------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 7316 at lib/refcount.c:28 refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28
Modules linked in:
CPU: 1 UID: 0 PID: 7316 Comm: syz.0.170 Not tainted 6.12.0-syzkaller-g7b1d1d4cfac0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28
lr : refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28
sp : ffff8000a21f7990
x29: ffff8000a21f7990 x28: 0000000000000001 x27: 00000000ffffffff
x26: 1fffe00018610118 x25: dfff800000000000 x24: 0000000000000000
x23: ffff0000f11d95e4 x22: ffff80008a63b670 x21: 0000000000000003
x20: ffff0000f11d95e4 x19: ffff800092b74000 x18: 0000000000000008
x17: 0000000000000000 x16: ffff8000831615b0 x15: 0000000000000001
x14: 1fffe000366c80e2 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000080000 x10: 0000000000001a71 x9 : 1d23518fabfe1700
x8 : 1d23518fabfe1700 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000a21f70b8 x4 : ffff80008f9bd220 x3 : ffff800080626d8c
x2 : 0000000000000001 x1 : 0000000000000201 x0 : 0000000000000000
Call trace:
 refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28 (P)
 refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28 (L)
 __refcount_sub_and_test include/linux/refcount.h:275 [inline]
 __refcount_dec_and_test include/linux/refcount.h:307 [inline]
 refcount_dec_and_test include/linux/refcount.h:325 [inline]
 skb_unref include/linux/skbuff.h:1232 [inline]
 __sk_skb_reason_drop net/core/skbuff.c:1213 [inline]
 sk_skb_reason_drop+0x210/0x43c net/core/skbuff.c:1241
 kfree_skb_reason include/linux/skbuff.h:1262 [inline]
 kfree_skb include/linux/skbuff.h:1271 [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+0x1c8/0x460 net/can/j1939/transport.c:299
 j1939_sk_queue_drop_all+0x15c/0x210 net/can/j1939/socket.c:144
 j1939_sk_release+0x264/0x5f0 net/can/j1939/socket.c:642
 __sock_release net/socket.c:658 [inline]
 sock_close+0xa4/0x1e8 net/socket.c:1426
 __fput+0x1bc/0x75c fs/file_table.c:431
 ____fput+0x20/0x30 fs/file_table.c:459
 task_work_run+0x230/0x2e0 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 do_notify_resume+0x178/0x1f4 arch/arm64/kernel/entry-common.c:151
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
 el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:745
 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
irq event stamp: 2727
hardirqs last  enabled at (2726): [<ffff80008039a9c4>] __up_console_sem kernel/printk/printk.c:344 [inline]
hardirqs last  enabled at (2726): [<ffff80008039a9c4>] __console_unlock+0x70/0xc4 kernel/printk/printk.c:2844
hardirqs last disabled at (2727): [<ffff80008b54386c>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:488
softirqs last  enabled at (2698): [<ffff80008a63ea6c>] spin_unlock_bh include/linux/spinlock.h:396 [inline]
softirqs last  enabled at (2698): [<ffff80008a63ea6c>] j1939_session_list_unlock net/can/j1939/transport.c:243 [inline]
softirqs last  enabled at (2698): [<ffff80008a63ea6c>] j1939_cancel_active_session+0x3a0/0x414 net/can/j1939/transport.c:2214
softirqs last disabled at (2700): [<ffff80008a636aa8>] spin_lock_bh include/linux/spinlock.h:356 [inline]
softirqs last disabled at (2700): [<ffff80008a636aa8>] j1939_sk_queue_drop_all+0x50/0x210 net/can/j1939/socket.c:139
---[ end trace 0000000000000000 ]---