone check to extra allocated kmalloc space than requested") added precise kmalloc redzone poisoning to the slub_debug functionality. However, this commit didn't account for HW_TAGS KASAN fully initializing the object via its built-in memory initialization feature. Even though HW_TAGS KASAN memory initialization contains special memory initialization handling for when slub_debug is enabled, it does not account for in-object slub_debug redzones. As a result, HW_TAGS KASAN can overwrite these redzones and cause false-positive slub_debug reports. To fix the issue, avoid HW_TAGS KASAN memory initialization when slub_debug is enabled altogether. Implement this by moving the __slub_debug_enabled check to slab_post_alloc_hook. Common slab code seems like a more appropriate place for a slub_debug check anyway. Link: https://lkml.kernel.org/r/678ac92ab790dba9198f9ca14f405651b97c8502.1688561016.git.andreyknvl@google.com Fixes: 946fa0dbf2d8 ("mm/slub: extend redzone check to extra allocated kmalloc space than requested") Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reported-by: Will Deacon <will@kernel.org> Acked-by: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: kasan-dev@googlegroups.com Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Collingbourne <pcc@google.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * kasan: fix type cast in memory_is_poisoned_nAndrey Konovalov2023-07-081-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit bb6e04a173f0 ("kasan: use internal prototypes matching gcc-13 builtins") introduced a bug into the memory_is_poisoned_n implementation: it effectively removed the cast to a signed integer type after applying KASAN_GRANULE_MASK. As a result, KASAN started failing to properly check memset, memcpy, and other similar functions. Fix the bug by adding the cast back (through an additional signed integer variable to make the code more readable). Link: https://lkml.kernel.org/r/8c9e0251c2b8b81016255709d4ec42942dcaf018.1688431866.git.andreyknvl@google.com Fixes: bb6e04a173f0 ("kasan: use internal prototypes matching gcc-13 builtins") Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * writeback: account the number of pages written backMatthew Wilcox (Oracle)2023-07-081-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | nr_to_write is a count of pages, so we need to decrease it by the number of pages in the folio we just wrote, not by 1. Most callers specify either LONG_MAX or 1, so are unaffected, but writeback_sb_inodes() might end up writing 512x as many pages as it asked for. Dave added: : XFS is the only filesystem this would affect, right? AFAIA, nothing : else enables large folios and uses writeback through : write_cache_pages() at this point... : : In which case, I'd be surprised if much difference, if any, gets : noticed by anyone. Link: https://lkml.kernel.org/r/20230628185548.981888-1-willy@infradead.org Fixes: 793917d997df ("mm/readahead: Add large folio readahead") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm: call arch_swap_restore() from do_swap_page()Peter Collingbourne2023-07-081-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit c145e0b47c77 ("mm: streamline COW logic in do_swap_page()") moved the call to swap_free() before the call to set_pte_at(), which meant that the MTE tags could end up being freed before set_pte_at() had a chance to restore them. Fix it by adding a call to the arch_swap_restore() hook before the call to swap_free(). Link: https://lkml.kernel.org/r/20230523004312.1807357-2-pcc@google.com Link: https://linux-review.googlesource.com/id/I6470efa669e8bd2f841049b8c61020c510678965 Fixes: c145e0b47c77 ("mm: streamline COW logic in do_swap_page()") Signed-off-by: Peter Collingbourne <pcc@google.com> Reported-by: Qun-wei Lin <Qun-wei.Lin@mediatek.com> Closes: https://lore.kernel.org/all/5050805753ac469e8d727c797c2218a9d780d434.camel@mediatek.com/ Acked-by: David Hildenbrand <david@redhat.com> Acked-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Steven Price <steven.price@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: <stable@vger.kernel.org> [6.1+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparisonJohn Hubbard2023-07-081-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following crash happens for me when running the -mm selftests (below). Specifically, it happens while running the uffd-stress subtests: kernel BUG at mm/hugetlb.c:7249! