5.15-stable patches

added patches:
	af_unix-drop-oob_skb-ref-before-purging-queue-in-gc.patch

diff --git a/queue-5.15/af_unix-drop-oob_skb-ref-before-purging-queue-in-gc.patch b/queue-5.15/af_unix-drop-oob_skb-ref-before-purging-queue-in-gc.patch
new file mode 100644 (file)
index 0000000..210f712
--- /dev/null
+++ b/queue-5.15/af_unix-drop-oob_skb-ref-before-purging-queue-in-gc.patch
@@ -0,0 +1,106 @@
+From aa82ac51d63328714645c827775d64dbfd9941f3 Mon Sep 17 00:00:00 2001
+From: Kuniyuki Iwashima <kuniyu@amazon.com>
+Date: Mon, 19 Feb 2024 09:46:57 -0800
+Subject: af_unix: Drop oob_skb ref before purging queue in GC.
+
+From: Kuniyuki Iwashima <kuniyu@amazon.com>
+
+commit aa82ac51d63328714645c827775d64dbfd9941f3 upstream.
+
+syzbot reported another task hung in __unix_gc().  [0]
+
+The current while loop assumes that all of the left candidates
+have oob_skb and calling kfree_skb(oob_skb) releases the remaining
+candidates.
+
+However, I missed a case that oob_skb has self-referencing fd and
+another fd and the latter sk is placed before the former in the
+candidate list.  Then, the while loop never proceeds, resulting
+the task hung.
+
+__unix_gc() has the same loop just before purging the collected skb,
+so we can call kfree_skb(oob_skb) there and let __skb_queue_purge()
+release all inflight sockets.
+
+[0]:
+Sending NMI from CPU 0 to CPUs 1:
+NMI backtrace for cpu 1
+CPU: 1 PID: 2784 Comm: kworker/u4:8 Not tainted 6.8.0-rc4-syzkaller-01028-g71b605d32017 #0
+Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
+Workqueue: events_unbound __unix_gc
+RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:200
+Code: 89 fb e8 23 00 00 00 48 8b 3d 84 f5 1a 0c 48 89 de 5b e9 43 26 57 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 48 8b 04 24 65 48 8b 0d 90 52 70 7e 65 8b 15 91 52 70
+RSP: 0018:ffffc9000a17fa78 EFLAGS: 00000287
+RAX: ffffffff8a0a6108 RBX: ffff88802b6c2640 RCX: ffff88802c0b3b80
+RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
+RBP: ffffc9000a17fbf0 R08: ffffffff89383f1d R09: 1ffff1100ee5ff84
+R10: dffffc0000000000 R11: ffffed100ee5ff85 R12: 1ffff110056d84ee
+R13: ffffc9000a17fae0 R14: 0000000000000000 R15: ffffffff8f47b840
+FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
+CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
+CR2: 00007ffef5687ff8 CR3: 0000000029b34000 CR4: 00000000003506f0
+DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
+DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
+Call Trace:
+ <NMI>
+ </NMI>
+ <TASK>
+ __unix_gc+0xe69/0xf40 net/unix/garbage.c:343
+ process_one_work kernel/workqueue.c:2633 [inline]
+ process_scheduled_works+0x913/0x1420 kernel/workqueue.c:2706
+ worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787
+ kthread+0x2ef/0x390 kernel/kthread.c:388
+ ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
+ ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
+ </TASK>
+
+Reported-and-tested-by: syzbot+ecab4d36f920c3574bf9@syzkaller.appspotmail.com
+Closes: https://syzkaller.appspot.com/bug?extid=ecab4d36f920c3574bf9
+Fixes: 25236c91b5ab ("af_unix: Fix task hung while purging oob_skb in GC.")
+Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ net/unix/garbage.c |   22 +++++++++-------------
+ 1 file changed, 9 insertions(+), 13 deletions(-)
+
+--- a/net/unix/garbage.c
++++ b/net/unix/garbage.c
+@@ -284,9 +284,17 @@ void unix_gc(void)
+        * which are creating the cycle(s).
+        */
+       skb_queue_head_init(&hitlist);
+-      list_for_each_entry(u, &gc_candidates, link)
++      list_for_each_entry(u, &gc_candidates, link) {
+               scan_children(&u->sk, inc_inflight, &hitlist);
+ 
++#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
++              if (u->oob_skb) {
++                      kfree_skb(u->oob_skb);
++                      u->oob_skb = NULL;
++              }
++#endif
++      }
++
+       /* not_cycle_list contains those sockets which do not make up a
+        * cycle.  Restore these to the inflight list.
+        */
+@@ -314,18 +322,6 @@ void unix_gc(void)
+       /* Here we are. Hitlist is filled. Die. */
+       __skb_queue_purge(&hitlist);
+ 
+-#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
+-      while (!list_empty(&gc_candidates)) {
+-              u = list_entry(gc_candidates.next, struct unix_sock, link);
+-              if (u->oob_skb) {
+-                      struct sk_buff *skb = u->oob_skb;
+-
+-                      u->oob_skb = NULL;
+-                      kfree_skb(skb);
+-              }
+-      }
+-#endif
+-
+       spin_lock(&unix_gc_lock);
+ 
+       /* There could be io_uring registered files, just push them back to

diff --git a/queue-5.15/series b/queue-5.15/series
index fdb52ce6142d89435774157f803f6e85d3cf6e01..d8cb3a303f8ad94185a0656f6388ee27ec4a0602 100644 (file)
--- a/queue-5.15/series
+++ b/queue-5.15/series
@@ -71,3 +71,4 @@ mptcp-fix-possible-deadlock-in-subflow-diag.patch
 cachefiles-fix-memory-leak-in-cachefiles_add_cache.patch
 fs-hugetlb-fix-null-pointer-dereference-in-hugetlbs_fill_super.patch
 revert-drm-bridge-lt8912b-register-and-attach-our-dsi-device-at-probe.patch
+af_unix-drop-oob_skb-ref-before-purging-queue-in-gc.patch