We have been calling wait_for_unix_gc() on every sendmsg() in case
there are too many inflight AF_UNIX sockets.
This is also because the old GC implementation had poor knowledge
of the inflight sockets and had to suspect every sendmsg().
This was improved by commit d9f21b3613 ("af_unix: Try to run GC
async."), but we do not even need to call wait_for_unix_gc() if the
process is not sending AF_UNIX sockets.
The wait_for_unix_gc() call only helps when a malicious process
continues to create cyclic references, and we can detect that
in a better place and slow it down.
Let's move wait_for_unix_gc() to unix_prepare_fpl() that is called
only when AF_UNIX socket fd is passed via SCM_RIGHTS.
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251115020935.2643121-5-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We have been triggering GC on every close() if there is even one
inflight AF_UNIX socket.
This is because the old GC implementation had no idea of the graph
shape formed by SCM_RIGHTS references.
The new GC knows whether there could be a cyclic reference or not,
and we can do better.
Let's not trigger GC from close() if there is no cyclic reference
or GC is already in progress.
While at it, unix_gc() is renamed to unix_schedule_gc() as it does
not actually perform GC since commit 8b90a9f819 ("af_unix: Run
GC on only one CPU.").
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251115020935.2643121-4-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
After merging the apparmor tree, today's linux-next build (x86_64
allmodconfig) failed like this:
security/apparmor/af_unix.c: In function 'unix_state_double_lock':
security/apparmor/af_unix.c:627:17: error: implicit declaration of function 'unix_state_lock'; did you mean 'unix_state_double_lock'? [-Wimplicit-function-declaration]
627 | unix_state_lock(sk1);
| ^~~~~~~~~~~~~~~
| unix_state_double_lock
security/apparmor/af_unix.c: In function 'unix_state_double_unlock':
security/apparmor/af_unix.c:642:17: error: implicit declaration of function 'unix_state_unlock'; did you mean 'unix_state_double_lock'? [-Wimplicit-function-declaration]
642 | unix_state_unlock(sk1);
| ^~~~~~~~~~~~~~~~~
| unix_state_double_lock
Caused by commit
c05e705812 ("apparmor: add fine grained af_unix mediation")
interacting with commit
84960bf240 ("af_unix: Move internal definitions to net/unix/.")
from the net-next tree.
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://patch.msgid.link/20250326150148.72d9138d@canb.auug.org.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net/af_unix.h is included by core and some LSMs, but most definitions
need not be.
Let's move struct unix_{vertex,edge} to net/unix/garbage.c and other
definitions to net/unix/af_unix.h.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Link: https://patch.msgid.link/20250318034934.86708-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Kuniyuki Iwashima
Stephen Rothwell
Kuniyuki Iwashima