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2022-11-30mm: use kstrtobool() instead of strtobool()Christophe JAILLET1-1/+2
strtobool() is the same as kstrtobool(). However, the latter is more used within the kernel. In order to remove strtobool() and slightly simplify kstrtox.h, switch to the other function name. While at it, include the corresponding header file (<linux/kstrtox.h>) Link: https://lkml.kernel.org/r/03f9401a6c8b87a1c786a2138d16b048f8d0eb53.1667336095.git.christophe.jaillet@wanadoo.fr Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Acked-by: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-03mm/page_table_check: fix typosChih-En Lin1-2/+2
Link: https://lkml.kernel.org/r/20220916090434.701194-1-shiyn.lin@gmail.com Signed-off-by: Chih-En Lin <shiyn.lin@gmail.com> Acked-by: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-11mm: fix use-after free of page_ext after race with memory-offlineCharan Teja Kalla1-3/+7
The below is one path where race between page_ext and offline of the respective memory blocks will cause use-after-free on the access of page_ext structure. process1 process2 --------- --------- a)doing /proc/page_owner doing memory offline through offline_pages. b) PageBuddy check is failed thus proceed to get the page_owner information through page_ext access. page_ext = lookup_page_ext(page); migrate_pages(); ................. Since all pages are successfully migrated as part of the offline operation,send MEM_OFFLINE notification where for page_ext it calls: offline_page_ext()--> __free_page_ext()--> free_page_ext()--> vfree(ms->page_ext) mem_section->page_ext = NULL c) Check for the PAGE_EXT flags in the page_ext->flags access results into the use-after-free (leading to the translation faults). As mentioned above, there is really no synchronization between page_ext access and its freeing in the memory_offline. The memory offline steps(roughly) on a memory block is as below: 1) Isolate all the pages 2) while(1) try free the pages to buddy.(->free_list[MIGRATE_ISOLATE]) 3) delete the pages from this buddy list. 4) Then free page_ext.(Note: The struct page is still alive as it is freed only during hot remove of the memory which frees the memmap, which steps the user might not perform). This design leads to the state where struct page is alive but the struct page_ext is freed, where the later is ideally part of the former which just representing the page_flags (check [3] for why this design is chosen). The abovementioned race is just one example __but the problem persists in the other paths too involving page_ext->flags access(eg: page_is_idle())__. Fix all the paths where offline races with page_ext access by maintaining synchronization with rcu lock and is achieved in 3 steps: 1) Invalidate all the page_ext's of the sections of a memory block by storing a flag in the LSB of mem_section->page_ext. 2) Wait until all the existing readers to finish working with the ->page_ext's with synchronize_rcu(). Any parallel process that starts after this call will not get page_ext, through lookup_page_ext(), for the block parallel offline operation is being performed. 3) Now safely free all sections ->page_ext's of the block on which offline operation is being performed. Note: If synchronize_rcu() takes time then optimizations can be done in this path through call_rcu()[2]. Thanks to David Hildenbrand for his views/suggestions on the initial discussion[1] and Pavan kondeti for various inputs on this patch. [1] https://lore.kernel.org/linux-mm/59edde13-4167-8550-86f0-11fc67882107@quicinc.com/ [2] https://lore.kernel.org/all/a26ce299-aed1-b8ad-711e-a49e82bdd180@quicinc.com/T/#u [3] https://lore.kernel.org/all/6fa6b7aa-731e-891c-3efb-a03d6a700efa@redhat.com/ [quic_charante@quicinc.com: rename label `loop' to `ext_put_continue' per David] Link: https://lkml.kernel.org/r/1661496993-11473-1-git-send-email-quic_charante@quicinc.com Link: https://lkml.kernel.org/r/1660830600-9068-1-git-send-email-quic_charante@quicinc.com Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com> Suggested-by: David Hildenbrand <david@redhat.com> Suggested-by: Michal Hocko <mhocko@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Fernand Sieber <sieberf@amazon.com> Cc: Minchan Kim <minchan@google.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Pavan Kondeti <quic_pkondeti@quicinc.com> Cc: SeongJae Park <sjpark@amazon.de> Cc: Shakeel Butt <shakeelb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: William Kucharski <william.kucharski@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-27Merge tag 'mm-hotfixes-stable-2022-05-27' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull hotfixes from Andrew Morton: "Six hotfixes. The page_table_check one from Miaohe Lin is considered a minor thing so it isn't marked for -stable. The remainder address pre-5.19 issues and are cc:stable" * tag 'mm-hotfixes-stable-2022-05-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mm/page_table_check: fix accessing unmapped ptep kexec_file: drop weak attribute from arch_kexec_apply_relocations[_add] mm/page_alloc: always attempt to allocate at least one page during bulk allocation hugetlb: fix huge_pmd_unshare address update zsmalloc: fix races between asynchronous zspage free and page migration Revert "mm/cma.c: remove redundant cma_mutex lock"
2022-05-27mm/page_table_check: fix accessing unmapped ptepMiaohe Lin1-1/+1
