------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 77 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Modules linked in:
CPU: 0 PID: 77 Comm: kworker/u32:4 Not tainted 6.9.0-syzkaller-09868-g6e51b4b5bbc0 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: events_unbound netfs_write_collection_worker
RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Code: ff 89 de e8 08 07 11 fd 84 db 0f 85 66 ff ff ff e8 5b 0c 11 fd c6 05 9c 52 4e 0b 01 90 48 c7 c7 a0 30 8f 8b e8 07 8c d3 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 38 0c 11 fd 0f b6 1d 77 52 4e 0b 31
RSP: 0018:ffffc90000dff9b8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81510229
RDX: ffff88801a11a440 RSI: ffffffff81510236 RDI: 0000000000000001
RBP: ffff88807ebec008 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000005 R12: 0000000000000000
R13: ffff88807ebec008 R14: ffff88802bf4f400 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff88802c000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00100d000 CR3: 00000000264a6000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __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]
 p9_req_put+0x1f4/0x250 net/9p/client.c:402
 p9_client_clunk+0xc2/0x170 net/9p/client.c:1447
 p9_fid_put include/net/9p/client.h:280 [inline]
 v9fs_free_request+0xdc/0x110 fs/9p/vfs_addr.c:138
 netfs_free_request+0x22c/0x690 fs/netfs/objects.c:133
 netfs_put_request+0x19b/0x1f0 fs/netfs/objects.c:165
 netfs_write_collection_worker+0x19d0/0x59e0 fs/netfs/write_collect.c:701
 process_one_work+0x958/0x1ad0 kernel/workqueue.c:3231
 process_scheduled_works kernel/workqueue.c:3312 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>