------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 0 PID: 340 at lib/refcount.c:25 refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 Modules linked in: CPU: 0 PID: 340 Comm: kworker/u4:4 Not tainted 5.15.185-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: writeback wb_workfn (flush-259:0) pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 lr : refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 sp : ffff800008007800 x29: ffff800008007800 x28: ffff0000d5d8e800 x27: ffff0000cda20200 x26: 1fffe0001900d001 x25: dfff800000000000 x24: 1fffe00019b44041 x23: ffff0000e8f0c000 x22: ffff0000c1e23654 x21: ffff0000db90d880 x20: ffff0000c1e23654 x19: ffff80001659e000 x18: 0000000000000101 x17: 0000000000000000 x16: ffff8000111a97c4 x15: 00000000ffffffff x14: 0000000000ff0100 x13: 0000000000000001 x12: 0000000000ff0100 x11: 0000000000000100 x10: 0000000000000000 x9 : 8863a9ea98622a00 x8 : 8863a9ea98622a00 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff8000080070f8 x4 : ffff80001423f280 x3 : ffff800008503958 x2 : 0000000000000001 x1 : 0000000000000100 x0 : 000000000000002a Call trace: refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] get_net include/net/net_namespace.h:252 [inline] tipc_aead_encrypt net/tipc/crypto.c:832 [inline] tipc_crypto_xmit+0x1634/0x2220 net/tipc/crypto.c:1772 tipc_bearer_xmit_skb+0x1f0/0x384 net/tipc/bearer.c:574 tipc_disc_timeout+0x4c8/0x608 net/tipc/discover.c:338 call_timer_fn+0x19c/0x858 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x46c/0x6c4 kernel/time/timer.c:1767 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1780 handle_softirqs+0x344/0xbf0 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline] invoke_softirq kernel/softirq.c:457 [inline] __irq_exit_rcu+0x240/0x440 kernel/softirq.c:659 irq_exit+0x14/0x88 kernel/softirq.c:683 handle_domain_irq+0x14c/0x1fc kernel/irq/irqdesc.c:711 gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:765 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:899 do_interrupt_handler+0x6c/0x88 arch/arm64/kernel/entry-common.c:267 el1_interrupt+0x30/0x58 arch/arm64/kernel/entry-common.c:454 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522 __preempt_count_add arch/arm64/include/asm/preempt.h:46 [inline] rcu_is_watching+0x40/0x134 kernel/rcu/tree.c:1122 rcu_read_lock_held_common kernel/rcu/update.c:108 [inline] rcu_read_lock_held+0x18/0x50 kernel/rcu/update.c:309 xa_entry include/linux/xarray.h:1182 [inline] xas_reload+0x18c/0x448 include/linux/xarray.h:1558 find_get_entry+0x1bc/0x254 mm/filemap.c:1996 find_get_pages_range_tag+0x190/0x3fc mm/filemap.c:2272 pagevec_lookup_range_tag+0x4c/0xa4 mm/swap.c:1114 mpage_prepare_extent_to_map+0x2a0/0xda4 fs/ext4/inode.c:2590 ext4_writepages+0xb78/0x2c14 fs/ext4/inode.c:2827 do_writepages+0x36c/0x578 mm/page-writeback.c:2386 __writeback_single_inode+0x148/0x11f0 fs/fs-writeback.c:1647 writeback_sb_inodes+0x7fc/0x1378 fs/fs-writeback.c:1930 __writeback_inodes_wb+0x110/0x394 fs/fs-writeback.c:2001 wb_writeback+0x3ec/0xe44 fs/fs-writeback.c:2106 wb_check_old_data_flush fs/fs-writeback.c:2206 [inline] wb_do_writeback fs/fs-writeback.c:2259 [inline] wb_workfn+0xa18/0xdd8 fs/fs-writeback.c:2288 process_one_work+0x79c/0x1140 kernel/workqueue.c:2310 worker_thread+0x8f4/0x101c kernel/workqueue.c:2457 kthread+0x374/0x454 kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870 irq event stamp: 893345 hardirqs last enabled at (893344): [] __up_console_sem+0xb4/0x100 kernel/printk/printk.c:257 hardirqs last disabled at (893345): [] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:396 softirqs last enabled at (892930): [] softirq_handle_end kernel/softirq.c:419 [inline] softirqs last enabled at (892930): [] handle_softirqs+0xa4c/0xbf0 kernel/softirq.c:604 softirqs last disabled at (893315): [] __do_softirq kernel/softirq.c:610 [inline] softirqs last disabled at (893315): [] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline] softirqs last disabled at (893315): [] invoke_softirq kernel/softirq.c:457 [inline] softirqs last disabled at (893315): [] __irq_exit_rcu+0x240/0x440 kernel/softirq.c:659 ---[ end trace fe9d40fb68e31659 ]--- ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 340 at lib/refcount.c:28 refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 Modules linked in: CPU: 0 PID: 340 Comm: kworker/u4:4 Tainted: G