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Replace xenbus workaround with upstreamed fix

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pull/19/head
Simon Gaiser 6 years ago
parent 67e33e0360
commit e4913200f6
9 changed files with 143 additions and 1701 deletions
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49
patches.xen/2a22ee6c3ab1-xen-xenbus_dev_frontend-Fix-XS_TRANSACTION_END-handl.patch
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From 2a22ee6c3ab1d761bc9c04f1e4117edd55b82f09 Mon Sep 17 00:00:00 2001
From: Simon Gaiser <simon@invisiblethingslab.com>
Date: Thu, 15 Mar 2018 03:43:20 +0100
Subject: [PATCH 1/3] xen: xenbus_dev_frontend: Fix XS_TRANSACTION_END handling
Commit fd8aa9095a95 ("xen: optimize xenbus driver for multiple
concurrent xenstore accesses") made a subtle change to the semantic of
xenbus_dev_request_and_reply() and xenbus_transaction_end().
Before on an error response to XS_TRANSACTION_END
xenbus_dev_request_and_reply() would not decrement the active
transaction counter. But xenbus_transaction_end() has always counted the
transaction as finished regardless of the response.
The new behavior is that xenbus_dev_request_and_reply() and
xenbus_transaction_end() will always count the transaction as finished
regardless the response code (handled in xs_request_exit()).
But xenbus_dev_frontend tries to end a transaction on closing of the
device if the XS_TRANSACTION_END failed before. Trying to close the
transaction twice corrupts the reference count. So fix this by also
considering a transaction closed if we have sent XS_TRANSACTION_END once
regardless of the return code.
Cc: <stable@vger.kernel.org> # 4.11
Fixes: fd8aa9095a95 ("xen: optimize xenbus driver for multiple concurrent xenstore accesses")
Signed-off-by: Simon Gaiser <simon@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
drivers/xen/xenbus/xenbus_dev_frontend.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index a493e99bed21..81a84b3c1c50 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -365,7 +365,7 @@ void xenbus_dev_queue_reply(struct xb_req_data *req)
if (WARN_ON(rc))
goto out;
}
- } else if (req->msg.type == XS_TRANSACTION_END) {
+ } else if (req->type == XS_TRANSACTION_END) {
trans = xenbus_get_transaction(u, req->msg.tx_id);
if (WARN_ON(!trans))
goto out;
--
2.16.2

55
patches.xen/8fe5ab411209-xen-xenbus_dev_frontend-Verify-body-of-XS_TRANSACTIO.patch
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From 8fe5ab411209ac6e2c7021131e622fd004506d1a Mon Sep 17 00:00:00 2001
From: Simon Gaiser <simon@invisiblethingslab.com>
Date: Thu, 15 Mar 2018 03:43:22 +0100
Subject: [PATCH 3/3] xen: xenbus_dev_frontend: Verify body of
XS_TRANSACTION_END
By guaranteeing that the argument of XS_TRANSACTION_END is valid we can
assume that the transaction has been closed when we get an XS_ERROR
response from xenstore (Note that we already verify that it's a valid
transaction id).
Signed-off-by: Simon Gaiser <simon@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
drivers/xen/xenbus/xenbus_dev_frontend.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index 81a84b3c1c50..0d6d9264d6a9 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -429,6 +429,10 @@ static int xenbus_write_transaction(unsigned msg_type,
{
int rc;
struct xenbus_transaction_holder *trans = NULL;
+ struct {
+ struct xsd_sockmsg hdr;
+ char body[];
+ } *msg = (void *)u->u.buffer;
if (msg_type == XS_TRANSACTION_START) {
trans = kzalloc(sizeof(*trans), GFP_KERNEL);
@@ -437,11 +441,15 @@ static int xenbus_write_transaction(unsigned msg_type,
goto out;
}
list_add(&trans->list, &u->transactions);
- } else if (u->u.msg.tx_id != 0 &&
- !xenbus_get_transaction(u, u->u.msg.tx_id))
+ } else if (msg->hdr.tx_id != 0 &&
+ !xenbus_get_transaction(u, msg->hdr.tx_id))
return xenbus_command_reply(u, XS_ERROR, "ENOENT");
+ else if (msg_type == XS_TRANSACTION_END &&
+ !(msg->hdr.len == 2 &&
+ (!strcmp(msg->body, "T") || !strcmp(msg->body, "F"))))
+ return xenbus_command_reply(u, XS_ERROR, "EINVAL");
- rc = xenbus_dev_request_and_reply(&u->u.msg, u);
+ rc = xenbus_dev_request_and_reply(&msg->hdr, u);
if (rc && trans) {
list_del(&trans->list);
kfree(trans);
--
2.16.2

