loop0: detected capacity change from 0 to 40427 F2FS-fs (loop0): build fault injection attr: rate: 0, type: 0x7 F2FS-fs (loop0): invalid crc value F2FS-fs (loop0): Found nat_bits in checkpoint F2FS-fs (loop0): Start checkpoint disabled! F2FS-fs (loop0): Mounted with checkpoint version = 48b305e6 ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 5314 at lib/refcount.c:28 refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 Modules linked in: CPU: 0 UID: 0 PID: 5314 Comm: syz.0.0 Not tainted 6.13.0-rc1-syzkaller-00036-g5076001689e4 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 Code: e0 1e 5f 8c e8 87 c5 95 fc 90 0f 0b 90 90 eb 99 e8 2b 1e d5 fc c6 05 2d 2c 39 0b 01 90 48 c7 c7 40 1f 5f 8c e8 67 c5 95 fc 90 <0f> 0b 90 90 e9 76 ff ff ff e8 08 1e d5 fc c6 05 07 2c 39 0b 01 90 RSP: 0018:ffffc9000d547668 EFLAGS: 00010246 RAX: 8cad1ecf70fb1800 RBX: ffff888051c730e4 RCX: 0000000000100000 RDX: ffffc9000ed41000 RSI: 00000000000009fa RDI: 00000000000009fb RBP: 0000000000000003 R08: ffffffff81601c02 R09: 1ffff11003f8519a R10: dffffc0000000000 R11: ffffed1003f8519b R12: ffff888040592c68 R13: ffff888051c730e4 R14: 1ffff110080b2598 R15: ffff888040592c00 FS: 00007f247e7c46c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020001980 CR3: 000000004110e000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kfree_skb_reason include/linux/skbuff.h:1263 [inline] kfree_skb include/linux/skbuff.h:1272 [inline] j1939_session_destroy net/can/j1939/transport.c:282 [inline] __j1939_session_release net/can/j1939/transport.c:294 [inline] kref_put include/linux/kref.h:65 [inline] j1939_session_put+0x1ed/0x440 net/can/j1939/transport.c:299 j1939_sk_send_loop net/can/j1939/socket.c:1202 [inline] j1939_sk_sendmsg+0x121b/0x14c0 net/can/j1939/socket.c:1277 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:726 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2583 ___sys_sendmsg net/socket.c:2637 [inline] __sys_sendmmsg+0x36a/0x720 net/socket.c:2726 __do_sys_sendmmsg net/socket.c:2753 [inline] __se_sys_sendmmsg net/socket.c:2750 [inline] __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2750 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f247d97ff19 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f247e7c4058 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f247db45fa0 RCX: 00007f247d97ff19 RDX: 0000000000000002 RSI: 00000000200038c0 RDI: 0000000000000003 RBP: 00007f247d9f3986 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000080 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f247db45fa0 R15: 00007fff596f64c8