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Subject[PATCHv2] vsock: Fix blocking ops call in prepare_to_wait
Date
We receoved a bug report from someone using vmware:

WARNING: CPU: 3 PID: 660 at kernel/sched/core.c:7389
__might_sleep+0x7d/0x90()
do not call blocking ops when !TASK_RUNNING; state=1 set at
[<ffffffff810fa68d>] prepare_to_wait+0x2d/0x90
Modules linked in: vmw_vsock_vmci_transport vsock snd_seq_midi
snd_seq_midi_event snd_ens1371 iosf_mbi gameport snd_rawmidi
snd_ac97_codec ac97_bus snd_seq coretemp snd_seq_device snd_pcm
snd_timer snd soundcore ppdev crct10dif_pclmul crc32_pclmul
ghash_clmulni_intel vmw_vmci vmw_balloon i2c_piix4 shpchp parport_pc
parport acpi_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sunrpc btrfs
xor raid6_pq 8021q garp stp llc mrp crc32c_intel serio_raw mptspi vmwgfx
drm_kms_helper ttm drm scsi_transport_spi mptscsih e1000 ata_generic
mptbase pata_acpi
CPU: 3 PID: 660 Comm: vmtoolsd Not tainted
4.2.0-0.rc1.git3.1.fc23.x86_64 #1
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop
Reference Platform, BIOS 6.00 05/20/2014
0000000000000000 0000000049e617f3 ffff88006ac37ac8 ffffffff818641f5
0000000000000000 ffff88006ac37b20 ffff88006ac37b08 ffffffff810ab446
ffff880068009f40 ffffffff81c63bc0 0000000000000061 0000000000000000
Call Trace:
[<ffffffff818641f5>] dump_stack+0x4c/0x65
[<ffffffff810ab446>] warn_slowpath_common+0x86/0xc0
[<ffffffff810ab4d5>] warn_slowpath_fmt+0x55/0x70
[<ffffffff8112551d>] ? debug_lockdep_rcu_enabled+0x1d/0x20
[<ffffffff810fa68d>] ? prepare_to_wait+0x2d/0x90
[<ffffffff810fa68d>] ? prepare_to_wait+0x2d/0x90
[<ffffffff810da2bd>] __might_sleep+0x7d/0x90
[<ffffffff812163b3>] __might_fault+0x43/0xa0
[<ffffffff81430477>] copy_from_iter+0x87/0x2a0
[<ffffffffa039460a>] __qp_memcpy_to_queue+0x9a/0x1b0 [vmw_vmci]
[<ffffffffa0394740>] ? qp_memcpy_to_queue+0x20/0x20 [vmw_vmci]
[<ffffffffa0394757>] qp_memcpy_to_queue_iov+0x17/0x20 [vmw_vmci]
[<ffffffffa0394d50>] qp_enqueue_locked+0xa0/0x140 [vmw_vmci]
[<ffffffffa039593f>] vmci_qpair_enquev+0x4f/0xd0 [vmw_vmci]
[<ffffffffa04847bb>] vmci_transport_stream_enqueue+0x1b/0x20
[vmw_vsock_vmci_transport]
[<ffffffffa047ae05>] vsock_stream_sendmsg+0x2c5/0x320 [vsock]
[<ffffffff810fabd0>] ? wake_atomic_t_function+0x70/0x70
[<ffffffff81702af8>] sock_sendmsg+0x38/0x50
[<ffffffff81702ff4>] SYSC_sendto+0x104/0x190
[<ffffffff8126e25a>] ? vfs_read+0x8a/0x140
[<ffffffff817042ee>] SyS_sendto+0xe/0x10
[<ffffffff8186d9ae>] entry_SYSCALL_64_fastpath+0x12/0x76

transport->stream_enqueue may call copy_to_user so it should
not be called inside a prepare_to_wait. Narrow the scope of
the prepare_to_wait to avoid the bad call. This also applies
to vsock_stream_recvmsg as well.

Reported-by: Vinson Lee <vlee@freedesktop.org>
Tested-by: Vinson Lee <vlee@freedesktop.org>
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
---
v2: fix same issue in recvmsg path as well.
---
net/vmw_vsock/af_vsock.c | 19 ++++++-------------
1 file changed, 6 insertions(+), 13 deletions(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 7fd1220..bbe65dc 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1557,8 +1557,6 @@ static int vsock_stream_sendmsg(struct socket *sock, struct msghdr *msg,
if (err < 0)
goto out;

- prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
-
while (total_written < len) {
ssize_t written;

@@ -1578,7 +1576,9 @@ static int vsock_stream_sendmsg(struct socket *sock, struct msghdr *msg,
goto out_wait;

release_sock(sk);
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
timeout = schedule_timeout(timeout);
+ finish_wait(sk_sleep(sk), &wait);
lock_sock(sk);
if (signal_pending(current)) {
err = sock_intr_errno(timeout);
@@ -1588,8 +1588,6 @@ static int vsock_stream_sendmsg(struct socket *sock, struct msghdr *msg,
goto out_wait;
}

- prepare_to_wait(sk_sleep(sk), &wait,
- TASK_INTERRUPTIBLE);
}

/* These checks occur both as part of and after the loop
@@ -1635,7 +1633,6 @@ static int vsock_stream_sendmsg(struct socket *sock, struct msghdr *msg,
out_wait:
if (total_written > 0)
err = total_written;
- finish_wait(sk_sleep(sk), &wait);
out:
release_sock(sk);
return err;
@@ -1716,7 +1713,6 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
if (err < 0)
goto out;

- prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);

while (1) {
s64 ready = vsock_stream_has_data(vsk);
@@ -1727,7 +1723,7 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
*/

err = -ENOMEM;
- goto out_wait;
+ goto out;
} else if (ready > 0) {
ssize_t read;

@@ -1750,7 +1746,7 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
vsk, target, read,
!(flags & MSG_PEEK), &recv_data);
if (err < 0)
- goto out_wait;
+ goto out;

if (read >= target || flags & MSG_PEEK)
break;
@@ -1773,7 +1769,9 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
break;

release_sock(sk);
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
timeout = schedule_timeout(timeout);
+ finish_wait(sk_sleep(sk), &wait);
lock_sock(sk);

if (signal_pending(current)) {
@@ -1783,9 +1781,6 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
err = -EAGAIN;
break;
}
-
- prepare_to_wait(sk_sleep(sk), &wait,
- TASK_INTERRUPTIBLE);
}
}

@@ -1816,8 +1811,6 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
err = copied;
}

-out_wait:
- finish_wait(sk_sleep(sk), &wait);
out:
release_sock(sk);
return err;
--
2.5.0
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