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authorEric Dumazet2023-07-20 11:44:38 +0000
committerMarc Kleine-Budde2023-07-20 13:46:29 +0200
commit11c9027c983e9e4b408ee5613b6504d24ebd85be (patch)
tree2ed5e8401ffd9483965a4579e7bcb477cc382a91 /net
parentf8a2da6ec2417cca169fa85a8ab15817bccbb109 (diff)
can: raw: fix lockdep issue in raw_release()
syzbot complained about a lockdep issue [1] Since raw_bind() and raw_setsockopt() first get RTNL before locking the socket, we must adopt the same order in raw_release() [1] WARNING: possible circular locking dependency detected 6.5.0-rc1-syzkaller-00192-g78adb4bcf99e #0 Not tainted ------------------------------------------------------ syz-executor.0/14110 is trying to acquire lock: ffff88804e4b6130 (sk_lock-AF_CAN){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1708 [inline] ffff88804e4b6130 (sk_lock-AF_CAN){+.+.}-{0:0}, at: raw_bind+0xb1/0xab0 net/can/raw.c:435 but task is already holding lock: ffffffff8e3df368 (rtnl_mutex){+.+.}-{3:3}, at: raw_bind+0xa7/0xab0 net/can/raw.c:434 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (rtnl_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x181/0x1340 kernel/locking/mutex.c:747 raw_release+0x1c6/0x9b0 net/can/raw.c:391 __sock_release+0xcd/0x290 net/socket.c:654 sock_close+0x1c/0x20 net/socket.c:1386 __fput+0x3fd/0xac0 fs/file_table.c:384 task_work_run+0x14d/0x240 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x210/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 do_syscall_64+0x44/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (sk_lock-AF_CAN){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3142 [inline] check_prevs_add kernel/locking/lockdep.c:3261 [inline] validate_chain kernel/locking/lockdep.c:3876 [inline] __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5144 lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 lock_sock_nested+0x3a/0xf0 net/core/sock.c:3492 lock_sock include/net/sock.h:1708 [inline] raw_bind+0xb1/0xab0 net/can/raw.c:435 __sys_bind+0x1ec/0x220 net/socket.c:1792 __do_sys_bind net/socket.c:1803 [inline] __se_sys_bind net/socket.c:1801 [inline] __x64_sys_bind+0x72/0xb0 net/socket.c:1801 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock(sk_lock-AF_CAN); lock(rtnl_mutex); lock(sk_lock-AF_CAN); *** DEADLOCK *** 1 lock held by syz-executor.0/14110: stack backtrace: CPU: 0 PID: 14110 Comm: syz-executor.0 Not tainted 6.5.0-rc1-syzkaller-00192-g78adb4bcf99e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 check_noncircular+0x311/0x3f0 kernel/locking/lockdep.c:2195 check_prev_add kernel/locking/lockdep.c:3142 [inline] check_prevs_add kernel/locking/lockdep.c:3261 [inline] validate_chain kernel/locking/lockdep.c:3876 [inline] __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5144 lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 lock_sock_nested+0x3a/0xf0 net/core/sock.c:3492 lock_sock include/net/sock.h:1708 [inline] raw_bind+0xb1/0xab0 net/can/raw.c:435 __sys_bind+0x1ec/0x220 net/socket.c:1792 __do_sys_bind net/socket.c:1803 [inline] __se_sys_bind net/socket.c:1801 [inline] __x64_sys_bind+0x72/0xb0 net/socket.c:1801 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fd89007cb29 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:00007fd890d2a0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000031 RAX: ffffffffffffffda RBX: 00007fd89019bf80 RCX: 00007fd89007cb29 RDX: 0000000000000010 RSI: 0000000020000040 RDI: 0000000000000003 RBP: 00007fd8900c847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fd89019bf80 R15: 00007ffebf8124f8 </TASK> Fixes: ee8b94c8510c ("can: raw: fix receiver memory leak") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Ziyang Xuan <william.xuanziyang@huawei.com> Cc: Oliver Hartkopp <socketcan@hartkopp.net> Cc: stable@vger.kernel.org Cc: Marc Kleine-Budde <mkl@pengutronix.de> Link: https://lore.kernel.org/all/20230720114438.172434-1-edumazet@google.com Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'net')
-rw-r--r--net/can/raw.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/net/can/raw.c b/net/can/raw.c
index 2302e4882967..ba6b52b1d776 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -386,9 +386,9 @@ static int raw_release(struct socket *sock)
list_del(&ro->notifier);
spin_unlock(&raw_notifier_lock);
+ rtnl_lock();
lock_sock(sk);
- rtnl_lock();
/* remove current filters & unregister */
if (ro->bound) {
if (ro->dev)
@@ -405,12 +405,13 @@ static int raw_release(struct socket *sock)
ro->dev = NULL;
ro->count = 0;
free_percpu(ro->uniq);
- rtnl_unlock();
sock_orphan(sk);
sock->sk = NULL;
release_sock(sk);
+ rtnl_unlock();
+
sock_put(sk);
return 0;