From b79470b64fa9266948d1ce8d825ced94c4f63293 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Fri, 21 Dec 2018 15:06:29 -0800 Subject: pvcalls-front: read all data before closing the connection When a connection is closing in_error is set to ENOTCONN. There could still be outstanding data on the ring left by the backend. Before closing the connection on the frontend side, drain the ring. Signed-off-by: Stefano Stabellini Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky --- drivers/xen/pvcalls-front.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index 77224d8f3e6f..e5d95aab2cb8 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -560,15 +560,13 @@ static int __read_ring(struct pvcalls_data_intf *intf, error = intf->in_error; /* get pointers before reading from the ring */ virt_rmb(); - if (error < 0) - return error; size = pvcalls_queued(prod, cons, array_size); masked_prod = pvcalls_mask(prod, array_size); masked_cons = pvcalls_mask(cons, array_size); if (size == 0) - return 0; + return error ?: size; if (len > size) len = size; -- cgit v1.2.3 From 96283f9a084e23d7cda2d3c5d1ffa6df6cf1ecec Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Fri, 21 Dec 2018 15:06:30 -0800 Subject: pvcalls-front: don't try to free unallocated rings inflight_req_id is 0 when initialized. If inflight_req_id is 0, there is no accept_map to free. Fix the check in pvcalls_front_release. Signed-off-by: Stefano Stabellini Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky --- drivers/xen/pvcalls-front.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index e5d95aab2cb8..4f3d664b3f39 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -1030,8 +1030,8 @@ int pvcalls_front_release(struct socket *sock) spin_lock(&bedata->socket_lock); list_del(&map->list); spin_unlock(&bedata->socket_lock); - if (READ_ONCE(map->passive.inflight_req_id) != - PVCALLS_INVALID_ID) { + if (READ_ONCE(map->passive.inflight_req_id) != PVCALLS_INVALID_ID && + READ_ONCE(map->passive.inflight_req_id) != 0) { pvcalls_front_free_map(bedata, map->passive.accept_map); } -- cgit v1.2.3 From beee1fbe8f7d57d6ebaa5188f9f4db89c2077196 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Fri, 21 Dec 2018 15:06:31 -0800 Subject: pvcalls-front: properly allocate sk Don't use kzalloc: it ends up leaving sk->sk_prot not properly initialized. Use sk_alloc instead and define our own trivial struct proto. Signed-off-by: Stefano Stabellini Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky --- drivers/xen/pvcalls-front.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'drivers/xen') diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index 4f3d664b3f39..01588582ae66 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -31,6 +31,12 @@ #define PVCALLS_NR_RSP_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE) #define PVCALLS_FRONT_MAX_SPIN 5000 +static struct proto pvcalls_proto = { + .name = "PVCalls", + .owner = THIS_MODULE, + .obj_size = sizeof(struct sock), +}; + struct pvcalls_bedata { struct xen_pvcalls_front_ring ring; grant_ref_t ref; @@ -837,7 +843,7 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) received: map2->sock = newsock; - newsock->sk = kzalloc(sizeof(*newsock->sk), GFP_KERNEL); + newsock->sk = sk_alloc(sock_net(sock->sk), PF_INET, GFP_KERNEL, &pvcalls_proto, false); if (!newsock->sk) { bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID; map->passive.inflight_req_id = PVCALLS_INVALID_ID; -- cgit v1.2.3 From d90a1ca60a1eccb4383fe203c76223ab4c0799ed Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Fri, 21 Dec 2018 15:06:32 -0800 Subject: pvcalls-front: don't return error when the ring is full When the ring is full, size == array_size. It is not an error condition, so simply return 0 instead of an error. Signed-off-by: Stefano Stabellini Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky --- drivers/xen/pvcalls-front.