Linux kernel source tree
Go to file
Chuck Lever bf94dea7fd svcrdma: Release transport resources synchronously
NFSD has always supported added network listeners. The new netlink
protocol now enables the removal of listeners.

Olga noticed that if an RDMA listener is removed and immediately
re-added, the deferred __svc_rdma_free() function might not have
run yet, so some or all of the old listener's RDMA resources
linger, which prevents a new listener on the same address from
being created.

Also, svc_xprt_free() does a module_put() just after calling
->xpo_free(). That means if there is deferred work going on, the
module could be unloaded before that work is even started,
resulting in a UAF.

Neil asks:
> What particular part of __svc_rdma_free() needs to run in order for a
> subsequent registration to succeed?
> Can that bit be run directory from svc_rdma_free() rather than be
> delayed?
> (I know almost nothing about rdma so forgive me if the answers to these
> questions seems obvious)

The reasons I can recall are:

 - Some of the transport tear-down work can sleep
 - Releasing a cm_id is tricky and can deadlock

We might be able to mitigate the second issue with judicious
application of transport reference counting.

Reported-by: Olga Kornievskaia <okorniev@redhat.com>
Closes: https://lore.kernel.org/linux-nfs/20250821204328.89218-1-okorniev@redhat.com/
Suggested-by: NeilBrown <neil@brown.name>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-11-16 18:20:11 -05:00
arch 7 hotfixes. 5 are cc:stable, 4 are against mm/. 2025-11-16 13:31:14 -08:00
block block-6.18-20251031 2025-10-31 12:57:19 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push contains the following changes: 2025-10-10 08:56:16 -07:00
Documentation sound fixes for 6.18-rc6 2025-11-14 12:50:08 -08:00
drivers firewire fixes for 6.18-rc6 2025-11-16 07:08:28 -08:00
fs More NFS Client Bugfixes for Linux 6.18-rc 2025-11-14 13:44:23 -08:00
include 7 hotfixes. 5 are cc:stable, 4 are against mm/. 2025-11-16 13:31:14 -08:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/rsrc: don't use blk_rq_nr_phys_segments() as number of bvecs 2025-11-12 08:25:33 -07:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel 7 hotfixes. 5 are cc:stable, 4 are against mm/. 2025-11-16 13:31:14 -08:00
lib lib/test_kho: check if KHO is enabled 2025-11-15 10:52:01 -08:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm 7 hotfixes. 5 are cc:stable, 4 are against mm/. 2025-11-16 13:31:14 -08:00
net svcrdma: Release transport resources synchronously 2025-11-16 18:20:11 -05:00
rust rust: Add -fno-isolate-erroneous-paths-dereference to bindgen_skip_c_flags 2025-11-10 08:37:06 +08:00
samples Char/Misc/IIO/Binder changes for 6.18-rc1 2025-10-04 16:26:32 -07:00
scripts Rust fixes for v6.18 (2nd) 2025-11-14 15:36:15 -08:00
security integrity-v6.18 2025-10-05 10:48:33 -07:00
sound ALSA: usb-audio: Add native DSD quirks for PureAudio DAC series 2025-11-14 14:19:47 +01:00
tools perf tools fixes for v6.18: 2nd batch 2025-11-16 13:45:03 -08:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: guest_memfd: Remove bindings on memslot deletion when gmem is dying 2025-11-04 09:16:53 -08:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap 7 hotfixes. 5 are cc:stable, 4 are against mm/. 2025-11-16 13:31:14 -08:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.rustfmt.toml
COPYING
CREDITS MAINTAINERS: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS 7 hotfixes. 5 are cc:stable, 4 are against mm/. 2025-11-16 13:31:14 -08:00
Makefile Linux 6.18-rc6 2025-11-16 14:25:38 -08:00
README

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.