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Biederman" , Andy Lutomirski , Sebastian Andrzej Siewior , "Liam R. Howlett" , Fenghua Yu , Andrei Vagin , Barret Rhoden , Michal Hocko , "Jason A. Donenfeld" , Alexey Gladkov , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Dinglan Peng , Pedro Fonseca , Jim Huang , Huichun Feng , Chih-En Lin Subject: [PATCH v4 12/14] fs/proc: Support COW PTE with clear_refs_write Date: Tue, 7 Feb 2023 11:51:37 +0800 Message-Id: <20230207035139.272707-13-shiyn.lin@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230207035139.272707-1-shiyn.lin@gmail.com> References: <20230207035139.272707-1-shiyn.lin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org Before clearing the entry in COW-ed PTE, break COW PTE first. Signed-off-by: Chih-En Lin --- fs/proc/task_mmu.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index af1c49ae11b1..94958422aede 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1196,6 +1196,11 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr, if (pmd_trans_unstable(pmd)) return 0; + /* Only break COW when we modify the soft-dirty bit. */ + if (cp->type == CLEAR_REFS_SOFT_DIRTY && + break_cow_pte(vma, pmd, addr)) + return 0; + pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); for (; addr != end; pte++, addr += PAGE_SIZE) { ptent = *pte;