From: Gao Xiang gaoxiang25@huawei.com
Richard observed a forever loop of erofs_read_raw_page() [1] which can be generated by forcely setting ->u.i_blkaddr to 0xdeadbeef (as my understanding block layer can handle access beyond end of device correctly).
After digging into that, it seems the problem is highly related with directories and then I found the root cause is an improper error handling in erofs_readdir().
Let's fix it now.
[1] https://lore.kernel.org/r/1746679415.68815.1566076790942.JavaMail.zimbra@nod...
Reported-by: Richard Weinberger richard@nod.at Fixes: 3aa8ec716e52 ("staging: erofs: add directory operations") Cc: stable@vger.kernel.org # 4.19+ Signed-off-by: Gao Xiang gaoxiang25@huawei.com ---
Which is based on the following patch as well https://lore.kernel.org/r/20190816071142.8633-1-gaoxiang25@huawei.com/
and https://lore.kernel.org/r/20190817082313.21040-1-hsiangkao@aol.com/ can still be properly applied after this patch.
drivers/staging/erofs/dir.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/erofs/dir.c b/drivers/staging/erofs/dir.c index 5f38382637e6..f2d7539589e4 100644 --- a/drivers/staging/erofs/dir.c +++ b/drivers/staging/erofs/dir.c @@ -82,8 +82,12 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx) unsigned int nameoff, maxsize;
dentry_page = read_mapping_page(mapping, i, NULL); - if (IS_ERR(dentry_page)) - continue; + if (IS_ERR(dentry_page)) { + errln("fail to readdir of logical block %u of nid %llu", + i, EROFS_V(dir)->nid); + err = PTR_ERR(dentry_page); + break; + }
de = (struct erofs_dirent *)kmap(dentry_page);