| Age | Commit message (Collapse) | Author | Files | Lines | |
|---|---|---|---|---|---|
| 2022-02-04 | mm/page_table_check: check entries at pmd levels | Pasha Tatashin | 1 | -0/+19 | |
| 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/[email protected] Fixes: df4e817b7108 ("mm: page table check") Signed-off-by: Pasha Tatashin <[email protected]> Acked-by: David Rientjes <[email protected]> Cc: Aneesh Kumar K.V <[email protected]> Cc: Anshuman Khandual <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Greg Thelen <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jiri Slaby <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Muchun Song <[email protected]> Cc: Paul Turner <[email protected]> Cc: Wei Xu <[email protected]> Cc: Will Deacon <[email protected]> Cc: Zi Yan <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> | |||||
| 2022-01-15 | mm: page table check | Pasha Tatashin | 1 | -0/+147 | |
| 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/[email protected] Signed-off-by: Pasha Tatashin <[email protected]> Cc: Aneesh Kumar K.V <[email protected]> Cc: Dave Hansen <[email protected]> Cc: David Rientjes <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Greg Thelen <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jiri Slaby <[email protected]> Cc: Jonathan Corbet <[email protected]> Cc: Kees Cook <[email protected]> Cc: Masahiro Yamada <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Muchun Song <[email protected]> Cc: Paul Turner <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Sami Tolvanen <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Wei Xu <[email protected]> Cc: Will Deacon <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> | |||||