4.19-stable patches

added patches:
	af_unix-suppress-false-positive-lockdep-splat-for-spin_lock-in-__unix_gc.patch

diff --git a/queue-4.19/af_unix-suppress-false-positive-lockdep-splat-for-spin_lock-in-__unix_gc.patch b/queue-4.19/af_unix-suppress-false-positive-lockdep-splat-for-spin_lock-in-__unix_gc.patch
new file mode 100644 (file)
index 0000000..e181790
--- /dev/null
+++ b/queue-4.19/af_unix-suppress-false-positive-lockdep-splat-for-spin_lock-in-__unix_gc.patch
@@ -0,0 +1,163 @@
+From 1971d13ffa84a551d29a81fdf5b5ec5be166ac83 Mon Sep 17 00:00:00 2001
+From: Kuniyuki Iwashima <kuniyu@amazon.com>
+Date: Wed, 24 Apr 2024 10:04:43 -0700
+Subject: af_unix: Suppress false-positive lockdep splat for spin_lock() in __unix_gc().
+
+From: Kuniyuki Iwashima <kuniyu@amazon.com>
+
+commit 1971d13ffa84a551d29a81fdf5b5ec5be166ac83 upstream.
+
+syzbot reported a lockdep splat regarding unix_gc_lock and
+unix_state_lock().
+
+One is called from recvmsg() for a connected socket, and another
+is called from GC for TCP_LISTEN socket.
+
+So, the splat is false-positive.
+
+Let's add a dedicated lock class for the latter to suppress the splat.
+
+Note that this change is not necessary for net-next.git as the issue
+is only applied to the old GC impl.
+
+[0]:
+WARNING: possible circular locking dependency detected
+6.9.0-rc5-syzkaller-00007-g4d2008430ce8 #0 Not tainted
+ -----------------------------------------------------
+kworker/u8:1/11 is trying to acquire lock:
+ffff88807cea4e70 (&u->lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
+ffff88807cea4e70 (&u->lock){+.+.}-{2:2}, at: __unix_gc+0x40e/0xf70 net/unix/garbage.c:302
+
+but task is already holding lock:
+ffffffff8f6ab638 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
+ffffffff8f6ab638 (unix_gc_lock){+.+.}-{2:2}, at: __unix_gc+0x117/0xf70 net/unix/garbage.c:261
+
+which lock already depends on the new lock.
+
+the existing dependency chain (in reverse order) is:
+
+ -> #1 (unix_gc_lock){+.+.}-{2:2}:
+       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
+       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
+       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
+       spin_lock include/linux/spinlock.h:351 [inline]
+       unix_notinflight+0x13d/0x390 net/unix/garbage.c:140
+       unix_detach_fds net/unix/af_unix.c:1819 [inline]
+       unix_destruct_scm+0x221/0x350 net/unix/af_unix.c:1876
+       skb_release_head_state+0x100/0x250 net/core/skbuff.c:1188
+       skb_release_all net/core/skbuff.c:1200 [inline]
+       __kfree_skb net/core/skbuff.c:1216 [inline]
+       kfree_skb_reason+0x16d/0x3b0 net/core/skbuff.c:1252
+       kfree_skb include/linux/skbuff.h:1262 [inline]
+       manage_oob net/unix/af_unix.c:2672 [inline]
+       unix_stream_read_generic+0x1125/0x2700 net/unix/af_unix.c:2749
+       unix_stream_splice_read+0x239/0x320 net/unix/af_unix.c:2981
+       do_splice_read fs/splice.c:985 [inline]
+       splice_file_to_pipe+0x299/0x500 fs/splice.c:1295
+       do_splice+0xf2d/0x1880 fs/splice.c:1379
+       __do_splice fs/splice.c:1436 [inline]
+       __do_sys_splice fs/splice.c:1652 [inline]
+       __se_sys_splice+0x331/0x4a0 fs/splice.c:1634
+       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
+       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
+       entry_SYSCALL_64_after_hwframe+0x77/0x7f
+
+ -> #0 (&u->lock){+.+.}-{2:2}:
+       check_prev_add kernel/locking/lockdep.c:3134 [inline]
+       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
+       validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
+       __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
+       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
+       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
+       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
+       spin_lock include/linux/spinlock.h:351 [inline]
+       __unix_gc+0x40e/0xf70 net/unix/garbage.c:302
+       process_one_work kernel/workqueue.c:3254 [inline]
+       process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3335
+       worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
+       kthread+0x2f0/0x390 kernel/kthread.c:388
+       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
