commit 0bc8061ffc733a0a246b8689b2d32a3e9204f43c upstream.
syzbot reported a WARNING in iomap_iter_done:
iomap_fiemap+0x73b/0x9b0 fs/iomap/fiemap.c:80
ioctl_fiemap fs/ioctl.c:220 [inline]
Generally, NONHEAD lclusters won't have delta[1]==0, except for crafted
images and filesystems created by pre-1.0 mkfs versions.
Previously, it would immediately bail out if delta[1]==0, which led to
inadequate decompressed lengths (thus FIEMAP is impacted). Treat it as
delta[1]=1 to work around these legacy mkfs versions.
`lclusterbits > 14` is illegal for compact indexes, error out too.
Reported-by: syzbot+6c0b301317aa0156f9eb@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/67373c0c.050a0220.2a2fcc.0079.GAE@google.com
Tested-by: syzbot+6c0b301317aa0156f9eb@syzkaller.appspotmail.com
Fixes: d95ae5e253 ("erofs: add support for the full decompressed length")
Fixes: 001b8ccd0650 ("erofs: fix compact 4B support for 16k block size")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241115173651.3339514-1-hsiangkao@linux.alibaba.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
75a0a6dde8