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Fri, 14 Feb 2020 17:06:33 +0000 (UTC) Received: by mail-pl1-f194.google.com with SMTP id c23so3951590plz.4 for ; Fri, 14 Feb 2020 09:06:33 -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=V7GUkh8wE1dRQiutiAZwQygV0oqWtMLGFWC+ZDS/JnU=; b=RQvOq32m45tdZVuQ4eP1UET1YZUzdiMgqS7sSPeokFVt7jEldPUoBqPTKGstnRngbF 75+1ncGimpxQlYmLre/iK7NDvLq5nH9Hi2GOxUwGhbRCZJZt2puGtJKk1yDtaNxdvTOa H/HYX/Zmw9vTr3fPSoY7uBY66RtNlMV/AMAWXeRe+em474RVFHaMWlLU35ynOr5o0Aln 3w27QgjvOu2G2AsRfDdNSepSUB0fIO/aFIzpGmYcuoM5LFW+01oXGF0iKP2e7kzay49e Mv30kROuXKTJkKiBAtSpcvfYw77pEgG193ErM30jobYpwJHikPO41vYt6EZFzgMttboN PzsA== 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=V7GUkh8wE1dRQiutiAZwQygV0oqWtMLGFWC+ZDS/JnU=; 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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 bbbfea93396a..762a68205e65 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1117,6 +1117,8 @@ int do_madvise(struct task_struct *task, struct mm_= struct *mm, 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); } @@ -1167,6 +1169,7 @@ int do_madvise(struct task_struct *task, struct mm_= struct *mm, } out: blk_finish_plug(&plug); +skip_mm: if (write) up_write(&mm->mmap_sem); else --=20 2.25.0.265.gbab2e86ba0-goog