Bug 2535195 (CVE-2026-89971)

In the Linux kernel, the following vulnerability has been resolved:

nvme: skip the zoned limits update if the zone info query failed

nvme_query_zone_info() returns either a negative errno or a positive
NVMe status code, but nvme_update_ns_info_block() only tests for the
negative case:

	ret = nvme_query_zone_info(ns, lbaf, &zi);
	if (ret < 0)
		goto out;

If the device fails the Identify Namespace (I/O Command Set specific)
command, or the Identify Controller command issued by
nvme_set_max_append(), the positive status falls through and setup
continues with the zero-initialized zone info.  nvme_update_zone_info()
then marks the queue zoned with chunk_sectors and ns->head->zsze set to
zero.

blk_validate_zoned_limits() does not check chunk_sectors, so the limits
commit succeeds.  blk_revalidate_disk_zones() does reject the zero zone
size, but by then the limits are live and nothing rolls them back, so
I/O keeps being submitted to a zoned queue with a zero zone size and
disk_zone_no() shifts by ilog2(0):

  nvme0n1: Invalid non power of two zone size (0)
  UBSAN: shift-out-of-bounds in include/linux/blkdev.h:747:16
  shift exponent -1 is negative
   disk_zone_no include/linux/blkdev.h:747 [inline]
   bio_straddles_zones include/linux/blkdev.h:1058 [inline]
   blk_zone_wplug_handle_write block/blk-zoned.c:1423 [inline]
   blk_zone_plug_bio.cold+0x25/0x1c8 block/blk-zoned.c:1605
   blk_mq_submit_bio+0x18fb/0x2870 block/blk-mq.c:3196
   submit_bh_wbc+0x575/0x740 fs/buffer.c:2824
   __block_write_full_folio+0x728/0xdd0 fs/buffer.c:1933

Any device, firmware or NVMe-oF target that fails this one command
reaches this.

Skip the zoned limits update in that case, and log which of the two
things happened: during a revalidation the queue keeps the zone
geometry it was last validated with, and on a first scan the namespace
is registered without zoned limits, so that it is still available as a
handle for admin commands.  Neither of the paths in
nvme_query_zone_info() that return a positive status logs anything, so
the failure would otherwise be silent.

zi.zone_size is an exact indicator: every path that returns a positive
status returns before it is assigned, and after that the only failure
left is -ENODEV, which the caller already handles.

Found by FuzzNvme.