linux.git/drivers/net/netdevsim/psp.c, branch v7.1-rc4 Linux kernel source tree netdevsim: psp: rcu protect psp_dev reference 2026-05-07T00:39:20+00:00 Daniel Zahka daniel.zahka@gmail.com 2026-05-05T10:42:25+00:00 07bdec3fc737aac7f4c273aafa803d353174c43e There are two issues with the way psp_dev is used in nsim_do_psp(): 1. There is no check for IS_ERR() on the peers psp_dev, before dereferencing. 2. The refcount on this psp_dev can be dropped by nsim_psp_rereg_write() To fix this, we can make netdevsim's reference to its psp_dev an rcu reference, and then nsim_do_psp() can read the fields it needs from an rcu critical section. Fixes: f857478d6206 ("netdevsim: a basic test PSP implementation") Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20260505-psd-rcu-v1-3-a8f69ec1ab96@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
There are two issues with the way psp_dev is used in nsim_do_psp():

1. There is no check for IS_ERR() on the peers psp_dev, before
   dereferencing.
2. The refcount on this psp_dev can be dropped by
   nsim_psp_rereg_write()

To fix this, we can make netdevsim's reference to its psp_dev an rcu
reference, and then nsim_do_psp() can read the fields it needs from an
rcu critical section.

Fixes: f857478d6206 ("netdevsim: a basic test PSP implementation")
Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260505-psd-rcu-v1-3-a8f69ec1ab96@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
netdevsim: psp: serialize calls to nsim_psp_uninit() 2026-05-07T00:39:20+00:00 Daniel Zahka daniel.zahka@gmail.com 2026-05-05T10:42:24+00:00 24c96a42006ee27a078ec8c631c906dea8a3ca6d The debugfs write handler, nsim_psp_rereg_write(), can race against nsim_destroy() and against itself, causing nsim_psp_uninit() to run more than once concurrently. Two complementary changes serialize all callers: 1. Delete the psp_rereg debugfs file from nsim_psp_uninit() before doing the actual teardown. debugfs_remove() drains any in-flight writers and prevents new ones from starting. 2. Add a mutex around the body of nsim_psp_rereg_write() so that two concurrent userspace writers cannot both enter the teardown path at once. The teardown work itself is moved into a new __nsim_psp_uninit() that the rereg handler calls under the mutex, while the public nsim_psp_uninit() wraps it with the debugfs_remove()/mutex_destroy() pair so nsim_destroy() doesn't have to know about the psp internals. Fixes: f857478d6206 ("netdevsim: a basic test PSP implementation") Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20260505-psd-rcu-v1-2-a8f69ec1ab96@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
The debugfs write handler, nsim_psp_rereg_write(), can race against
nsim_destroy() and against itself, causing nsim_psp_uninit() to run
more than once concurrently. Two complementary changes serialize all
callers:

1. Delete the psp_rereg debugfs file from nsim_psp_uninit() before
   doing the actual teardown. debugfs_remove() drains any in-flight
   writers and prevents new ones from starting.

2. Add a mutex around the body of nsim_psp_rereg_write() so that two
   concurrent userspace writers cannot both enter the teardown path
   at once.

The teardown work itself is moved into a new __nsim_psp_uninit() that
the rereg handler calls under the mutex, while the public
nsim_psp_uninit() wraps it with the debugfs_remove()/mutex_destroy()
pair so nsim_destroy() doesn't have to know about the psp internals.

Fixes: f857478d6206 ("netdevsim: a basic test PSP implementation")
Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260505-psd-rcu-v1-2-a8f69ec1ab96@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
netdevsim: use u64_stats_t with u64_stats_sync properly 2026-01-27T03:53:36+00:00 David Yang mmyangfl@gmail.com 2026-01-23T21:10:55+00:00 5c05b3dbccb17ddd6515a6c749feee9b657a5640 On 64bit arches, struct u64_stats_sync is empty and provides no help against load/store tearing. Convert to u64_stats_t to ensure atomic operations. Signed-off-by: David Yang <mmyangfl@gmail.com> Link: https://patch.msgid.link/20260123211101.2929547-1-mmyangfl@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
On 64bit arches, struct u64_stats_sync is empty and provides no help
against load/store tearing. Convert to u64_stats_t to ensure atomic
operations.

Signed-off-by: David Yang <mmyangfl@gmail.com>
Link: https://patch.msgid.link/20260123211101.2929547-1-mmyangfl@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
netdevsim: implement psp device stats 2025-11-08T02:53:57+00:00 Daniel Zahka daniel.zahka@gmail.com 2025-11-06T00:26:06+00:00 178f0763c5f3cf710062ddf2e4d659127fee66b2 For now only tx/rx packets/bytes are reported. This is not compliant with the PSP Architecture Specification. Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Link: https://patch.msgid.link/20251106002608.1578518-6-daniel.zahka@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
For now only tx/rx packets/bytes are reported. This is not compliant
with the PSP Architecture Specification.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20251106002608.1578518-6-daniel.zahka@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
netdevsim: a basic test PSP implementation 2025-09-30T13:17:21+00:00 Jakub Kicinski kuba@kernel.org 2025-09-27T22:54:13+00:00 f857478d62066ee94831a5e0679fc18c246cd534 Provide a PSP implementation for netdevsim. Use psp_dev_encapsulate() and psp_dev_rcv() to do actual encapsulation and decapsulation on skbs, but perform no encryption or decryption. In order to make encryption with a bad key result in a drop on the peer's rx side, we stash our psd's generation number in the first byte of each key before handing to the peer. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Co-developed-by: Daniel Zahka <daniel.zahka@gmail.com> Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Link: https://patch.msgid.link/20250927225420.1443468-2-kuba@kernel.org Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
Provide a PSP implementation for netdevsim.

Use psp_dev_encapsulate() and psp_dev_rcv() to do actual encapsulation
and decapsulation on skbs, but perform no encryption or decryption. In
order to make encryption with a bad key result in a drop on the peer's
rx side, we stash our psd's generation number in the first byte of each
key before handing to the peer.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Co-developed-by: Daniel Zahka <daniel.zahka@gmail.com>
Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20250927225420.1443468-2-kuba@kernel.org
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>