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ #109 Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018 RIP: 0010:huge_pte_alloc+0x12c/0x1a0 ... Call Trace: <TASK> ? __die_body+0x63/0xb0 ? die+0x9f/0xc0 ? do_trap+0xab/0x180 ? huge_pte_alloc+0x12c/0x1a0 ? do_error_trap+0xc6/0x110 ? huge_pte_alloc+0x12c/0x1a0 ? handle_invalid_op+0x2c/0x40 ? huge_pte_alloc+0x12c/0x1a0 ? exc_invalid_op+0x33/0x50 ? asm_exc_invalid_op+0x16/0x20 ? __pfx_put_prev_task_idle+0x10/0x10 ? huge_pte_alloc+0x12c/0x1a0 hugetlb_fault+0x1a3/0x1120 ? finish_task_switch+0xb3/0x2a0 ? lock_is_held_type+0xdb/0x150 handle_mm_fault+0xb8a/0xd40 ? find_vma+0x5d/0xa0 do_user_addr_fault+0x257/0x5d0 exc_page_fault+0x7b/0x1f0 asm_exc_page_fault+0x22/0x30 That happens because a BUG() statement in huge_pte_alloc() attempts to check that a pte, if present, is a hugetlb pte, but it does so in a non-lockless-safe manner that leads to a false BUG() report. We got here due to a couple of bugs, each of which by itself was not quite enough to cause a problem: First of all, before commit c33c794828f2("mm: ptep_get() conversion"), the BUG() statement in huge_pte_alloc() was itself fragile: it relied upon compiler behavior to only read the pte once, despite using it twice in the same conditional. Next, commit c33c794828f2 ("mm: ptep_get() conversion") broke that delicate situation, by causing all direct pte reads to be done via READ_ONCE(). And so READ_ONCE() got called twice within the same BUG() conditional, leading to comparing (potentially, occasionally) different versions of the pte, and thus to false BUG() reports. Fix this by taking a single snapshot of the pte before using it in the BUG conditional. Now, that commit is only partially to blame here but, people doing bisections will invariably land there, so this will help them find a fix for a real crash. And also, the previous behavior was unlikely to ever expose this bug--it was fragile, yet not actually broken. So that's why I chose this commit for the Fixes tag, rather than the commit that created the original BUG() statement. Link: https://lkml.kernel.org/r/20230701010442.2041858-1-jhubbard@nvidia.com Fixes: c33c794828f2 ("mm: ptep_get() conversion") Signed-off-by: John Hubbard <jhubbard@nvidia.com> Acked-by: James Houghton <jthoughton@google.com> Acked-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Acked-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alex Williamson <alex.williamson@redhat.com> Cc: Alexander Potapenko <glider@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Dave Airlie <airlied@gmail.com> Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ian Rogers <irogers@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: SeongJae Park <sj@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm: disable CONFIG_PER_VMA_LOCK until its fixedSuren Baghdasaryan2023-07-081-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A memory corruption was reported in [1] with bisection pointing to the patch [2] enabling per-VMA locks for x86. Disable per-VMA locks config to prevent this issue until the fix is confirmed. This is expected to be a temporary measure. [1] https://bugzilla.kernel.org/show_bug.cgi?id=217624 [2] https://lore.kernel.org/all/20230227173632.3292573-30-surenb@google.com Link: https://lkml.kernel.org/r/20230706011400.2949242-3-surenb@google.com Reported-by: Jiri Slaby <jirislaby@kernel.org> Closes: https://lore.kernel.org/all/dbdef34c-3a07-5951-e1ae-e9c6e3cdf51b@kernel.org/ Reported-by: Jacob Young <jacobly.alt@gmail.com> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217624 Fixes: 0bff0aaea03e ("x86/mm: try VMA lock-based page fault handling first") Signed-off-by: Suren Baghdasaryan <surenb@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Holger Hoffstätte <holger@applied-asynchrony.