Hi all, As proposed [1] by Peter Zijlstra below, this patch series aims to move pagetable_*_dtor() into __tlb_remove_table(). This will cleanup pagetable_*_dtor() a bit and more gracefully fix the UAF issue [2] reported by syzbot. ``` Notably: - s390 pud isn't calling the existing pagetable_pud_[cd]tor() - none of the p4d things have pagetable_p4d_[cd]tor() (x86,arm64,s390,riscv) and they have inconsistent accounting - while much of the _ctor calls are in generic code, many of the _dtor calls are in arch code for hysterial raisins, this could easily be fixed - if we fix ptlock_free() to handle NULL, then all the _dtor() functions can use it, and we can observe they're all identical and can be folded after all that cleanup, you can move the _dtor from *_free_tlb() into tlb_remove_table() -- which for the above case, would then have it called from __tlb_remove_table_free(). ``` And hi Andrew, I developed the code based on the latest linux-next, so I reverted the "mm: pgtable: make ptlock be freed by RCU" first. Once the review of this patch series is completed, the "mm: pgtable: make ptlock be freed by RCU" can be dropped directly from mm tree, and this revert patch will not be needed. This series is based on next-20241213. And I tested this patch series on x86 and only cross-compiled it on arm[64], powerpc, riscv, s390 and sparc. Comments and suggestions are welcome! Thanks, Qi [1]. https://lore.kernel.org/all/20241211133433.GC12500@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ [2]. https://lore.kernel.org/all/67548279.050a0220.a30f1.015b.GAE@xxxxxxxxxx/ Qi Zheng (12): Revert "mm: pgtable: make ptlock be freed by RCU" mm: pgtable: introduce generic p4d_alloc_one() and p4d_free() arm64: pgtable: use mmu gather to free p4d level page table s390: pgtable: add statistics for PUD and P4D level page table mm: pgtable: introduce pagetable_dtor() arm: pgtable: move pagetable_dtor() to __tlb_remove_table() arm64: pgtable: move pagetable_dtor() to __tlb_remove_table() riscv: pgtable: move pagetable_dtor() to __tlb_remove_table() x86: pgtable: move pagetable_dtor() to __tlb_remove_table() s390: pgtable: also move pagetable_dtor() of PxD to __tlb_remove_table() mm: pgtable: introduce generic __tlb_remove_table() mm: pgtable: move __tlb_remove_table_one() in x86 to generic file Documentation/mm/split_page_table_lock.rst | 4 +- arch/arm/include/asm/tlb.h | 10 ---- arch/arm64/include/asm/pgalloc.h | 17 +++--- arch/arm64/include/asm/tlb.h | 21 +++++--- arch/csky/include/asm/pgalloc.h | 2 +- arch/hexagon/include/asm/pgalloc.h | 2 +- arch/loongarch/include/asm/pgalloc.h | 2 +- arch/m68k/include/asm/mcf_pgalloc.h | 4 +- arch/m68k/include/asm/sun3_pgalloc.h | 2 +- arch/m68k/mm/motorola.c | 2 +- arch/mips/include/asm/pgalloc.h | 2 +- arch/nios2/include/asm/pgalloc.h | 2 +- arch/openrisc/include/asm/pgalloc.h | 2 +- arch/powerpc/include/asm/tlb.h | 1 + arch/powerpc/mm/book3s64/mmu_context.c | 2 +- arch/powerpc/mm/book3s64/pgtable.c | 2 +- arch/powerpc/mm/pgtable-frag.c | 4 +- arch/riscv/include/asm/pgalloc.h | 51 ++++++++---------- arch/riscv/include/asm/tlb.h | 18 ------- arch/riscv/mm/init.c | 4 +- arch/s390/include/asm/pgalloc.h | 31 +++++++---- arch/s390/include/asm/tlb.h | 37 ++++++------- arch/s390/mm/pgalloc.c | 21 ++------ arch/sh/include/asm/pgalloc.h | 2 +- arch/sparc/include/asm/tlb_32.h | 1 + arch/sparc/include/asm/tlb_64.h | 1 + arch/sparc/mm/init_64.c | 2 +- arch/sparc/mm/srmmu.c | 2 +- arch/um/include/asm/pgalloc.h | 6 +-- arch/x86/include/asm/pgalloc.h | 16 +++--- arch/x86/include/asm/tlb.h | 33 ------------ arch/x86/kernel/paravirt.c | 1 + arch/x86/mm/pgtable.c | 13 ++--- include/asm-generic/pgalloc.h | 61 ++++++++++++++++++++-- include/asm-generic/tlb.h | 15 +++++- include/linux/mm.h | 44 +++++----------- include/linux/mm_types.h | 9 +--- mm/memory.c | 23 +++----- mm/mmu_gather.c | 20 ++++++- 39 files changed, 233 insertions(+), 259 deletions(-) -- 2.20.1
