From: Dexuan Cui <decui@microsoft.com>
To: gregkh@linuxfoundation.org, davem@davemloft.net,
stephen@networkplumber.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
driverdev-devel@linuxdriverproject.org, olaf@aepfle.de,
apw@canonical.com, jasowang@redhat.com, kys@microsoft.com
Cc: pebolle@tiscali.nl, stefanha@redhat.com, vkuznets@redhat.com,
dan.carpenter@oracle.com
Subject: [PATCH V4 7/7] Drivers: hv: vmbus: disable local interrupt when hvsock's callback is running
Date: Tue, 28 Jul 2015 05:35:30 -0700 [thread overview]
Message-ID: <1438086930-19483-1-git-send-email-decui@microsoft.com> (raw)
In the SMP guest case, when the per-channel callback hvsock_events() is
running on virtual CPU A, if the guest tries to close the connection on
virtual CPU B: we invoke vmbus_close() -> vmbus_close_internal(),
then we can have trouble: on B, vmbus_close_internal() will send IPI
reset_channel_cb() to A, trying to set channel->onchannel_callbackto NULL;
on A, if the IPI handler happens between
"if (channel->onchannel_callback != NULL)" and invoking
channel->onchannel_callback, we'll invoke a function pointer of NULL.
This is why the patch is necessary.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
drivers/hv/connection.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 4fc2e88..4766fd8 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -319,6 +319,9 @@ static void process_chn_event(u32 relid)
void *arg;
bool read_state;
u32 bytes_to_read;
+ bool is_hvsock = false;
+
+ local_irq_disable();
/*
* Find the channel based on this relid and invokes the
@@ -327,7 +330,11 @@ static void process_chn_event(u32 relid)
channel = pcpu_relid2channel(relid);
if (!channel)
- return;
+ goto out;
+
+ is_hvsock = is_hvsock_channel(channel);
+ if (!is_hvsock)
+ local_irq_enable();
/*
* A channel once created is persistent even when there
@@ -363,6 +370,12 @@ static void process_chn_event(u32 relid)
bytes_to_read = 0;
} while (read_state && (bytes_to_read != 0));
}
+
+ /* local_irq_enable() is alredy invoked above */
+ if (!is_hvsock)
+ return;
+out:
+ local_irq_enable();
}
/*
--
2.1.0
next reply other threads:[~2015-07-28 11:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-28 12:35 Dexuan Cui [this message]
2015-07-29 22:28 ` [PATCH V4 7/7] Drivers: hv: vmbus: disable local interrupt when hvsock's callback is running David Miller
2015-07-30 10:18 ` Dexuan Cui
2015-08-06 4:44 ` Dexuan Cui
2015-08-06 17:50 ` KY Srinivasan
2015-08-07 10:24 ` Dexuan Cui
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