W 5.15.185-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: writeback wb_workfn (flush-259:0) pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 lr : refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 sp : ffff800008007800 x29: ffff800008007800 x28: ffff0000d5d8e800 x27: 0000000000000000 x26: 1fffe0001900d001 x25: dfff800000000000 x24: 1fffe00019b44041 x23: ffff0000cffe72b8 x22: ffff0000c1e23500 x21: ffff0000db90d880 x20: ffff0000c1e23654 x19: ffff80001659e000 x18: 0000000000000101 x17: 0000000000000000 x16: ffff8000111a97c4 x15: 00000000ffffffff x14: 0000000000ff0100 x13: 0000000000000001 x12: 0000000000ff0100 x11: 0000000000000100 x10: 0000000000000000 x9 : 8863a9ea98622a00 x8 : 8863a9ea98622a00 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff8000080070f8 x4 : ffff80001423f280 x3 : ffff800008503958 x2 : 0000000000000001 x1 : 0000000000000100 x0 : 0000000000000026 Call trace: refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 __refcount_sub_and_test include/linux/refcount.h:283 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] put_net include/net/net_namespace.h:270 [inline] tipc_aead_encrypt net/tipc/crypto.c:840 [inline] tipc_crypto_xmit+0x177c/0x2220 net/tipc/crypto.c:1772 tipc_bearer_xmit_skb+0x1f0/0x384 net/tipc/bearer.c:574 tipc_disc_timeout+0x4c8/0x608 net/tipc/discover.c:338 call_timer_fn+0x19c/0x858 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x46c/0x6c4 kernel/time/timer.c:1767 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1780 handle_softirqs+0x344/0xbf0 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline] invoke_softirq kernel/softirq.c:457 [inline] __irq_exit_rcu+0x240/0x440 kernel/softirq.c:659 irq_exit+0x14/0x88 kernel/softirq.c:683 handle_domain_irq+0x14c/0x1fc kernel/irq/irqdesc.c:711 gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:765 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:899 do_interrupt_handler+0x6c/0x88 arch/arm64/kernel/entry-common.c:267 el1_interrupt+0x30/0x58 arch/arm64/kernel/entry-common.c:454 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522 __preempt_count_add arch/arm64/include/asm/preempt.h:46 [inline] rcu_is_watching+0x40/0x134 kernel/rcu/tree.c:1122 rcu_read_lock_held_common kernel/rcu/update.c:108 [inline] rcu_read_lock_held+0x18/0x50 kernel/rcu/update.c:309 xa_entry include/linux/xarray.h:1182 [inline] xas_reload+0x18c/0x448 include/linux/xarray.h:1558 find_get_entry+0x1bc/0x254 mm/filemap.c:1996 find_get_pages_range_tag+0x190/0x3fc mm/filemap.c:2272 pagevec_lookup_range_tag+0x4c/0xa4 mm/swap.c:1114 mpage_prepare_extent_to_map+0x2a0/0xda4 fs/ext4/inode.c:2590 ext4_writepages+0xb78/0x2c14 fs/ext4/inode.c:2827 do_writepages+0x36c/0x578 mm/page-writeback.c:2386 __writeback_single_inode+0x148/0x11f0 fs/fs-writeback.c:1647 writeback_sb_inodes+0x7fc/0x1378 fs/fs-writeback.c:1930 __writeback_inodes_wb+0x110/0x394 fs/fs-writeback.c:2001 wb_writeback+0x3ec/0xe44 fs/fs-writeback.c:2106 wb_check_old_data_flush fs/fs-writeback.c:2206 [inline] wb_do_writeback fs/fs-writeback.c:2259 [inline] wb_workfn+0xa18/0xdd8 fs/fs-writeback.c:2288 process_one_work+0x79c/0x1140 kernel/workqueue.c:2310 worker_thread+0x8f4/0x101c kernel/workqueue.c:2457 kthread+0x374/0x454 kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870 irq event stamp: 893373 hardirqs last enabled at (893372): [] __up_console_sem+0xb4/0x100 kernel/printk/printk.c:257 hardirqs last disabled at (893373): [] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:396 softirqs last enabled at (892930): [] softirq_handle_end kernel/softirq.c:419 [inline] softirqs last enabled at (892930): [] handle_softirqs+0xa4c/0xbf0 kernel/softirq.c:604 softirqs last disabled at (893315): [] __do_softirq kernel/softirq.c:610 [inline] softirqs last disabled at (893315): [] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline] softirqs last disabled at (893315): [] invoke_softirq kernel/softirq.c:457 [inline] softirqs last disabled at (893315): [] __irq_exit_rcu+0x240/0x440 kernel/softirq.c:659 ---[ end trace fe9d40fb68e3165a ]--- ------------[ cut here ]------------ refcount_t: saturated; leaking memory. WARNING: CPU: 0 PID: 4036 at lib/refcount.c:22 refcount_warn_saturate+0x1b4/0x1f8 lib/refcount.c:22 Modules linked in: CPU: 0 PID: 4036 Comm: syz-executor Tainted: G W 5.15.185-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0x1b4/0x1f8 