| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.7 233/244] RISC-V: Acquire mmap lock before invoking walk_page_range | Date | Mon, 20 Jul 2020 17:38:24 +0200 |
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From: Atish Patra <atish.patra@wdc.com>
commit 0e2c09011d4de4161f615ff860a605a9186cf62a upstream.
As per walk_page_range documentation, mmap lock should be acquired by the caller before invoking walk_page_range. mmap_assert_locked gets triggered without that. The details can be found here.
http://lists.infradead.org/pipermail/linux-riscv/2020-June/010335.html
Fixes: 395a21ff859c(riscv: add ARCH_HAS_SET_DIRECT_MAP support) Signed-off-by: Atish Patra <atish.patra@wdc.com> Reviewed-by: Michel Lespinasse <walken@google.com> Reviewed-by: Zong Li <zong.li@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/riscv/mm/pageattr.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
--- a/arch/riscv/mm/pageattr.c +++ b/arch/riscv/mm/pageattr.c @@ -151,6 +151,7 @@ int set_memory_nx(unsigned long addr, in int set_direct_map_invalid_noflush(struct page *page) { + int ret; unsigned long start = (unsigned long)page_address(page); unsigned long end = start + PAGE_SIZE; struct pageattr_masks masks = { @@ -158,11 +159,16 @@ int set_direct_map_invalid_noflush(struc .clear_mask = __pgprot(_PAGE_PRESENT) }; - return walk_page_range(&init_mm, start, end, &pageattr_ops, &masks); + mmap_read_lock(&init_mm); + ret = walk_page_range(&init_mm, start, end, &pageattr_ops, &masks); + mmap_read_unlock(&init_mm); + + return ret; } int set_direct_map_default_noflush(struct page *page) { + int ret; unsigned long start = (unsigned long)page_address(page); unsigned long end = start + PAGE_SIZE; struct pageattr_masks masks = { @@ -170,7 +176,11 @@ int set_direct_map_default_noflush(struc .clear_mask = __pgprot(0) }; - return walk_page_range(&init_mm, start, end, &pageattr_ops, &masks); + mmap_read_lock(&init_mm); + ret = walk_page_range(&init_mm, start, end, &pageattr_ops, &masks); + mmap_read_unlock(&init_mm); + + return ret; } void __kernel_map_pages(struct page *page, int numpages, int enable)
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