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From: Andrew Morton <akpm@linux-foundation.org>
To: adrien+dev@schischi.me, akpm@linux-foundation.org,
	drosen@google.com, groeck@chromium.org, hch@lst.de,
	linux-mm@kvack.org, mm-commits@vger.kernel.org,
	nicolas.prochazka@gmail.com, phillip@squashfs.org.uk,
	pliard@google.com, shimada@walbrix.com, stable@vger.kernel.org,
	torvalds@linux-foundation.org
Subject: [patch 09/11] squashfs: avoid bio_alloc() failure with 1Mbyte blocks
Date: Thu, 20 Aug 2020 17:42:21 -0700	[thread overview]
Message-ID: <20200821004221.zUskNqmfM%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200820174132.67fd4a7a9359048f807a533b@linux-foundation.org>

From: Phillip Lougher <phillip@squashfs.org.uk>
Subject: squashfs: avoid bio_alloc() failure with 1Mbyte blocks

This is a regression introduced by the patch "migrate from ll_rw_block
usage to BIO".

Bio_alloc() is limited to 256 pages (1 Mbyte).  This can cause a failure
when reading 1 Mbyte block filesystems.  The problem is a datablock can be
fully (or almost uncompressed), requiring 256 pages, but, because blocks
are not aligned to page boundaries, it may require 257 pages to read.

Bio_kmalloc() can handle 1024 pages, and so use this for the edge
condition.

Link: http://lkml.kernel.org/r/20200815035637.15319-1-phillip@squashfs.org.uk
Fixes: 93e72b3c612a ("squashfs: migrate from ll_rw_block usage to BIO")
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Reported-by: Nicolas Prochazka <nicolas.prochazka@gmail.com>
Reported-by: Tomoatsu Shimada <shimada@walbrix.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Cc: Philippe Liard <pliard@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Adrien Schildknecht <adrien+dev@schischi.me>
Cc: Daniel Rosenberg <drosen@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/squashfs/block.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/fs/squashfs/block.c~squashfs-avoid-bio_alloc-failure-with-1mbyte-blocks
+++ a/fs/squashfs/block.c
@@ -87,7 +87,11 @@ static int squashfs_bio_read(struct supe
 	int error, i;
 	struct bio *bio;
 
-	bio = bio_alloc(GFP_NOIO, page_count);
+	if (page_count <= BIO_MAX_PAGES)
+		bio = bio_alloc(GFP_NOIO, page_count);
+	else
+		bio = bio_kmalloc(GFP_NOIO, page_count);
+
 	if (!bio)
 		return -ENOMEM;
 
_


  parent reply	other threads:[~2020-08-21  0:42 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-21  0:41 incoming Andrew Morton
2020-08-21  0:41 ` [patch 01/11] mailmap: add Andi Kleen Andrew Morton
2020-08-21  0:41 ` [patch 02/11] hugetlb_cgroup: convert comma to semicolon Andrew Morton
2020-08-21  0:42 ` [patch 03/11] khugepaged: adjust VM_BUG_ON_MM() in __khugepaged_enter() Andrew Morton
2020-08-21  0:42 ` [patch 04/11] mm/vunmap: add cond_resched() in vunmap_pmd_range Andrew Morton
2020-08-21  0:42 ` [patch 05/11] mm/rodata_test.c: fix missing function declaration Andrew Morton
2020-08-21  0:42 ` [patch 06/11] romfs: fix uninitialized memory leak in romfs_dev_read() Andrew Morton
2020-08-21  0:42 ` [patch 07/11] kernel/relay.c: fix memleak on destroy relay channel Andrew Morton
2020-08-21  0:42 ` [patch 08/11] uprobes: __replace_page() avoid BUG in munlock_vma_page() Andrew Morton
2020-08-21  0:42 ` Andrew Morton [this message]
2020-08-21  0:42 ` [patch 10/11] mm: include CMA pages in lowmem_reserve at boot Andrew Morton
2020-08-21  0:42 ` [patch 11/11] mm, page_alloc: fix core hung in free_pcppages_bulk() Andrew Morton

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