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | mm: lock newly mapped VMA which can be modified after it becomes visibleSuren Baghdasaryan2023-07-081-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | mmap_region adds a newly created VMA into VMA tree and might modify it afterwards before dropping the mmap_lock. This poses a problem for page faults handled under per-VMA locks because they don't take the mmap_lock and can stumble on this VMA while it's still being modified. Currently this does not pose a problem since post-addition modifications are done only for file-backed VMAs, which are not handled under per-VMA lock. However, once support for handling file-backed page faults with per-VMA locks is added, this will become a race. Fix this by write-locking the VMA before inserting it into the VMA tree. Other places where a new VMA is added into VMA tree do not modify it after the insertion, so do not need the same locking. Cc: stable@vger.kernel.org Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: lock a vma before stack expansionSuren Baghdasaryan2023-07-081-0/+4
| | | | | | | | | | | | | | | | | | | | | | With recent changes necessitating mmap_lock to be held for write while expanding a stack, per-VMA locks should follow the same rules and be write-locked to prevent page faults into the VMA being expanded. Add the necessary locking. Cc: stable@vger.kernel.org Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | gup: make the stack expansion warning a bit more targetedLinus Torvalds2023-07-051-10/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I added a warning about about GUP no longer expanding the stack in commit a425ac5365f6 ("gup: add warning if some caller would seem to want stack expansion"), but didn't really expect anybody to hit it. And it's true that nobody seems to have hit a _real_ case yet, but we certainly have a number of reports of false positives. Which not only causes extra noise in itself, but might also end up hiding any real cases if they do exist. So let's tighten up the warning condition, and replace the simplistic vma = find_vma(mm, start); if (vma && (start < vma->vm_start)) { WARN_ON_ONCE(vma->vm_flags & VM_GROWSDOWN); with a vma = gup_vma_lookup(mm, start); helper function which works otherwise like just "vma_lookup()", but with some heuristics for when to warn about gup no longer causing stack expansion. In particular, don't just warn for "below the stack", but warn if it's _just_ below the stack (with "just below" arbitrarily defined as 64kB, because why not?). And rate-limit it to at most once per hour, which means that any false positives shouldn't completely hide subsequent reports, but we won't be flooding the logs about it either. The previous code triggered when some GUP user (chromium crashpad) accessing past the end of the previous vma, for example. That has never expanded the stack, it just causes GUP to return early, and as such we shouldn't be warning about it. This is still going trigger the randomized testers, but to mitigate the noise from that, use "dump_stack()" instead of "WARN_ON_ONCE()" to get the kernel call chain. We'll get the relevant information, but syzbot shouldn't get too upset about it. Also, don't even bother with the GROWSUP case, which would be using different heuristics entirely, but only happens on parisc. Reported-by: kernel test robot <oliver.sang@intel.com> Reported-by: John Hubbard <jhubbard@nvidia.com> Reported-by: syzbot+6cf44e127903fdf9d929@syzkaller.appspotmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: don't do validate_mm() unnecessarily and without mmap lockingLinus Torvalds2023-07-041-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is an addition to commit ae80b4041984 ("mm: validate the mm before dropping the mmap lock"), because it turns out there were two problems, but lockdep just stopped complaining after finding the first one. The do_vmi_align_munmap() function now drops the mmap lock after doing the validate_mm() call, but it turns out that one of the callers then immediately calls validate_mm() again. That's both a bit silly, and now (again) happens without the mmap lock held. So just remove that validate_mm() call from the caller, but make sure to not lose any coverage by doing that mm sanity checking in the error path of do_vmi_align_munmap() too. Reported-and-tested-by: kernel test robot <oliver.sang@intel.com> Link: https://lore.kernel.org/lkml/ZKN6CdkKyxBShPHi@xsang-OptiPlex-9020/ Fixes: 408579cd627a ("mm: Update do_vmi_align_munmap() return semantics") Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: validate the mm before dropping the mmap lockLinus Torvalds2023-07-031-2/+1
|/ | | | | | | | | | | | | | | | Commit 408579cd627a ("mm: Update do_vmi_align_munmap() return semantics") made the return value and locking semantics of do_vmi_align_munmap() more straightforward, but in the process it ended up unlocking the mmap lock just a tad too early: the debug code doing the mmap layout validation still needs to run with the lock held, or things might change under it while it's trying to validate things. So just move the unlocking to after the validate_mm() call. Reported-by: kernel test robot <oliver.sang@intel.com> Link: https://lore.kernel.org/lkml/ZKIsoMOT71uwCIZX@xsang-OptiPlex-9020/ Fixes: 408579cd627a ("mm: Update do_vmi_align_munmap() return semantics") Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: Update do_vmi_align_munmap() return semanticsLiam R. Howlett2023-07-012-67/+55
| | | | | | | | | | | | | | | | | | | | | | Since do_vmi_align_munmap() will always honor the downgrade request on the success, the callers no longer have to deal with confusing return codes. Since all callers that request downgrade actually want the lock to be dropped, change the downgrade to an unlock request. Note that the lock still needs to be held in read mode during the page table clean up to avoid races with a map request. Update do_vmi_align_munmap() to return 0 for success. Clean up the callers and comments to always expect the unlock to be honored on the success path. The error path will always leave the lock untouched. As part of the cleanup, the wrapper function do_vmi_munmap() and callers to the wrapper are also updated. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/linux-mm/20230629191414.1215929-1-willy@infradead.org/ Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: Always downgrade mmap_lock if requestedMatthew Wilcox (Oracle)2023-07-011-13/+2
| | | | | | | | | Now that stack growth must always hold the mmap_lock for write, we can always downgrade the mmap_lock to read and safely unmap pages from the page table, even if we're next to a stack. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* xtensa: fix lock_mm_and_find_vma in case VMA not foundMax Filippov2023-07-011-1/+6
| | | | | | | | | | MMU version of lock_mm_and_find_vma releases the mm lock before returning when VMA is not found. Do the same in noMMU version. This fixes hang on an attempt to handle protection fault. Fixes: d85a143b69ab ("xtensa: fix NOMMU build with lock_mm_and_find_vma() conversion") Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* xtensa: fix NOMMU build with lock_mm_and_find_vma() conversionLinus Torvalds2023-07-011-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It turns out that xtensa has a really odd configuration situation: you can do a no-MMU config, but still have the page fault code enabled. Which doesn't sound all that sensible, but it turns out that xtensa can have protection faults even without the MMU, and we have this: config PFAULT bool "Handle protection faults" if EXPERT && !MMU default y help Handle protection faults. MMU configurations must enable it. noMMU configurations may disable it if used memory map never generates protection faults or faults are always fatal. If unsure, say Y. which completely violated my expectations of the page fault handling. End result: Guenter reports that the xtensa no-MMU builds all fail with arch/xtensa/mm/fault.c: In function ‘do_page_fault’: arch/xtensa/mm/fault.c:133:8: error: implicit declaration of function ‘lock_mm_and_find_vma’ because I never exposed the new lock_mm_and_find_vma() function for the no-MMU case. Doing so is simple enough, and fixes the problem. Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net> Fixes: a050ba1e7422 ("mm/fault: convert remaining simple cases to lock_mm_and_find_vma()") Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'memblock-v6.5-rc1' of ↵Linus Torvalds2023-06-301-5/+29
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock Pull memblock updates from Mike Rapoport: - add test for memblock_alloc_node() - minor coding style fixes - add flags and nid info in memblock debugfs * tag 'memblock-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock: memblock: Update nid info in memblock debugfs memblock: Add flags and nid info in memblock debugfs Fix some coding style errors in memblock.c Add tests for memblock_alloc_node()
| * memblock: Update nid info in memblock debugfsYuwei Guan2023-06-021-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | The node id for memblock reserved regions will be wrong, so let's show 'x' for reg->nid == MAX_NUMNODES in debugfs to keep it align. Suggested-by: Mike Rapoport (IBM) <rppt@kernel.org> Co-developed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Yuwei Guan <ssawgyw@gmail.com> Link: https://lore.kernel.org/r/20230601133149.37160-1-ssawgyw@gmail.com Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
| * memblock: Add flags and nid info in memblock debugfsYuwei Guan2023-05-241-2/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the memblock debugfs can display the count of memblock_type and the base and end of the reg. However, when memblock_mark_*() or memblock_set_node() is executed on some range, the information in the existing debugfs cannot make it clear why the address is not consecutive. For example, cat /sys/kernel/debug/memblock/memory 0: 0x0000000080000000..0x00000000901fffff 1: 0x0000000090200000..0x00000000905fffff 2: 0x0000000090600000..0x0000000092ffffff 3: 0x0000000093000000..0x00000000973fffff 4: 0x0000000097400000..0x00000000b71fffff 5: 0x00000000c0000000..0x00000000dfffffff 6: 0x00000000e2500000..0x00000000f87fffff 7: 0x00000000f8800000..0x00000000fa7fffff 8: 0x00000000fa800000..0x00000000fd3effff 9: 0x00000000fd3f0000..0x00000000fd3fefff 10: 0x00000000fd3ff000..0x00000000fd7fffff 11: 0x00000000fd800000..0x00000000fd901fff 12: 0x00000000fd902000..0x00000000fd909fff 13: 0x00000000fd90a000..0x00000000fd90bfff 14: 0x00000000fd90c000..0x00000000ffffffff 15: 0x0000000880000000..0x0000000affffffff So we can add flags and nid to this debugfs. For example, cat /sys/kernel/debug/memblock/memory 0: 0x0000000080000000..0x00000000901fffff 0 NONE 1: 0x0000000090200000..0x00000000905fffff 0 NOMAP 2: 0x0000000090600000..0x0000000092ffffff 0 NONE 3: 0x0000000093000000..0x00000000973fffff 0 NOMAP 4: 0x0000000097400000..0x00000000b71fffff 0 NONE 5: 0x00000000c0000000..0x00000000dfffffff 0 NONE 6: 0x00000000e2500000..0x00000000f87fffff 0 NONE 7: 0x00000000f8800000..0x00000000fa7fffff 0 NOMAP 8: 0x00000000fa800000..0x00000000fd3effff 0 NONE 9: 0x00000000fd3f0000..0x00000000fd3fefff 0 NOMAP 10: 0x00000000fd3ff000..0x00000000fd7fffff 0 NONE 11: 0x00000000fd800000..0x00000000fd901fff 0 NOMAP 12: 0x00000000fd902000..0x00000000fd909fff 0 NONE 13: 0x00000000fd90a000..0x00000000fd90bfff 0 NOMAP 14: 0x00000000fd90c000..0x00000000ffffffff 0 NONE 15: 0x0000000880000000..0x0000000affffffff 0 NONE Signed-off-by: Yuwei Guan <ssawgyw@gmail.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Link: https://lore.kernel.org/r/20230519105321.333-1-ssawgyw@gmail.com Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
| * Fix some coding style errors in memblock.cClaudio Migliorelli2023-05-241-3/+3
| | | | | | | | | | | | | | | | | | | | This patch removes the initialization of some static variables to 0 and `false` in the memblock source file, according to the coding style guidelines. Signed-off-by: Claudio Migliorelli <claudio.migliorelli@mail.polimi.it> Link: https://lore.kernel.org/r/87r0sa7mm8.fsf@mail.polimi.it Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
* | Merge tag 'unmap-fix-20230629' of git://git.infradead.org/users/dwmw2/linuxLinus Torvalds2023-06-301-4/+5
|\ \ | | | | | | | | | | | | | | | | | | | | | Pull mm fix from David Woodhouse: "Fix error return from do_vmi_align_munmap()" * tag 'unmap-fix-20230629' of git://git.infradead.org/users/dwmw2/linux: mm/mmap: Fix error return in do_vmi_align_munmap()
