From 0c10f8a1a7ae1502ea4ea7e13f222df89c28adf4 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 29 Oct 2026 16:03:35 +0100 Subject: [PATCH] zloop: check that the zone backing file support ->{read,write}_iter I/O to backing files requires support for iter based read/write, so check for that upfront instead of dereferencing a NULL pointer later. Fixes: eb0570c7df23 ("block: new zoned loop block device driver") Reported-by: Josef Bacik Signed-off-by: Christoph Hellwig Link: https://patch.msgid.link/20261029150353.2503201-5-hch@lst.de Signed-off-by: Jens Axboe --- drivers/block/zloop.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/block/zloop.c b/drivers/block/zloop.c index f0aca9d43851..65634a39b0bf 100644 --- a/drivers/block/zloop.c +++ b/drivers/block/zloop.c @@ -1132,6 +1132,11 @@ static int zloop_init_zone(struct zloop_device *zlo, struct zloop_options *opts, return PTR_ERR(zone->file); } + if (!zone->file->f_op->read_iter || !zone->file->f_op->write_iter) { + ret = -EINVAL; + goto out_fput; + } + if (zlo->block_size) { ret = zloop_get_block_size(zlo, zone); if (ret)