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authorMatthew Wilcox (Oracle) <willy@infradead.org>2022-06-07 21:45:53 +0200
committerMatthew Wilcox (Oracle) <willy@infradead.org>2022-06-09 22:24:25 +0200
commit6bf74cddcffac0bc5ee0fad724aac778d2e53f75 (patch)
treeed0e4594baaf65b943a2a522ebcba63bcc4e69f4
parentMerge tag 'fs_for_v5.19-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git... (diff)
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filemap: Don't release a locked folio
We must hold a reference over the call to filemap_release_folio(), otherwise the page cache will put the last reference to the folio before we unlock it, leading to splats like this: BUG: Bad page state in process u8:5 pfn:1ab1f4 page:ffffea0006ac7d00 refcount:0 mapcount:0 mapping:0000000000000000 index:0x28b1de pfn:0x1ab1f4 flags: 0x17ff80000040001(locked|reclaim|node=0|zone=2|lastcpupid=0xfff) raw: 017ff80000040001 dead000000000100 dead000000000122 0000000000000000 raw: 000000000028b1de 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set It's an error path, so it doesn't see much testing. Reported-by: Darrick J. Wong <djwong@kernel.org> Fixes: a42634a6c07d ("readahead: Use a folio in read_pages()") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
-rw-r--r--mm/readahead.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/readahead.c b/mm/readahead.c
index 415c39d764ea..57a015108254 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -164,12 +164,14 @@ static void read_pages(struct readahead_control *rac)
while ((folio = readahead_folio(rac)) != NULL) {
unsigned long nr = folio_nr_pages(folio);
+ folio_get(folio);
rac->ra->size -= nr;
if (rac->ra->async_size >= nr) {
rac->ra->async_size -= nr;
filemap_remove_folio(folio);
}
folio_unlock(folio);
+ folio_put(folio);
}
} else {
while ((folio = readahead_folio(rac)) != NULL)