| * | mm/mmap: Fix error return in do_vmi_align_munmap()David Woodhouse2023-06-281-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If mas_store_gfp() in the gather loop failed, the 'error' variable that ultimately gets returned was not being set. In many cases, its original value of -ENOMEM was still in place, and that was fine. But if VMAs had been split at the start or end of the range, then 'error' could be zero. Change to the 'error = foo(); if (error) goto …' idiom to fix the bug. Also clean up a later case which avoided the same bug by *explicitly* setting error = -ENOMEM right before calling the function that might return -ENOMEM. In a final cosmetic change, move the 'Point of no return' comment to *after* the goto. That's been in the wrong place since the preallocation was removed, and this new error path was added. Fixes: 606c812eb1d5 ("mm/mmap: Fix error path in do_vmi_align_munmap()") Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Cc: stable@vger.kernel.org Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
* | | Merge tag 'slab-for-6.5' of ↵Linus Torvalds2023-06-306-93/+62
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab Pull slab updates from Vlastimil Babka: - SLAB deprecation: Following the discussion at LSF/MM 2023 [1] and no objections, the SLAB allocator is deprecated by renaming the config option (to make its users notice) to CONFIG_SLAB_DEPRECATED with updated help text. SLUB should be used instead. Existing defconfigs with CONFIG_SLAB are also updated. - SLAB_NO_MERGE kmem_cache flag (Jesper Dangaard Brouer): There are (very limited) cases where kmem_cache merging is undesirable, and existing ways to prevent it are hacky. Introduce a new flag to do that cleanly and convert the existing hacky users. Btrfs plans to use this for debug kernel builds (that use case is always fine), networking for performance reasons (that should be very rare). - Replace the usage of weak PRNGs (David Keisar Schmidt): In addition to using stronger RNGs for the security related features, the code is a bit cleaner. - Misc code cleanups (SeongJae Parki, Xiongwei Song, Zhen Lei, and zhaoxinchao) Link: https://lwn.net/Articles/932201/ [1] * tag 'slab-for-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: mm/slab_common: use SLAB_NO_MERGE instead of negative refcount mm/slab: break up RCU readers on SLAB_TYPESAFE_BY_RCU example code mm/slab: add a missing semicolon on SLAB_TYPESAFE_BY_RCU example code mm/slab_common: reduce an if statement in create_cache() mm/slab: introduce kmem_cache flag SLAB_NO_MERGE mm/slab: rename CONFIG_SLAB to CONFIG_SLAB_DEPRECATED mm/slab: remove HAVE_HARDENED_USERCOPY_ALLOCATOR mm/slab_common: Replace invocation of weak PRNG mm/slab: Replace invocation of weak PRNG slub: Don't read nr_slabs and total_objects directly slub: Remove slabs_node() function slub: Remove CONFIG_SMP defined check slub: Put objects_show() into CONFIG_SLUB_DEBUG enabled block slub: Correct the error code when slab_kset is NULL mm/slab: correct return values in comment for _kmem_cache_create()
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| *---. \ \ Merge branches 'slab/for-6.5/prandom', 'slab/for-6.5/slab_no_merge' and ↵Vlastimil Babka2023-06-165-43/+39
| |\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'slab/for-6.5/slab-deprecate' into slab/for-next Merge the feature branches scheduled for 6.5: - replace the usage of weak PRNGs, by David Keisar Schmidt - introduce the SLAB_NO_MERGE kmem_cache flag, by Jesper Dangaard Brouer - deprecate CONFIG_SLAB, with a planned removal, by myself
| | | | * | | mm/slab: rename CONFIG_SLAB to CONFIG_SLAB_DEPRECATEDVlastimil Babka2023-05-261-2/+14
| | | | | |/ | | | | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As discussed at LSF/MM [1] [2] and with no objections raised there, deprecate the SLAB allocator. Rename the user-visible option so that users with CONFIG_SLAB=y get a new prompt with explanation during make oldconfig, while make olddefconfig will just switch to SLUB. In all defconfigs with CONFIG_SLAB=y remove the line so those also switch to SLUB. Regressions due to the switch should be reported to linux-mm and slab maintainers. [1] https://lore.kernel.org/all/4b9fc9c6-b48c-198f-5f80-811a44737e5f@suse.cz/ [2] https://lwn.net/Articles/932201/ Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k Acked-by: Helge Deller <deller@gmx.de> # parisc