lib/refcount.c:22 lr : refcount_warn_saturate+0x1b4/0x1f8 lib/refcount.c:22 sp : ffff800008007800 x29: ffff800008007800 x28: ffff0000e8168400 x27: ffff0000cda20200 x26: 1fffe0001ca34001 x25: dfff800000000000 x24: 1fffe00019b44041 x23: ffff0000e8f0c000 x22: ffff0000c1e23654 x21: 000000007ffffffe x20: ffff0000c1e23654 x19: ffff80001659e000 x18: 0000000000000101 x17: 0000000000000000 x16: ffff8000111a97c4 x15: 00000000ffffffff x14: 0000000000ff0100 x13: 0000000000000001 x12: 0000000000ff0100 x11: 0000000000000100 x10: 0000000000000000 x9 : 110b988f40851500 x8 : 110b988f40851500 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff8000080070f8 x4 : ffff80001423f280 x3 : ffff800008503958 x2 : 0000000000000001 x1 : 0000000100000100 x0 : 0000000000000026 Call trace: refcount_warn_saturate+0x1b4/0x1f8 lib/refcount.c:22 __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] get_net include/net/net_namespace.h:252 [inline] tipc_aead_encrypt net/tipc/crypto.c:832 [inline] tipc_crypto_xmit+0x1634/0x2220 net/tipc/crypto.c:1772 tipc_bearer_xmit_skb+0x1f0/0x384 net/tipc/bearer.c:574 tipc_disc_timeout+0x4c8/0x608 net/tipc/discover.c:338 call_timer_fn+0x19c/0x858 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x46c/0x6c4 kernel/time/timer.c:1767 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1780 handle_softirqs+0x344/0xbf0 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline] invoke_softirq kernel/softirq.c:457 [inline] __irq_exit_rcu+0x240/0x440 kernel/softirq.c:659 irq_exit+0x14/0x88 kernel/softirq.c:683 handle_domain_irq+0x14c/0x1fc kernel/irq/irqdesc.c:711 gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:765 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:899 do_interrupt_handler+0x6c/0x88 arch/arm64/kernel/entry-common.c:267 el1_interrupt+0x30/0x58 arch/arm64/kernel/entry-common.c:454 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522 netlink_trim+0x160/0x204 net/netlink/af_netlink.c:1293 netlink_broadcast_filtered+0x7c/0xe64 net/netlink/af_netlink.c:1498 netlink_broadcast net/netlink/af_netlink.c:1543 [inline] nlmsg_multicast include/net/netlink.h:1033 [inline] nlmsg_notify+0x100/0x1f0 net/netlink/af_netlink.c:2532 rtnl_notify+0xa0/0xd8 net/core/rtnetlink.c:759 inet_netconf_notify_devconf+0x1f0/0x25c net/ipv4/devinet.c:2134 __devinet_sysctl_unregister net/ipv4/devinet.c:2631 [inline] devinet_sysctl_unregister net/ipv4/devinet.c:2655 [inline] inetdev_destroy net/ipv4/devinet.c:326 [inline] inetdev_event+0x5a0/0x127c net/ipv4/devinet.c:1612 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2049 [inline] call_netdevice_notifiers_extack net/core/dev.c:2061 [inline] call_netdevice_notifiers net/core/dev.c:2075 [inline] unregister_netdevice_many+0xe10/0x17d0 net/core/dev.c:11134 unregister_netdevice_queue+0x2ac/0x2f8 net/core/dev.c:11067 unregister_netdevice include/linux/netdevice.h:3020 [inline] __tun_detach+0xb14/0x126c drivers/net/tun.c:686 tun_detach drivers/net/tun.c:702 [inline] tun_chr_close+0x118/0x20c drivers/net/tun.c:3440 __fput+0x1c0/0x7f8 fs/file_table.c:311 ____fput+0x20/0x30 fs/file_table.c:339 task_work_run+0x12c/0x1e0 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x67c/0x1f58 kernel/exit.c:874 do_group_exit+0x100/0x268 kernel/exit.c:996 get_signal+0x73c/0x1340 kernel/signal.c:2900 do_signal arch/arm64/kernel/signal.c:893 [inline] do_notify_resume+0x35c/0x3128 arch/arm64/kernel/signal.c:946 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline] el0_svc+0xf0/0x1e0 arch/arm64/kernel/entry-common.c:609 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 irq event stamp: 463087 hardirqs last enabled at (463086): [] __up_console_sem+0xb4/0x100 kernel/printk/printk.c:257 hardirqs last disabled at (463087): [] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:396 softirqs last enabled at (463026): [] spin_unlock_bh include/linux/spinlock.h:408 [inline] softirqs last enabled at (463026): [] sctp_inetaddr_event+0x41c/0x4b8 net/sctp/protocol.c:813 softirqs last disabled at (463063): [] __do_softirq kernel/softirq.c:610 [inline] softirqs last disabled at (463063): [] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline] softirqs last disabled at (463063): [] invoke_softirq kernel/softirq.c:457 [inline] softirqs last disabled at (463063): [] __irq_exit_rcu+0x240/0x440 kernel/softirq.c:659 ---[ end trace fe9d40fb68e3165b ]---