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charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot found the following issue on: HEAD commit: 3bdc70669eb2 Merge branch 'devlink-register' git tree: net-next console output: https://syzkaller.appspot.com/x/log.txt?x=11ee370a300000 kernel config: https://syzkaller.appspot.com/x/.config?x=914a8107c0ffdc14 dashboard link: https://syzkaller.appspot.com/bug?extid=34fe5894623c4ab1b379 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=114398c6300000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10d6d61a300000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+34fe5894623c4ab1b379@syzkaller.appspotmail.com netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0 ====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc2-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor772/8460 is trying to acquire lock: ffffffff8d0a9608 (br_ioctl_mutex){+.+.}-{3:3}, at: br_ioctl_call+0x3b/0xa0 net/socket.c:1089 but task is already holding lock: ffffffff8d0cb568 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x1a7/0xee0 net/core/dev_ioctl.c:579 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:959 [inline] __mutex_lock+0x12a/0x10a0 kernel/locking/mutex.c:1104 register_netdev+0x11/0x50 net/core/dev.c:10474 br_add_bridge+0x97/0xf0 net/bridge/br_if.c:459 br_ioctl_stub+0x750/0x7f0 net/bridge/br_ioctl.c:390 br_ioctl_call+0x5e/0xa0 net/socket.c:1091 sock_ioctl+0x30c/0x640 net/socket.c:1185 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl fs/ioctl.c:1055 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (br_ioctl_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __mutex_lock_common kernel/locking/mutex.c:959 [inline] __mutex_lock+0x12a/0x10a0 kernel/locking/mutex.c:1104 br_ioctl_call+0x3b/0xa0 net/socket.c:1089 dev_ifsioc+0xc1f/0xf60 net/core/dev_ioctl.c:382 dev_ioctl+0x1b9/0xee0 net/core/dev_ioctl.c:580 sock_do_ioctl+0x18b/0x210 net/socket.c:1128 sock_ioctl+0x2f1/0x640 net/socket.c:1231 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl fs/ioctl.c:1055 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock(br_ioctl_mutex); lock(rtnl_mutex); lock(br_ioctl_mutex); *** DEADLOCK *** 1 lock held by syz-executor772/8460: #0: ffffffff8d0cb568 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x1a7/0xee0 net/core/dev_ioctl.c:579 stack backtrace: CPU: 0 PID: 8460 Comm: syz-executor772 Not tainted 5.14.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2131 check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __mutex_lock_common kernel/locking/mutex.c:959 [inline] __mutex_lock+0x12a/0x10a0 kernel/locking/mutex.c:1104 br_ioctl_call+0x3b/0xa0 net/socket.c:1089 dev_ifsioc+0xc1f/0xf60 net/core/dev_ioctl.c:382 dev_ioctl+0x1b9/0xee0 net/core/dev_ioctl.c:580 sock_do_ioctl+0x18b/0x210 net/socket.c:1128 sock_ioctl+0x2f1/0x640 net/socket.c:1231 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl fs/ioctl.c:1055 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4431f9 Code: 28 c3 e8 4a 15 00 00 66 2e 0f 1f 84 00 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd0ab19648 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffd0ab19658 RCX: 00000000004431f9 RDX: 0000000020000000 RSI: 00000000000089a2 RDI: 0000000000000004 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd0ab19660 R13 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches