From: Minchan Kim <minchan@xxxxxxxxxx> Subject: mm: validate inode in mapping_set_error() The swap address_space doesn't have host. Thus, it makes kernel crash once swap write meets error. Fix it. Link: https://lkml.kernel.org/r/20201010000650.750063-1-minchan@xxxxxxxxxx Fixes: 735e4ae5ba28 ("vfs: track per-sb writeback errors and report them to syncfs") Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> Acked-by: Jeff Layton <jlayton@xxxxxxxxxx> Cc: Jan Kara <jack@xxxxxxx> Cc: Andres Freund <andres@xxxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/pagemap.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/include/linux/pagemap.h~mm-validate-inode-in-mapping_set_error +++ a/include/linux/pagemap.h @@ -54,7 +54,8 @@ static inline void mapping_set_error(str __filemap_set_wb_err(mapping, error); /* Record it in superblock */ - errseq_set(&mapping->host->i_sb->s_wb_err, error); + if (mapping->host) + errseq_set(&mapping->host->i_sb->s_wb_err, error); /* Record it in flags for now, for legacy callers */ if (error == -ENOSPC) _