52
patches.xen/Revert-xen-avoid-deadlock-in-xenbus-driver.patch
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@ -1,52 +0,0 @@
From 7eed8836d3046a93848b891399ebbeee1d56e4f5 Mon Sep 17 00:00:00 2001
From: Simon Gaiser <simon@invisiblethingslab.com>
Date: Tue, 30 Jan 2018 07:34:49 +0100
Subject: [PATCH 2/4] Revert "xen: avoid deadlock in xenbus driver"
This reverts commit 1a3fc2c402810bf336882e695abd1678dbc8d279.
---
drivers/xen/xenbus/xenbus_comms.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c
index 5b081a01779d..856ada5d39c9 100644
--- a/drivers/xen/xenbus/xenbus_comms.c
+++ b/drivers/xen/xenbus/xenbus_comms.c
@@ -299,7 +299,17 @@ static int process_msg(void)
mutex_lock(&xb_write_mutex);
list_for_each_entry(req, &xs_reply_list, list) {
if (req->msg.req_id == state.msg.req_id) {
- list_del(&req->list);
+ if (req->state == xb_req_state_wait_reply) {
+ req->msg.type = state.msg.type;
+ req->msg.len = state.msg.len;
+ req->body = state.body;
+ req->state = xb_req_state_got_reply;
+ list_del(&req->list);
+ req->cb(req);
+ } else {
+ list_del(&req->list);
+ kfree(req);
+ }
err = 0;
break;
}
@@ -307,15 +317,6 @@ static int process_msg(void)
mutex_unlock(&xb_write_mutex);
if (err)
goto out;
-
- if (req->state == xb_req_state_wait_reply) {
- req->msg.type = state.msg.type;
- req->msg.len = state.msg.len;
- req->body = state.body;
- req->state = xb_req_state_got_reply;
- req->cb(req);
- } else
- kfree(req);
}
mutex_unlock(&xs_response_mutex);
--
2.15.1

34
patches.xen/Revert-xen-avoid-deadlock-in-xenbus.patch
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From f9d9d4c0a6bf6d693d882ea99f0e57b0241b3370 Mon Sep 17 00:00:00 2001
From: Simon Gaiser <simon@invisiblethingslab.com>
Date: Tue, 30 Jan 2018 07:34:40 +0100
Subject: [PATCH 1/4] Revert "xen: avoid deadlock in xenbus"
This reverts commit 529871bb3c0675d0b425e2070d5a739db097be98.
---
drivers/xen/xenbus/xenbus_xs.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 3e59590c7254..e46080214955 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -857,8 +857,6 @@ static int xenwatch_thread(void *unused)
struct list_head *ent;
struct xs_watch_event *event;
- xenwatch_pid = current->pid;
-
for (;;) {
wait_event_interruptible(watch_events_waitq,
!list_empty(&watch_events));
@@ -927,6 +925,7 @@ int xs_init(void)
task = kthread_run(xenwatch_thread, NULL, "xenwatch");
if (IS_ERR(task))
return PTR_ERR(task);
+ xenwatch_pid = task->pid;
/* shutdown watches for kexec boot */
xs_reset_watches();
--
2.15.1

1518
patches.xen/Revert-xen-optimize-xenbus-driver-for-multiple-concu.patch
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30
patches.xen/Revert-xenbus-remove-transaction-holder-from-list-be.patch
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From 9622a541f049137fef086e45cc6ddf4dd56bb99e Mon Sep 17 00:00:00 2001
From: Simon Gaiser <simon@invisiblethingslab.com>
Date: Tue, 30 Jan 2018 07:38:17 +0100
Subject: [PATCH 3/4] Revert "xenbus: remove transaction holder from list
before freeing"
This reverts commit ac4cde398a96c1d28b1c28a0f69b6efd892a1c8a.
---
drivers/xen/xenbus/xenbus_dev_frontend.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index f3b089b7c0b6..1f4733b80c87 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -442,10 +442,8 @@ static int xenbus_write_transaction(unsigned msg_type,
return xenbus_command_reply(u, XS_ERROR, "ENOENT");
rc = xenbus_dev_request_and_reply(&u->u.msg, u);
- if (rc && trans) {
- list_del(&trans->list);
+ if (rc)
kfree(trans);
- }
out:
return rc;
--
2.15.1

