INFO: task can't die in p9_client_rpc (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    0eedceaf Add linux-next specific files for 20201201
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11111df7500000
kernel config:  https://syzkaller.appspot.com/x/.config?x=55aec7153b7827ea
dashboard link: https://syzkaller.appspot.com/bug?extid=4ff9239a00671c7c656f
compiler:       gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4ff9239a00671c7c656f@xxxxxxxxxxxxxxxxxxxxxxxxx

INFO: task syz-executor.2:10555 can't die for more than 143 seconds.
task:syz-executor.2  state:D stack:27024 pid:10555 ppid:  8514 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:4325 [inline]
 __schedule+0x8cd/0x2150 kernel/sched/core.c:5076
 schedule+0xcf/0x270 kernel/sched/core.c:5155
 p9_client_rpc+0x400/0x1240 net/9p/client.c:759
 p9_client_flush+0x1f9/0x430 net/9p/client.c:667
 p9_client_rpc+0xfde/0x1240 net/9p/client.c:784
 p9_client_version net/9p/client.c:955 [inline]
 p9_client_create+0xae1/0x1110 net/9p/client.c:1055
 v9fs_session_init+0x1dd/0x1770 fs/9p/v9fs.c:406
 v9fs_mount+0x79/0x9b0 fs/9p/vfs_super.c:126
 legacy_get_tree+0x105/0x220 fs/fs_context.c:592
 vfs_get_tree+0x89/0x2f0 fs/super.c:1549
 do_new_mount fs/namespace.c:2896 [inline]
 path_mount+0x12ae/0x1e70 fs/namespace.c:3227
 do_mount fs/namespace.c:3240 [inline]
 __do_sys_mount fs/namespace.c:3448 [inline]
 __se_sys_mount fs/namespace.c:3425 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3425
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45de79
RSP: 002b:00007f4ba88a6c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045de79
RDX: 0000000020000200 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 000000000118bf70 R08: 0000000020000140 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007fff44b1496f R14: 00007f4ba88a79c0 R15: 000000000118bf2c

Showing all locks held in the system:
2 locks held by kworker/u4:3/81:
1 lock held by khungtaskd/1618:
 #0: ffffffff8b33a7a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6254
1 lock held by systemd-journal/4903:
1 lock held by in:imklog/8195:
 #0: ffff88801dba7270 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:923

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