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/xen') diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index 01588582ae66..1a893a164349 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -475,8 +475,10 @@ static int __write_ring(struct pvcalls_data_intf *intf, virt_mb(); size = pvcalls_queued(prod, cons, array_size); - if (size >= array_size) + if (size > array_size) return -EINVAL; + if (size == array_size) + return 0; if (len > array_size - size) len = array_size - size; -- cgit v1.2.3 From e6587cdbd732eacb4c7ce592ed46f7bbcefb655f Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Fri, 21 Dec 2018 15:06:33 -0800 Subject: pvcalls-back: set -ENOTCONN in pvcalls_conn_back_read When a connection is closing we receive on pvcalls_sk_state_change notification. Instead of setting the connection as closed immediately (-ENOTCONN), let's read one more time from it: pvcalls_conn_back_read will set the connection as closed when necessary. That way, we avoid races between pvcalls_sk_state_change and pvcalls_back_ioworker. Signed-off-by: Stefano Stabellini Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky --- drivers/xen/pvcalls-back.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c index 2e5d845b5091..71b628774c6f 100644 --- a/drivers/xen/pvcalls-back.c +++ b/drivers/xen/pvcalls-back.c @@ -160,9 +160,10 @@ static void pvcalls_conn_back_read(void *opaque) /* write the data, then modify the indexes */ virt_wmb(); - if (ret < 0) + if (ret < 0) { + atomic_set(&map->read, 0); intf->in_error = ret; - else + } else intf->in_prod = prod + ret; /* update the indexes, then notify the other end */ virt_wmb(); @@ -288,7 +289,7 @@ static void pvcalls_sk_state_change(struct sock *sock) return; intf = map->ring; - intf->in_error = -ENOTCONN; + atomic_inc(&map->read); notify_remote_via_irq(map->irq); } -- cgit v1.2.3 From 1f8ce09b36c41a026a37a24b20efa32000892a64 Mon Sep 17 00:00:00 2001 From: YueHaibing Date: Fri, 4 Jan 2019 06:03:40 +0000 Subject: xen/pvcalls: remove set but not used variable 'intf' Fixes gcc '-Wunused-but-set-variable' warning: drivers/xen/pvcalls-back.c: In function 'pvcalls_sk_state_change': drivers/xen/pvcalls-back.c:286:28: warning: variable 'intf' set but not used [-Wunused-but-set-variable] It not used since e6587cdbd732 ("pvcalls-back: set -ENOTCONN in pvcalls_conn_back_read") Signed-off-by: YueHaibing Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky --- drivers/xen/pvcalls-back.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c index 71b628774c6f..7aa64d1b119c 100644 --- a/drivers/xen/pvcalls-back.c +++ b/drivers/xen/pvcalls-back.c @@ -283,12 +283,10 @@ static int pvcalls_back_socket(struct xenbus_device *dev, static void pvcalls_sk_state_change(struct sock *sock) { struct sock_mapping *map = sock->sk_user_data; - struct pvcalls_data_intf *intf; if (map == NULL) return; - intf = map->ring; atomic_inc(&map->read); notify_remote_via_irq(map->irq); } -- cgit v1.2.3 From 9f51c05dc41a6d69423e3d03d18eb7ab22f9ec19 Mon Sep 17 00:00:00 2001 From: Wen Yang Date: Wed, 5 Dec 2018 10:35:50 +0800 Subject: pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross Suggested-by: Boris Ostrovsky Suggested-by: Stefano Stabellini Signed-off-by: Wen Yang Acked-by: Stefano Stabellini CC: Julia Lawall CC: Boris Ostrovsky CC: Juergen Gross CC: Stefano Stabellini CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky --- drivers/xen/pvcalls-front.c | 81 +++++++++++++++++++++++++++++++++------------ 1 file changed, 59 insertions(+), 22 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index 1a893a164349..307861f9e485 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -341,6 +341,39 @@ int pvcalls_front_socket(struct socket *sock) return ret; } +static void free_active_ring(struct sock_mapping *map) +{ + free_pages((unsigned long)map->active.data.in, + map->active.ring->ring_order); + free_page((unsigned long)map->active.ring); +} + +static int alloc_active_ring(struct sock_mapping *map) +{ + void *bytes; + + map->active.ring = (struct pvcalls_data_intf *) + get_zeroed_page(GFP_KERNEL); + if (!map->active.ring) + goto out; + + map->active.ring->ring_order = PVCALLS_RING_ORDER; + bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, + PVCALLS_RING_ORDER); + if (!bytes) + goto out; + + map->active.data.in = bytes; + map->active.data.out = bytes + + XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); + + return 0; + +out: + free_active_ring(map); + return -ENOMEM; +} + static int create_active(struct sock_mapping *map, int *evtchn) { void *bytes; @@ -349,15 +382,7 @@ static int create_active(struct sock_mapping *map, int *evtchn) *evtchn = -1; init_waitqueue_head(&map->active.inflight_conn_req); - map->active.ring = (struct pvcalls_data_intf *) - __get_free_page(GFP_KERNEL | __GFP_ZERO); - if (map->active.ring == NULL) - goto out_error; - map->active.ring->ring_order = PVCALLS_RING_ORDER; - bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, - PVCALLS_RING_ORDER); - if (bytes == NULL) - goto out_error; + bytes = map->active.data.in; for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++) map->active.ring->ref[i] = gnttab_grant_foreign_access( pvcalls_front_dev->otherend_id, @@ -367,10 +392,6 @@ static int create_active(struct sock_mapping *map, int *evtchn) pvcalls_front_dev->otherend_id, pfn_to_gfn(virt_to_pfn((void *)map->active.ring)), 0); - map->active.data.in = bytes; - map->active.data.out = bytes + - XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); - ret = xenbus_alloc_evtchn(pvcalls_front_dev, evtchn); if (ret) goto out_error; @@ -391,8 +412,6 @@ static int create_active(struct sock_mapping *map, int *evtchn) out_error: if (*evtchn >= 0) xenbus_free_evtchn(pvcalls_front_dev, *evtchn); - free_pages((unsigned long)map->active.data.in, PVCALLS_RING_ORDER); - free_page((unsigned long)map->active.ring); return ret; } @@ -412,17 +431,24 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, return PTR_ERR(map); bedata = dev_get_drvdata(&pvcalls_front_dev->dev); + ret = alloc_active_ring(map); + if (ret < 0) { + pvcalls_exit_sock(sock); + return ret; + } spin_lock(&bedata->socket_lock); ret = get_request(bedata, &req_id); if (ret < 0) { spin_unlock(&bedata->socket_lock); + free_active_ring(map); pvcalls_exit_sock(sock); return ret; } ret = create_active(map, &evtchn); if (ret < 0) { spin_unlock(&bedata->socket_lock); + free_active_ring(map); pvcalls_exit_sock(sock); return ret; } @@ -786,25 +812,36 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) } } - spin_lock(&bedata->socket_lock); - ret = get_request(bedata, &req_id); - if (ret < 0) { + map2 = kzalloc(sizeof(*map2), GFP_KERNEL); + if (map2 == NULL) { clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags); - spin_unlock(&bedata->socket_lock); + pvcalls_exit_sock(sock); + return -ENOMEM; + } + ret = alloc_active_ring(map2); + if (ret < 0) { + clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, + (void *)&map->passive.flags); + kfree(map2); pvcalls_exit_sock(sock); return ret; } - map2 = kzalloc(sizeof(*map2), GFP_ATOMIC); - if (map2 == NULL) { + spin_lock(&bedata->socket_lock); + ret = get_request(bedata, &req_id); + if (ret < 0) { clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags); spin_unlock(&bedata->socket_lock); + free_active_ring(map2); + kfree(map2); pvcalls_exit_sock(sock); - return -ENOMEM; + return ret; } + ret = create_active(map2, &evtchn); if (ret < 0) { + free_active_ring(map2); kfree(map2); clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags); -- cgit v1.2.3 From b4711098066f1cf808d4dc11a1a842860a3292fe Mon Sep 17 00:00:00 2001 From: Wen Yang Date: Tue, 15 Jan 2019 10:31:27 +0800 Subject: pvcalls-front: fix potential null dereference static checker warning: drivers/xen/pvcalls-front.c:373 alloc_active_ring() error: we previously assumed 'map->active.ring' could be null (see line 357) drivers/xen/pvcalls-front.c 351 static int alloc_active_ring(struct sock_mapping *map) 352 { 353 void *bytes; 354 355 map->active.ring = (struct pvcalls_data_intf *) 356 get_zeroed_page(GFP_KERNEL); 357 if (!map->active.ring) ^^^^^^^^^^^^^^^^^ Check 358 goto out; 359 360 map->active.ring->ring_order = PVCALLS_RING_ORDER; 361 bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 362 PVCALLS_RING_ORDER); 363 if (!bytes) 364 goto out; 365 366 map->active.data.in = bytes; 367 map->active.data.out = bytes + 368 XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); 369 370 return 0; 371 372 out: --> 373 free_active_ring(map); ^^^ Add null check on map->active.ring before dereferencing it to avoid any NULL pointer dereferences. Fixes: 9f51c05dc41a ("pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock") Reported-by: Dan Carpenter Suggested-by: Boris Ostrovsky Signed-off-by: Wen Yang Reviewed-by: Boris Ostrovsky CC: Boris Ostrovsky CC: Juergen Gross CC: Stefano Stabellini CC: Dan Carpenter CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky --- drivers/xen/pvcalls-front.