60
patches.xen/Revert-xenbus-track-caller-request-id.patch
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@ -1,60 +0,0 @@
From 137e4287ebd6ccdc0982c622825c90bba940f7cf Mon Sep 17 00:00:00 2001
From: Simon Gaiser <simon@invisiblethingslab.com>
Date: Tue, 27 Feb 2018 18:14:15 +0100
Subject: [PATCH] Revert "xenbus: track caller request id"
This reverts commit 54de83d07a18bfa30bd90294bebced839bb7132f.
---
drivers/xen/xenbus/xenbus.h | 1 -
drivers/xen/xenbus/xenbus_comms.c | 1 -
drivers/xen/xenbus/xenbus_xs.c | 3 ---
3 files changed, 5 deletions(-)
diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h
index 092981171df1..149c5e7efc89 100644
--- a/drivers/xen/xenbus/xenbus.h
+++ b/drivers/xen/xenbus/xenbus.h
@@ -76,7 +76,6 @@ struct xb_req_data {
struct list_head list;
wait_queue_head_t wq;
struct xsd_sockmsg msg;
- uint32_t caller_req_id;
enum xsd_sockmsg_type type;
char *body;
const struct kvec *vec;
diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c
index d239fc3c5e3d..5b081a01779d 100644
--- a/drivers/xen/xenbus/xenbus_comms.c
+++ b/drivers/xen/xenbus/xenbus_comms.c
@@ -309,7 +309,6 @@ static int process_msg(void)
goto out;
if (req->state == xb_req_state_wait_reply) {
- req->msg.req_id = req->caller_req_id;
req->msg.type = state.msg.type;
req->msg.len = state.msg.len;
req->body = state.body;
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 3f3b29398ab8..3e59590c7254 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -227,8 +227,6 @@ static void xs_send(struct xb_req_data *req, struct xsd_sockmsg *msg)
req->state = xb_req_state_queued;
init_waitqueue_head(&req->wq);
- /* Save the caller req_id and restore it later in the reply */
- req->caller_req_id = req->msg.req_id;
req->msg.req_id = xs_request_enter(req);
mutex_lock(&xb_write_mutex);
@@ -312,7 +310,6 @@ static void *xs_talkv(struct xenbus_transaction t,
req->num_vecs = num_vecs;
req->cb = xs_wake_up;
- msg.req_id = 0;
msg.tx_id = t.id;
msg.type = type;
msg.len = 0;
--
2.16.1

35
patches.xen/b93008d1ac65-xen-xenbus-Catch-closing-of-non-existent-transaction.patch
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From b93008d1ac657dc67819330c5995e65e7c3e7978 Mon Sep 17 00:00:00 2001
From: Simon Gaiser <simon@invisiblethingslab.com>
Date: Thu, 15 Mar 2018 03:43:21 +0100
Subject: [PATCH 2/3] xen: xenbus: Catch closing of non existent transactions
Users of the xenbus functions should never close a non existent
transaction (for example by trying to closing the same transaction
twice) but better catch it in xs_request_exit() than to corrupt the
reference counter.
Signed-off-by: Simon Gaiser <simon@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
drivers/xen/xenbus/xenbus_xs.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 3f3b29398ab8..49a3874ae6bb 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -140,7 +140,9 @@ void xs_request_exit(struct xb_req_data *req)
spin_lock(&xs_state_lock);
xs_state_users--;
if ((req->type == XS_TRANSACTION_START && req->msg.type == XS_ERROR) ||
- req->type == XS_TRANSACTION_END)
+ (req->type == XS_TRANSACTION_END &&
+ !WARN_ON_ONCE(req->msg.type == XS_ERROR &&
+ !strcmp(req->body, "ENOENT"))))
xs_state_users--;
spin_unlock(&xs_state_lock);
--
2.16.2

11
series.conf
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@ -25,12 +25,9 @@ patches.xen/pci_op-cleanup.patch
# Fix for MSI support with stubdoms
patches.xen/xen-pciback-add-attribute-to-allow-MSI-enable-flag-w.patch
# Workaround HVM suspend issue with >= 4.11 by reverting the change (and
# followups) till fix lands upstream.
patches.xen/Revert-xenbus-track-caller-request-id.patch
patches.xen/Revert-xen-avoid-deadlock-in-xenbus.patch
patches.xen/Revert-xen-avoid-deadlock-in-xenbus-driver.patch
patches.xen/Revert-xenbus-remove-transaction-holder-from-list-be.patch
patches.xen/Revert-xen-optimize-xenbus-driver-for-multiple-concu.patch
# Upstreamed fix for HVM suspend issue with >= 4.11
patches.xen/2a22ee6c3ab1-xen-xenbus_dev_frontend-Fix-XS_TRANSACTION_END-handl.patch
patches.xen/b93008d1ac65-xen-xenbus-Catch-closing-of-non-existent-transaction.patch
patches.xen/8fe5ab411209-xen-xenbus_dev_frontend-Verify-body-of-XS_TRANSACTIO.patch
# Hardware-specific fixes, backported from newer kernel and/or developers branches

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