| | | * | | mm/slab_common: use SLAB_NO_MERGE instead of negative refcountVlastimil Babka2023-06-161-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When CONFIG_MEMCG_KMEM is enabled, we disable cache merging for KMALLOC_NORMAL caches so they don't end up merged with a cache that uses ad-hoc __GFP_ACCOUNT when allocating. This was implemented by setting the refcount to -1, but now we have a proper SLAB_NO_MERGE flag, so use that instead. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Rientjes <rientjes@google.com>
| | | * | | mm/slab: introduce kmem_cache flag SLAB_NO_MERGEJesper Dangaard Brouer2023-06-023-7/+7
| | | |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow API users of kmem_cache_create to specify that they don't want any slab merge or aliasing (with similar sized objects). Use this in kfence_test. The SKB (sk_buff) kmem_cache slab is critical for network performance. Network stack uses kmem_cache_{alloc,free}_bulk APIs to gain performance by amortising the alloc/free cost. For the bulk API to perform efficiently the slub fragmentation need to be low. Especially for the SLUB allocator, the efficiency of bulk free API depend on objects belonging to the same slab (page). When running different network performance microbenchmarks, I started to notice that performance was reduced (slightly) when machines had longer uptimes. I believe the cause was 'skbuff_head_cache' got aliased/merged into the general slub for 256 bytes sized objects (with my kernel config, without CONFIG_HARDENED_USERCOPY). For SKB kmem_cache network stack have reasons for not merging, but it varies depending on kernel config (e.g. CONFIG_HARDENED_USERCOPY). We want to explicitly set SLAB_NO_MERGE for this kmem_cache. Another use case for the flag has been described by David Sterba [1]: > This can be used for more fine grained control over the caches or for > debugging builds where separate slabs can verify that no objects leak. > The slab_nomerge boot option is too coarse and would need to be > enabled on all testing hosts. There are some other ways how to disable > merging, e.g. a slab constructor but this disables poisoning besides > that it adds additional overhead. Other flags are internal and may > have other semantics. > A concrete example what motivates the flag. During 'btrfs balance' > slab top reported huge increase in caches like > 1330095 1330095 100% 0.10K 34105 39 136420K Acpi-ParseExt > 1734684 1734684 100% 0.14K 61953 28 247812K pid_namespace > 8244036 6873075 83% 0.11K 229001 36 916004K khugepaged_mm_slot > which was confusing and that it's because of slab merging was not the > first idea. After rebooting with slab_nomerge all the caches were > from btrfs_ namespace as expected. [1] https://lore.kernel.org/all/20230524101748.30714-1-dsterba@suse.com/ [ vbabka@suse.cz: rename to SLAB_NO_MERGE, change the flag value to the one proposed by David so it does not collide with internal SLAB/SLUB flags, write a comment for the flag, expand changelog, drop the skbuff part to be handled spearately ] Link: https://lore.kernel.org/all/167396280045.539803.7540459812377220500.stgit@firesoul/ Reported-by: David Sterba <dsterba@suse.com> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
| | * | | mm/slab_common: Replace invocation of weak PRNGDavid Keisar Schmidt2023-05-221-8/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Slab allocator randomization inside slab_common.c uses the prandom_u32 PRNG. That was added to prevent attackers to obtain information on the heap state. However, this PRNG turned out to be weak, as noted in commit c51f8f88d705 To fix it, we have changed the invocation of prandom_u32_state to get_random_u32 to ensure the PRNG is strong. Since a modulo operation is applied right after that, in the Fisher-Yates shuffle, we used get_random_u32_below, to achieve uniformity. Signed-off-by: David Keisar Schmidt <david.keisarschm@mail.huji.ac.il> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
| | * | | mm/slab: Replace invocation of weak PRNGDavid Keisar Schmidt2023-05-221-20/+9
