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charset=us-ascii Content-Disposition: inline In-Reply-To: <20220616161928.3565294-1-xianting.tian@linux.alibaba.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655454057; a=rsa-sha256; cv=none; b=K6bUV66/Dvl97jptCmwz4/viHR5BBUr6Jsr0mwoIplXXx1oPYMSo7xvqJIG5ldebdZMue8 kjZD3xXbZSg4j3cLAjw6x8NIMvbPPIST/XKZsxhpz3bcpOgWyhRgZa2xPqAokuFzk6fazH fzoqte9Wb4wbSr/xjsP3fP3I+Dt2594= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=linuxfoundation.org header.s=korg header.b=MxArUWDt; spf=pass (imf05.hostedemail.com: domain of gregkh@linuxfoundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org; dmarc=pass (policy=none) header.from=linuxfoundation.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655454057; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=TS9bd1YF/RLHj6vt27ukp7unGdDhpqLEyCZ/rGb840A=; b=veva2fG5uyEw3U4VswexrLsQgh+d/pHaYOvnhFS+4Q5liYegm73tXMHEKDvktGh0i1CFi2 6Y6jOYTjM9lyxKBV6vc3BPRVurc3W8xamRD2hK/ddi/Yi++L8L0xJgoJO9CxRUh/4Jbycs 5mALz5FeWQmmOu0fO0TAD7B/hVVMrDo= X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 5279E100091 X-Stat-Signature: dstdsyc7bqqib4kjeppzzgkfcpocx5yt Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=linuxfoundation.org header.s=korg header.b=MxArUWDt; spf=pass (imf05.hostedemail.com: domain of gregkh@linuxfoundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org; dmarc=pass (policy=none) header.from=linuxfoundation.org X-Rspam-User: X-HE-Tag: 1655454057-142401 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Jun 17, 2022 at 12:19:28AM +0800, Xianting Tian wrote: > Commit 787af64d05cd ("mm: page_alloc: validate buddy before check its migratetype.") > fixes a bug in 1dd214b8f21c and there is a similar bug in d9dddbf55667 that > can be fixed in a similar way too. > > In addition, for RISC-V arch the first 2MB RAM could be reserved for opensbi, > so it would have pfn_base=512 and mem_map began with 512th PFN when > CONFIG_FLATMEM=y. > But __find_buddy_pfn algorithm thinks the start pfn 0, it could get 0 pfn or > less than the pfn_base value. We need page_is_buddy() to verify the buddy to > prevent accessing an invalid buddy. > > Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks") > Cc: stable@vger.kernel.org > Reported-by: zjb194813@alibaba-inc.com > Reported-by: tianhu.hh@alibaba-inc.com > Signed-off-by: Xianting Tian > --- > mm/page_alloc.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index a6e682569e5b..1c423faa4b62 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -864,6 +864,9 @@ static inline void __free_one_page(struct page *page, > > buddy_idx = __find_buddy_index(page_idx, order); > buddy = page + (buddy_idx - page_idx); > + > + if (!page_is_buddy(page, buddy, order)) > + goto done_merging; > buddy_mt = get_pageblock_migratetype(buddy); > > if (migratetype != buddy_mt > -- > 2.17.1 > What is the git commit id of this change in Linus's tree? thanks, greg k-h