Michal Kazior 7e71fbc68d wifi: cfg80211: fix missing interfaces when dumping
[ Upstream commit a6e4f85d3820d00694ed10f581f4c650445dbcda ]

The nl80211_dump_interface() supports resumption
in case nl80211_send_iface() doesn't have the
resources to complete its work.

The logic would store the progress as iteration
offsets for rdev and wdev loops.

However the logic did not properly handle
resumption for non-last rdev. Assuming a system
with 2 rdevs, with 2 wdevs each, this could
happen:

 dump(cb=[0, 0]):
  if_start=cb[1] (=0)
  send rdev0.wdev0 -> ok
  send rdev0.wdev1 -> yield
  cb[1] = 1

 dump(cb=[0, 1]):
  if_start=cb[1] (=1)
  send rdev0.wdev1 -> ok
  // since if_start=1 the rdev0.wdev0 got skipped
  // through if_idx < if_start
  send rdev1.wdev1 -> ok

The if_start needs to be reset back to 0 upon wdev
loop end.

The problem is actually hard to hit on a desktop,
and even on most routers. The prerequisites for
this manifesting was:
 - more than 1 wiphy
 - a few handful of interfaces
 - dump without rdev or wdev filter

I was seeing this with 4 wiphys 9 interfaces each.
It'd miss 6 interfaces from the last wiphy
reported to userspace.

Signed-off-by: Michal Kazior <michal@plume.com>
Link: https://msgid.link/20240116142340.89678-1-kazikcz@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-01 13:16:43 +01:00
2024-03-01 13:16:43 +01:00
2020-10-17 11:18:18 -07:00
2023-06-21 15:45:38 +02:00
2024-02-23 08:42:33 +01:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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