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/xen') diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index 307861f9e485..8a249c95c193 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -343,6 +343,9 @@ int pvcalls_front_socket(struct socket *sock) static void free_active_ring(struct sock_mapping *map) { + if (!map->active.ring) + return; + free_pages((unsigned long)map->active.data.in, map->active.ring->ring_order); free_page((unsigned long)map->active.ring); -- cgit v1.2.3 From 867cefb4cb1012f42cada1c7d1f35ac8dd276071 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 14 Jan 2019 13:44:13 +0100 Subject: xen: Fix x86 sched_clock() interface for xen Commit f94c8d11699759 ("sched/clock, x86/tsc: Rework the x86 'unstable' sched_clock() interface") broke Xen guest time handling across migration: [ 187.249951] Freezing user space processes ... (elapsed 0.001 seconds) done. [ 187.251137] OOM killer disabled. [ 187.251137] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done. [ 187.252299] suspending xenstore... [ 187.266987] xen:grant_table: Grant tables using version 1 layout [18446743811.706476] OOM killer enabled. [18446743811.706478] Restarting tasks ... done. [18446743811.720505] Setting capacity to 16777216 Fix that by setting xen_sched_clock_offset at resume time to ensure a monotonic clock value. [boris: replaced pr_info() with pr_info_once() in xen_callback_vector() to avoid printing with incorrect timestamp during resume (as we haven't re-adjusted the clock yet)] Fixes: f94c8d11699759 ("sched/clock, x86/tsc: Rework the x86 'unstable' sched_clock() interface") Cc: # 4.11 Reported-by: Hans van Kranenburg Signed-off-by: Juergen Gross Tested-by: Hans van Kranenburg Signed-off-by: Boris Ostrovsky --- arch/x86/xen/time.c | 12 +++++++++--- drivers/xen/events/events_base.c | 2 +- 2 files changed, 10 insertions(+), 4 deletions(-) (limited to 'drivers/xen') diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c index 72bf446c3fee..6e29794573b7 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -361,8 +361,6 @@ void xen_timer_resume(void) { int cpu; - pvclock_resume(); - if (xen_clockevent != &xen_vcpuop_clockevent) return; @@ -379,12 +377,15 @@ static const struct pv_time_ops xen_time_ops __initconst = { }; static struct pvclock_vsyscall_time_info *xen_clock __read_mostly; +static u64 xen_clock_value_saved; void xen_save_time_memory_area(void) { struct vcpu_register_time_memory_area t; int ret; + xen_clock_value_saved = xen_clocksource_read() - xen_sched_clock_offset; + if (!xen_clock) return; @@ -404,7 +405,7 @@ void xen_restore_time_memory_area(void) int ret; if (!xen_clock) - return; + goto out; t.addr.v = &xen_clock->pvti; @@ -421,6 +422,11 @@ void xen_restore_time_memory_area(void) if (ret != 0) pr_notice("Cannot restore secondary vcpu_time_info (err %d)", ret); + +out: + /* Need pvclock_resume() before using xen_clocksource_read(). */ + pvclock_resume(); + xen_sched_clock_offset = xen_clocksource_read() - xen_clock_value_saved; } static void xen_setup_vsyscall_time_info(void) diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 93194f3e7540..117e76b2f939 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -1650,7 +1650,7 @@ void xen_callback_vector(void) xen_have_vector_callback = 0; return; } - pr_info("Xen HVM callback vector for event delivery is enabled\n"); + pr_info_once("Xen HVM callback vector for event delivery is enabled\n"); alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, xen_hvm_callback_vector); } -- cgit v1.2.3