4.19-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit 64b8bc7d5f1434c636a40bdcfcd42b278d1714be ]
syzbot found an interesting netdev refcounting issue in net/rose/af_rose.c, thanks to CONFIG_NET_DEV_REFCNT_TRACKER=y [1]
Problem is that rose_kill_by_device() can change rose->device while other threads do not expect the pointer to be changed.
We have to first collect sockets in a temporary array, then perform the changes while holding the socket lock and rose_list_lock spinlock (in this order)
Change rose_release() to also acquire rose_list_lock before releasing the netdev refcount.
[1]
[ 1185.055088][ T7889] ref_tracker: reference already released. [ 1185.061476][ T7889] ref_tracker: allocated in: [ 1185.066081][ T7889] rose_bind+0x4ab/0xd10 [ 1185.070446][ T7889] __sys_bind+0x1ec/0x220 [ 1185.074818][ T7889] __x64_sys_bind+0x72/0xb0 [ 1185.079356][ T7889] do_syscall_64+0x40/0x110 [ 1185.083897][ T7889] entry_SYSCALL_64_after_hwframe+0x63/0x6b [ 1185.089835][ T7889] ref_tracker: freed in: [ 1185.094088][ T7889] rose_release+0x2f5/0x570 [ 1185.098629][ T7889] __sock_release+0xae/0x260 [ 1185.103262][ T7889] sock_close+0x1c/0x20 [ 1185.107453][ T7889] __fput+0x270/0xbb0 [ 1185.111467][ T7889] task_work_run+0x14d/0x240 [ 1185.116085][ T7889] get_signal+0x106f/0x2790 [ 1185.120622][ T7889] arch_do_signal_or_restart+0x90/0x7f0 [ 1185.126205][ T7889] exit_to_user_mode_prepare+0x121/0x240 [ 1185.131846][ T7889] syscall_exit_to_user_mode+0x1e/0x60 [ 1185.137293][ T7889] do_syscall_64+0x4d/0x110 [ 1185.141783][ T7889] entry_SYSCALL_64_after_hwframe+0x63/0x6b [ 1185.148085][ T7889] ------------[ cut here ]------------
WARNING: CPU: 1 PID: 7889 at lib/ref_tracker.c:255 ref_tracker_free+0x61a/0x810 lib/ref_tracker.c:255 Modules linked in: CPU: 1 PID: 7889 Comm: syz-executor.2 Not tainted 6.7.0-rc4-syzkaller-00162-g65c95f78917e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 RIP: 0010:ref_tracker_free+0x61a/0x810 lib/ref_tracker.c:255 Code: 00 44 8b 6b 18 31 ff 44 89 ee e8 21 62 f5 fc 45 85 ed 0f 85 a6 00 00 00 e8 a3 66 f5 fc 48 8b 34 24 48 89 ef e8 27 5f f1 05 90 <0f> 0b 90 bb ea ff ff ff e9 52 fd ff ff e8 84 66 f5 fc 4c 8d 6d 44 RSP: 0018:ffffc90004917850 EFLAGS: 00010202 RAX: 0000000000000201 RBX: ffff88802618f4c0 RCX: 0000000000000000 RDX: 0000000000000202 RSI: ffffffff8accb920 RDI: 0000000000000001 RBP: ffff8880269ea5b8 R08: 0000000000000001 R09: fffffbfff23e35f6 R10: ffffffff91f1afb7 R11: 0000000000000001 R12: 1ffff92000922f0c R13: 0000000005a2039b R14: ffff88802618f4d8 R15: 00000000ffffffff FS: 00007f0a720ef6c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f43a819d988 CR3: 0000000076c64000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> netdev_tracker_free include/linux/netdevice.h:4127 [inline] netdev_put include/linux/netdevice.h:4144 [inline] netdev_put include/linux/netdevice.h:4140 [inline] rose_kill_by_device net/rose/af_rose.c:195 [inline] rose_device_event+0x25d/0x330 net/rose/af_rose.c:218 notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93 call_netdevice_notifiers_info+0xbe/0x130 net/core/dev.c:1967 call_netdevice_notifiers_extack net/core/dev.c:2005 [inline] call_netdevice_notifiers net/core/dev.c:2019 [inline] __dev_notify_flags+0x1f5/0x2e0 net/core/dev.c:8646 dev_change_flags+0x122/0x170 net/core/dev.c:8682 dev_ifsioc+0x9ad/0x1090 net/core/dev_ioctl.c:529 dev_ioctl+0x224/0x1090 net/core/dev_ioctl.c:786 sock_do_ioctl+0x198/0x270 net/socket.c:1234 sock_ioctl+0x22e/0x6b0 net/socket.c:1339 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl fs/ioctl.c:857 [inline] __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f0a7147cba9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0a720ef0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f0a7159bf80 RCX: 00007f0a7147cba9 RDX: 0000000020000040 RSI: 0000000000008914 RDI: 0000000000000004 RBP: 00007f0a714c847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f0a7159bf80 R15: 00007ffc8bb3a5f8 </TASK>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: Eric Dumazet edumazet@google.com Cc: Bernard Pidoux f6bvp@free.fr Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/rose/af_rose.c | 39 ++++++++++++++++++++++++++++++++++----- 1 file changed, 34 insertions(+), 5 deletions(-)
diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c index d32fb40650a75..015e475f5554b 100644 --- a/net/rose/af_rose.c +++ b/net/rose/af_rose.c @@ -184,21 +184,47 @@ void rose_kill_by_neigh(struct rose_neigh *neigh) */ static void rose_kill_by_device(struct net_device *dev) { - struct sock *s; + struct sock *sk, *array[16]; + struct rose_sock *rose; + bool rescan; + int i, cnt;
+start: + rescan = false; + cnt = 0; spin_lock_bh(&rose_list_lock); - sk_for_each(s, &rose_list) { - struct rose_sock *rose = rose_sk(s); + sk_for_each(sk, &rose_list) { + rose = rose_sk(sk); + if (rose->device == dev) { + if (cnt == ARRAY_SIZE(array)) { + rescan = true; + break; + } + sock_hold(sk); + array[cnt++] = sk; + } + } + spin_unlock_bh(&rose_list_lock);
+ for (i = 0; i < cnt; i++) { + sk = array[cnt]; + rose = rose_sk(sk); + lock_sock(sk); + spin_lock_bh(&rose_list_lock); if (rose->device == dev) { - rose_disconnect(s, ENETUNREACH, ROSE_OUT_OF_ORDER, 0); + rose_disconnect(sk, ENETUNREACH, ROSE_OUT_OF_ORDER, 0); if (rose->neighbour) rose->neighbour->use--; dev_put(rose->device); rose->device = NULL; } + spin_unlock_bh(&rose_list_lock); + release_sock(sk); + sock_put(sk); + cond_resched(); } - spin_unlock_bh(&rose_list_lock); + if (rescan) + goto start; }
/* @@ -658,7 +684,10 @@ static int rose_release(struct socket *sock) break; }
+ spin_lock_bh(&rose_list_lock); dev_put(rose->device); + rose->device = NULL; + spin_unlock_bh(&rose_list_lock); sock->sk = NULL; release_sock(sk); sock_put(sk);