From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from madrid.collaboradmins.com (madrid.collaboradmins.com [46.235.227.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FA55F9DF for ; Thu, 11 Jan 2024 08:48:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="MyiOfUru" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1704962916; bh=gflHEkCtZCmwgfIS8rr2o7AExOCHAZTyAKAlUQhbSiA=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=MyiOfUrumz7b5nTsabxHteMpzN7xlDrp6SKJZfTgbB1diocrBU8bbPm/U0n9X/BMs iBFEJairFm1vyV/EJ2ZvCqkZPquIhRtiSehYH3WPA9B90oKLBtio/woDetCIBwptoY hOkMwg1BpfMj8g4zLn1rS7sV/6Xzjr75TSqh8QG1WjRQnOZSshtDccDFSDTEXCcoP7 OCWc9fagZho7Kyz0OMHztf0mOCe4jUgER82vo8cCbErepO+UC2ErYZ5VBD+FN8n+FR k0vlz19II9y6LpO+bL9YBt1lWrsZvJy3t5Rf74LWuApG+gDUBAJJV1b9PSaFxb2wcv fCy1KPRXZo2DQ== Received: from [100.96.234.34] (cola.collaboradmins.com [195.201.22.229]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: usama.anjum) by madrid.collaboradmins.com (Postfix) with ESMTPSA id 1B534378140A; Thu, 11 Jan 2024 08:48:31 +0000 (UTC) Message-ID: Date: Thu, 11 Jan 2024 13:48:38 +0500 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: Muhammad Usama Anjum , linmiaohe@huawei.com, mike.kravetz@oracle.com, naoya.horiguchi@nec.com, akpm@linux-foundation.org, songmuchun@bytedance.com, shy828301@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, jthoughton@google.com, "kernel@collabora.com" , "Matthew Wilcox (Oracle)" Subject: Re: [PATCH v4 4/4] selftests/mm: add tests for HWPOISON hugetlbfs read Content-Language: en-US To: Sidhartha Kumar , Jiaqi Yan References: <20230713001833.3778937-1-jiaqiyan@google.com> <20230713001833.3778937-5-jiaqiyan@google.com> <079335ab-190f-41f7-b832-6ffe7528fd8b@collabora.com> From: Muhammad Usama Anjum In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 1/11/24 7:32 AM, Sidhartha Kumar wrote: > On 1/10/24 2:15 AM, Muhammad Usama Anjum wrote: >> On 1/10/24 11:49 AM, Muhammad Usama Anjum wrote: >>> On 1/6/24 2:13 AM, Jiaqi Yan wrote: >>>> On Thu, Jan 4, 2024 at 10:27 PM Muhammad Usama Anjum >>>> wrote: >>>>> >>>>> Hi, >>>>> >>>>> I'm trying to convert this test to TAP as I think the failures >>>>> sometimes go >>>>> unnoticed on CI systems if we only depend on the return value of the >>>>> application. I've enabled the following configurations which aren't >>>>> already >>>>> present in tools/testing/selftests/mm/config: >>>>> CONFIG_MEMORY_FAILURE=y >>>>> CONFIG_HWPOISON_INJECT=m >>>>> >>>>> I'll send a patch to add these configs later. Right now I'm trying to >>>>> investigate the failure when we are trying to inject the poison page by >>>>> madvise(MADV_HWPOISON). I'm getting device busy every single time. The >>>>> test >>>>> fails as it doesn't expect any business for the hugetlb memory. I'm not >>>>> sure if the poison handling code has issues or test isn't robust enough. >>>>> >>>>> ./hugetlb-read-hwpoison >>>>> Write/read chunk size=0x800 >>>>>   ... HugeTLB read regression test... >>>>>   ...  ... expect to read 0x200000 bytes of data in total >>>>>   ...  ... actually read 0x200000 bytes of data in total >>>>>   ... HugeTLB read regression test...TEST_PASSED >>>>>   ... HugeTLB read HWPOISON test... >>>>> [    9.280854] Injecting memory failure for pfn 0x102f01 at process >>>>> virtual >>>>> address 0x7f28ec101000 >>>>> [    9.282029] Memory failure: 0x102f01: huge page still referenced by >>>>> 511 >>>>> users >>>>> [    9.282987] Memory failure: 0x102f01: recovery action for huge >>>>> page: Failed >>>>>   ...  !!! MADV_HWPOISON failed: Device or resource busy >>>>>   ... HugeTLB read HWPOISON test...TEST_FAILED >>>>> >>>>> I'm testing on v6.7-rc8. Not sure if this was working previously or not. >>>> >>>> Thanks for reporting this, Usama! >>>> >>>> I am also able to repro MADV_HWPOISON failure at "501a06fe8e4c >>>> (akpm/mm-stable, mm-stable) zswap: memcontrol: implement zswap >>>> writeback disabling." >>>> >>>> Then I checked out the earliest commit "ba91e7e5d15a (HEAD -> Base) >>>> selftests/mm: add tests for HWPOISON hugetlbfs read". The >>>> MADV_HWPOISON injection works and and the test passes: >>>> >>>>   ... HugeTLB read HWPOISON test... >>>>   ...  ... expect to read 0x101000 bytes of data in total >>>>   ...  !!! read failed: Input/output error >>>>   ...  ... actually read 0x101000 bytes of data in total >>>>   ... HugeTLB read HWPOISON test...TEST_PASSED >>>>   ... HugeTLB seek then read HWPOISON test... >>>>   ...  ... init val=4 with offset=0x102000 >>>>   ...  ... expect to read 0xfe000 bytes of data in total >>>>   ...  ... actually read 0xfe000 bytes of data in total >>>>   ... HugeTLB seek then read HWPOISON test...TEST_PASSED >>>>   ... >>>> >>>> [ 2109.209225] Injecting memory failure for pfn 0x3190d01 at process >>>> virtual address 0x7f75e3101000 >>>> [ 2109.209438] Memory failure: 0x3190d01: recovery action for huge >>>> page: Recovered >>>> ... >>>> >>>> I think something in between broken MADV_HWPOISON on hugetlbfs, and we >>>> should be able to figure it out via bisection (and of course by >>>> reading delta commits between them, probably related to page >>>> refcount). >>> Thank you for this information. >>> >>>> >>>> That being said, I will be on vacation from tomorrow until the end of >>>> next week. So I will get back to this after next weekend. Meanwhile if >>>> you want to go ahead and bisect the problematic commit, that will be >>>> very much appreciated. >>> I'll try to bisect and post here if I find something. >> Found the culprit commit by bisection: >> >> a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 >> mm/filemap: remove hugetlb special casing in filemap.c >> >> hugetlb-read-hwpoison started failing from this patch. I've added the >> author of this patch to this bug report. >> > Hi Usama, > > Thanks for pointing this out. After debugging, the below diff seems to fix > the issue and allows the tests to pass again. Could you test it on your > configuration as well just to confirm. > > Thanks, > Sidhartha > > diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c > index 36132c9125f9..3a248e4f7e93 100644 > --- a/fs/hugetlbfs/inode.c > +++ b/fs/hugetlbfs/inode.c > @@ -340,7 +340,7 @@ static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, > struct iov_iter *to) >                 } else { >                         folio_unlock(folio); > > -                       if (!folio_test_has_hwpoisoned(folio)) > +                       if (!folio_test_hwpoison(folio)) >                                 want = nr; >                         else { >                                 /* > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index d8c853b35dbb..87f6bf7d8bc1 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -973,7 +973,7 @@ struct page_state { >  static bool has_extra_refcount(struct page_state *ps, struct page *p, >                                bool extra_pins) >  { > -       int count = page_count(p) - 1; > +       int count = page_count(p) - folio_nr_pages(page_folio(p)); > >         if (extra_pins) >                 count -= 1; > Tested the patch, it fixes the test. Please send this patch. Tested-by: Muhammad Usama Anjum -- BR, Muhammad Usama Anjum