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From: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
To: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	akpm@linux-foundation.org, songmuchun@bytedance.com,
	mike.kravetz@oracle.com, willy@infradead.org,
	jhubbard@nvidia.com, linux-s390@vger.kernel.org
Subject: Re: [PATCH 8/9] mm/hugetlb: convert hugetlb_wp() to take in a folio
Date: Tue, 24 Jan 2023 16:23:46 +0100	[thread overview]
Message-ID: <20230124162346.404985e8@thinkpad> (raw)
In-Reply-To: <20230119211446.54165-9-sidhartha.kumar@oracle.com>

On Thu, 19 Jan 2023 13:14:45 -0800
Sidhartha Kumar <sidhartha.kumar@oracle.com> wrote:

[...]
>  	page = pte_page(entry);
> -	if (page != pagecache_page)
> +	if (page_folio(page) != pagecache_folio)
>  		if (!trylock_page(page)) {
>  			need_wait_lock = 1;
>  			goto out_ptl;
>  		}
>  
> -	get_page(page);
> +	folio_get(pagecache_folio);
>  

We get a kernel crash on s390 in mprotect testcase from libhugetlbfs
testsuite, starting with next-20230120, bisected to this commit.

We get here with pagecache_folio == NULL, and crash in folio_get().
It doesn´t seem right to replace the get_page() with folio_get()
here, the matching put_page() at out_put_page: also wasn't changed
correspondingly. Also, pagecache_folio == NULL seems to be a valid
case here, on all architectures.

Reverting this folio_get() to get_page() fixes the crash. Not sure
though if I missed something. I think you only want to replace
pagecache_page with pagecache_folio, like in the rest of the commit,
and not page -> pagecache_folio for this get_page().

  reply	other threads:[~2023-01-24 15:24 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-19 21:14 [PATCH 0/9] convert hugetlb fault functions to folios Sidhartha Kumar
2023-01-19 21:14 ` [PATCH 1/9] mm/hugetlb: convert hugetlb_install_page " Sidhartha Kumar
2023-01-20 23:21   ` Mike Kravetz
2023-01-19 21:14 ` [PATCH 2/9] mm/hugetlb: convert hugetlbfs_pagecache_present() " Sidhartha Kumar
2023-01-20  5:43   ` Matthew Wilcox
2023-01-20 23:40     ` Mike Kravetz
2023-01-19 21:14 ` [PATCH 3/9] mm/hugetlb: convert putback_active_hugepage to take in a folio Sidhartha Kumar
2023-01-20  5:48   ` Matthew Wilcox
2023-01-20 23:47   ` Mike Kravetz
2023-01-19 21:14 ` [PATCH 4/9] mm/rmap: change hugepage_add_new_anon_rmap " Sidhartha Kumar
2023-01-20  6:00   ` Matthew Wilcox
2023-01-20 20:45     ` Sidhartha Kumar
2023-01-20 21:17       ` Matthew Wilcox
2023-01-20 22:05         ` Sidhartha Kumar
2023-01-19 21:14 ` [PATCH 5/9] mm/hugetlb: convert alloc_huge_page to alloc_hugetlb_folio Sidhartha Kumar
2023-01-19 21:14 ` [PATCH 6/9] mm/hugetlb: convert restore_reserve_on_error to take in a folio Sidhartha Kumar
2023-01-19 21:14 ` [PATCH 7/9] mm/hugetlb: convert hugetlb_add_to_page_cache " Sidhartha Kumar
2023-01-19 21:14 ` [PATCH 8/9] mm/hugetlb: convert hugetlb_wp() " Sidhartha Kumar
2023-01-24 15:23   ` Gerald Schaefer [this message]
2023-01-24 18:38     ` Sidhartha Kumar
2023-01-19 21:14 ` [PATCH 9/9] Documentation/mm: update hugetlbfs documentation to mention alloc_hugetlb_folio Sidhartha Kumar

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