ptep is unmapped too early, so ptep could theoretically be accessed while it's unmapped. This might become a problem if/when CONFIG_HIGHPTE becomes available on riscv. Fix it by deferring pte_unmap() until page table checking is done. [akpm@linux-foundation.org: account for ptep alteration, per Matthew] Link: https://lkml.kernel.org/r/20220526113350.30806-1-linmiaohe@huawei.com Fixes: 80110bbfbba6 ("mm/page_table_check: check entries at pmd levels") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13mm: page_table_check: move pxx_user_accessible_page into x86Kefeng Wang1-17/+0
The pxx_user_accessible_page() checks the PTE bit, it's architecture-specific code, move them into x86's pgtable.h. These helpers are being moved out to make the page table check framework platform independent. Link: https://lkml.kernel.org/r/20220507110114.4128854-3-tongtiangen@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Tong Tiangen <tongtiangen@huawei.com> Acked-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13mm: page_table_check: using PxD_SIZE instead of PxD_PAGE_SIZETong Tiangen1-4/+4
Patch series "mm: page_table_check: add support on arm64 and riscv", v7. Page table check performs extra verifications at the time when new pages become accessible from the userspace by getting their page table entries (PTEs PMDs etc.) added into the table. It is supported on X86[1]. This patchset made some simple changes and make it easier to support new architecture, then we support this feature on ARM64 and RISCV. [1]https://lore.kernel.org/lkml/20211123214814.3756047-1-pasha.tatashin@soleen.com/ This patch (of 6): Compared with PxD_PAGE_SIZE, which is defined and used only on X86, PxD_SIZE is more common in each architecture. Therefore, it is more reasonable to use PxD_SIZE instead of PxD_PAGE_SIZE in page_table_check.c. At the same time, it is easier to support page table check in other architectures. The substitution has no functional impact on the x86. Link: https://lkml.kernel.org/r/20220507110114.4128854-1-tongtiangen@huawei.com Link: https://lkml.kernel.org/r/20220507110114.4128854-2-tongtiangen@huawei.com Signed-off-by: Tong Tiangen <tongtiangen@huawei.com> Suggested-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-03-22mm/page_table_check.c: use strtobool for param parsingDr. David Alan Gilbert1-9/+1
Use strtobool rather than open coding "on" and "off" parsing. Link: https://lkml.kernel.org/r/20220227181038.126926-1-linux@treblig.org Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-02-04mm/page_table_check: check entries at pmd levelsPasha Tatashin1-0/+20
syzbot detected a case where the page table counters were not properly updated. syzkaller login: ------------[ cut here ]------------ kernel BUG at mm/page_table_check.c:162! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 3099 Comm: pasha Not tainted 5.16.0+ #48 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIO4 RIP: 0010:__page_table_check_zero+0x159/0x1a0 Call Trace: free_pcp_prepare+0x3be/0xaa0 free_unref_page+0x1c/0x650 free_compound_page+0xec/0x130 free_transhuge_page+0x1be/0x260 __put_compound_page+0x90/0xd0 release_pages+0x54c/0x1060 __pagevec_release+0x7c/0x110 shmem_undo_range+0x85e/0x1250 ... The repro involved having a huge page that is split due to uprobe event temporarily replacing one of the pages in the huge page. Later the huge page was combined again, but the counters were off, as the PTE level was not properly updated. Make sure that when PMD is cleared and prior to freeing the level the PTEs are updated. Link: https://lkml.kernel.org/r/20220131203249.2832273-5-pasha.tatashin@soleen.com Fixes: df4e817b7108 ("mm: page table check") Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Greg Thelen <gthelen@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Paul Turner <pjt@google.com> Cc: Wei Xu <weixugc@google.com> Cc: Will Deacon <will@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-02-04mm/page_table_check: use unsigned long for page counters and cleanupPasha Tatashin1-28/+7
For consistency, use "unsigned long" for all page counters. Also, reduce code duplication by calling __page_table_check_*_clear() from __page_table_check_*_set() functions. Link: https://lkml.kernel.org/r/20220131203249.2832273-3-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Wei Xu <weixugc@google.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Greg Thelen <gthelen@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Paul Turner <pjt@google.com> Cc: Will Deacon <will@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-15mm: page table checkPasha Tatashin1-0/+270
Check user page table entries at the time they are added and removed. Allows to synchronously catch memory corruption issues related to double mapping. When a pte for an anonymous page is added into page table, we verify that this pte does not already point to a file backed page, and vice versa if this is a file backed page that is being added we verify that this page does not have an anonymous mapping We also enforce that read-only sharing for anonymous pages is allowed (i.e. cow after fork). All other sharing must be for file pages. Page table check allows to protect and debug cases where "struct page" metadata became corrupted for some reason. For example, when refcnt or mapcount become invalid. Link: https://lkml.kernel.org/r/20211221154650.1047963-4-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wei Xu <weixugc@google.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>