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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2022-06-07 15:45:53 -0400 |
|---|---|---|
| committer | Matthew Wilcox (Oracle) <willy@infradead.org> | 2022-06-09 16:24:25 -0400 |
| commit | 6bf74cddcffac0bc5ee0fad724aac778d2e53f75 (patch) | |
| tree | ed0e4594baaf65b943a2a522ebcba63bcc4e69f4 /mm | |
| parent | 3d9f55c57bc3659f986acc421eac431ff6edcc83 (diff) | |
| download | lwn-6bf74cddcffac0bc5ee0fad724aac778d2e53f75.tar.gz lwn-6bf74cddcffac0bc5ee0fad724aac778d2e53f75.zip | |
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>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/readahead.c | 2 |
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) |