| | |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Slab allocator randomization uses the prandom_u32 PRNG. That was added to prevent attackers to obtain information on the heap state, by randomizing the freelists state. However, this PRNG turned out to be weak, as noted in commit c51f8f88d705 To fix it, we have changed the invocation of prandom_u32_state to get_random_u32 to ensure the PRNG is strong. Since a modulo operation is applied right after that, we used get_random_u32_below, to achieve uniformity. In addition, we changed the freelist_init_state union to struct, since the rnd_state inside which is used to store the state of prandom_u32, is not needed anymore, since get_random_u32 maintains its own state. Signed-off-by: David Keisar Schmidt <david.keisarschm@mail.huji.ac.il> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
| * | | mm/slab_common: reduce an if statement in create_cache()Zhen Lei2023-06-061-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the 'out:' statement block out of the successful path to avoid redundant check on 'err'. The value of 'err' is always zero on success and negative on failure. No functional changes, no performance improvements, just a little more readability. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
| * | | mm/slab: remove HAVE_HARDENED_USERCOPY_ALLOCATORVlastimil Babka2023-05-242-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With SLOB removed, both remaining allocators support hardened usercopy, so remove the config and associated #ifdef. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
| * | | slub: Don't read nr_slabs and total_objects directlyXiongwei Song2023-05-221-7/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have node_nr_slabs() to read nr_slabs, node_nr_objs() to read total_objects in a kmem_cache_node, so no need to access the two members directly. Signed-off-by: Xiongwei Song <xiongwei.song@windriver.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
| * | | slub: Remove slabs_node() functionXiongwei Song2023-05-221-13/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When traversing nodes one by one, the get_node() function called in for_each_kmem_cache_node macro, no need to call get_node() again in slabs_node(), just reading nr_slabs field should be enough. However, the node_nr_slabs() function can do this. Hence, the slabs_node() function is not needed anymore. Signed-off-by: Xiongwei Song <xiongwei.song@windriver.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
| * | | slub: Remove CONFIG_SMP defined checkXiongwei Song2023-05-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As CONFIG_SMP is one of dependencies of CONFIG_SLUB_CPU_PARTIAL, so if CONFIG_SLUB_CPU_PARTIAL is defined then CONFIG_SMP must be defined, no need to check CONFIG_SMP definition here. Signed-off-by: Xiongwei Song <xiongwei.song@windriver.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
| * | | slub: Put objects_show() into CONFIG_SLUB_DEBUG enabled blockXiongwei Song2023-05-221-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The SO_ALL|SO_OBJECTS pair is only used when enabling CONFIG_SLUB_DEBUG option, so the objects_show() definition should be surrounded by CONFIG_SLUB_DEBUG too. Signed-off-by: Xiongwei Song <xiongwei.song@windriver.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
| * | | slub: Correct the error code when slab_kset is NULLXiongwei Song2023-05-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The -ENOSYS is inproper when kset_create_and_add call returns a NULL pointer, the failure more likely is because lacking memory, hence returning -ENOMEM is better. Signed-off-by: Xiongwei Song <xiongwei.song@windriver.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
| * | | mm/slab: correct return values in comment for _kmem_cache_create()zhaoxinchao2023-05-221-6/+2
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | __kmem_cache_create() returns 0 on success and non-zero on failure. The comment is wrong in two instances, so fix the first one and remove the second one. Also make the comment non-doc, because it doesn't describe an API function, but SLAB-specific implementation. Signed-off-by: zhaoxinchao <chrisxinchao@outlook.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
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