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Wed, 12 Feb 2020 23:40:02 +0000 (UTC) Received: by mail-pg1-f195.google.com with SMTP id w21so2023587pgl.9 for ; Wed, 12 Feb 2020 15:40:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ZMr8LhEVC9oO5IOdT1EAti6B5+7g8NKkMYB8pLjiUts=; b=FZrxKnddlcDw5zyfExhzpFB7yNfAtSGotiVUgDx7kQeEtRk96KD2mjuJAwspjEWZEN 8KQGuw5rgbMTjblF/1hERi1coEcedKQRj0A3ZDpTh/rLPLJ01OSf3UbmgfW6utovZI3H qKbek4ZUVtEesWnc8Jz1oh3eReFVrokHuT8LrXYSlGbQs0tKXLnC7cKdOT9I8H90mNP/ 6LeqDCmJSqRfYdC0SBilvY0LlpVtSqLG7Oof/zDRge1nTZaZh3bSa2QLWuT7PpN2E/V8 MufG1jDdEtKBDxSNXo3mv7bob5OGe9IF3J0ofzL96vWBtLLs9Lykq6WoQHJCnrmHn7sj g+/A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=ZMr8LhEVC9oO5IOdT1EAti6B5+7g8NKkMYB8pLjiUts=; 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KSM hints will require locking mmap_sem for write since they modify vm_flags, so for remote KSM hinting this additional check is needed. Signed-off-by: Oleksandr Natalenko Signed-off-by: Minchan Kim --- mm/madvise.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/madvise.c b/mm/madvise.c index 276b9d81c1dd..71f0ba199ae8 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1120,6 +1120,8 @@ int do_madvise(struct task_struct *task, unsigned l= ong start, if (write) { if (down_write_killable(&mm->mmap_sem)) return -EINTR; + if (current->mm !=3D mm && !mmget_still_valid(mm)) + goto skip_mm; } else { down_read(&mm->mmap_sem); } @@ -1170,6 +1172,7 @@ int do_madvise(struct task_struct *task, unsigned l= ong start, } out: blk_finish_plug(&plug); +skip_mm: if (write) up_write(&mm->mmap_sem); else --=20 2.25.0.225.g125e21ebc7-goog