+       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
+
+other info that might help us debug this:
+
+ Possible unsafe locking scenario:
+
+       CPU0                    CPU1
+       ----                    ----
+  lock(unix_gc_lock);
+                               lock(&u->lock);
+                               lock(unix_gc_lock);
+  lock(&u->lock);
+
+ *** DEADLOCK ***
+
+3 locks held by kworker/u8:1/11:
+ #0: ffff888015089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3229 [inline]
+ #0: ffff888015089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x17c0 kernel/workqueue.c:3335
+ #1: ffffc90000107d00 (unix_gc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3230 [inline]
+ #1: ffffc90000107d00 (unix_gc_work){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x17c0 kernel/workqueue.c:3335
+ #2: ffffffff8f6ab638 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
+ #2: ffffffff8f6ab638 (unix_gc_lock){+.+.}-{2:2}, at: __unix_gc+0x117/0xf70 net/unix/garbage.c:261
+
+stack backtrace:
+CPU: 0 PID: 11 Comm: kworker/u8:1 Not tainted 6.9.0-rc5-syzkaller-00007-g4d2008430ce8 #0
+Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
+Workqueue: events_unbound __unix_gc
+Call Trace:
+ <TASK>
+ __dump_stack lib/dump_stack.c:88 [inline]
+ dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
+ check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187
+ check_prev_add kernel/locking/lockdep.c:3134 [inline]
+ check_prevs_add kernel/locking/lockdep.c:3253 [inline]
+ validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
+ __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
+ lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
+ __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
+ _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
+ spin_lock include/linux/spinlock.h:351 [inline]
+ __unix_gc+0x40e/0xf70 net/unix/garbage.c:302
+ process_one_work kernel/workqueue.c:3254 [inline]
+ process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3335
+ worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
+ kthread+0x2f0/0x390 kernel/kthread.c:388
+ ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
+ ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
+ </TASK>
+
+Fixes: 47d8ac011fe1 ("af_unix: Fix garbage collector racing against connect()")
+Reported-and-tested-by: syzbot+fa379358c28cc87cc307@syzkaller.appspotmail.com
+Closes: https://syzkaller.appspot.com/bug?extid=fa379358c28cc87cc307
+Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
+Link: https://lore.kernel.org/r/20240424170443.9832-1-kuniyu@amazon.com
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ include/net/af_unix.h |    3 +++
+ net/unix/garbage.c    |    2 +-
+ 2 files changed, 4 insertions(+), 1 deletion(-)
+
+--- a/include/net/af_unix.h
++++ b/include/net/af_unix.h
+@@ -72,6 +72,9 @@ enum unix_socket_lock_class {
+       U_LOCK_NORMAL,
+       U_LOCK_SECOND,  /* for double locking, see unix_state_double_lock(). */
+       U_LOCK_DIAG, /* used while dumping icons, see sk_diag_dump_icons(). */
++      U_LOCK_GC_LISTENER, /* used for listening socket while determining gc
++                           * candidates to close a small race window.
++                           */
+ };
+ 
+ static inline void unix_state_lock_nested(struct sock *sk,
+--- a/net/unix/garbage.c
++++ b/net/unix/garbage.c
+@@ -264,7 +264,7 @@ void unix_gc(void)
+                       __set_bit(UNIX_GC_MAYBE_CYCLE, &u->gc_flags);
+ 
+                       if (sk->sk_state == TCP_LISTEN) {
+-                              unix_state_lock(sk);
++                              unix_state_lock_nested(sk, U_LOCK_GC_LISTENER);
+                               unix_state_unlock(sk);
+                       }
+               }

diff --git a/queue-4.19/series b/queue-4.19/series
index f2a271384235b76cdceb63bbeff5932e079bb49d..60095e367216963984e83a52d7cc4b3d15974724 100644 (file)
--- a/queue-4.19/series
+++ b/queue-4.19/series
@@ -60,3 +60,4 @@ tipc-fix-uaf-in-error-path.patch
 dyndbg-fix-old-bug_on-in-control-parser.patch
 drm-vmwgfx-fix-invalid-reads-in-fence-signaled-events.patch
 net-fix-out-of-bounds-access-in-ops_init.patch
+af_unix-suppress-false-positive-lockdep-splat-for-spin_lock-in-__unix_gc.patch