mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-09-22 09:34:56 +02:00
Jakub Kicinski
21742be898
Breno Leitao says:
====================
netpoll: Use RCU primitives for npinfo pointer access
The net_device->npinfo pointer is marked with __rcu, indicating it requires
proper RCU access primitives:
struct net_device {
...
struct netpoll_info __rcu *npinfo;
...
};
Direct access to this pointer can lead to issues such as:
- Compiler incorrectly caching/reusing stale pointer values
- Missing memory ordering guarantees
- Non-atomic pointer loads
Replace direct NULL checks of npinfo with rcu_access_pointer(),
which provides the necessary memory ordering guarantees without the
overhead of a full RCU dereference, since we only need to verify
if the pointer is NULL.
In both cases, the RCU read lock is not held when the function is being
called. I checked that by using lockdep_assert_in_rcu_read_lock(), and
seeing the warning on both cases.
====================
Link: https://patch.msgid.link/20241118-netpoll_rcu-v1-0-a1888dcb4a02@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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 reStructuredText 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.