drivers/xen/pvcalls-front.c | 46 +++++++++++++++++++++---------------- 1 file changed, 26 insertions(+), 20 deletions(-)
bind_evtchn_to_irqhandler() shouldn't be called under spinlock, as it
can sleep.
This requires to move the calls of create_active() out of the locked
regions. This is no problem, as the worst which could happen would be
a spurious call of the interrupt handler, causing a spurious wake_up().
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/lkml/Y+JUIl64UDmdkboh@kadam/
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- remove stale spin_unlock() (Oleksandr Tyshchenko)
---
drivers/xen/pvcalls-front.c | 46 +++++++++++++++++++++----------------
1 file changed, 26 insertions(+), 20 deletions(-)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index d5d589bda243..b72ee9379d77 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -227,22 +227,30 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
static void free_active_ring(struct sock_mapping *map);
-static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
- struct sock_mapping *map)
+static void pvcalls_front_destroy_active(struct pvcalls_bedata *bedata,
+ struct sock_mapping *map)
{
int i;
unbind_from_irqhandler(map->active.irq, map);
- spin_lock(&bedata->socket_lock);
- if (!list_empty(&map->list))
- list_del_init(&map->list);
- spin_unlock(&bedata->socket_lock);
+ if (bedata) {
+ spin_lock(&bedata->socket_lock);
+ if (!list_empty(&map->list))
+ list_del_init(&map->list);
+ spin_unlock(&bedata->socket_lock);
+ }
for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
gnttab_end_foreign_access(map->active.ring->ref[i], NULL);
gnttab_end_foreign_access(map->active.ref, NULL);
free_active_ring(map);
+}
+
+static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
+ struct sock_mapping *map)
+{
+ pvcalls_front_destroy_active(bedata, map);
kfree(map);
}
@@ -433,19 +441,18 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
pvcalls_exit_sock(sock);
return ret;
}
-
- spin_lock(&bedata->socket_lock);
- ret = get_request(bedata, &req_id);
+ ret = create_active(map, &evtchn);
if (ret < 0) {
- spin_unlock(&bedata->socket_lock);
free_active_ring(map);
pvcalls_exit_sock(sock);
return ret;
}
- ret = create_active(map, &evtchn);
+
+ spin_lock(&bedata->socket_lock);
+ ret = get_request(bedata, &req_id);
if (ret < 0) {
spin_unlock(&bedata->socket_lock);
- free_active_ring(map);
+ pvcalls_front_destroy_active(NULL, map);
pvcalls_exit_sock(sock);
return ret;
}
@@ -821,28 +828,27 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
pvcalls_exit_sock(sock);
return ret;
}
- spin_lock(&bedata->socket_lock);
- ret = get_request(bedata, &req_id);
+ ret = create_active(map2, &evtchn);
if (ret < 0) {
- clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
- (void *)&map->passive.flags);
- spin_unlock(&bedata->socket_lock);
free_active_ring(map2);
kfree(map2);
+ clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+ (void *)&map->passive.flags);
pvcalls_exit_sock(sock);
return ret;
}
- ret = create_active(map2, &evtchn);
+ spin_lock(&bedata->socket_lock);
+ ret = get_request(bedata, &req_id);
if (ret < 0) {
- free_active_ring(map2);
- kfree(map2);
clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
(void *)&map->passive.flags);
spin_unlock(&bedata->socket_lock);
+ pvcalls_front_free_map(bedata, map2);
pvcalls_exit_sock(sock);
return ret;
}
+
list_add_tail(&map2->list, &bedata->socket_mappings);
req = RING_GET_REQUEST(&bedata->ring, req_id);
--
2.35.3
On Mon, 3 Apr 2023, Juergen Gross wrote: > bind_evtchn_to_irqhandler() shouldn't be called under spinlock, as it > can sleep. > > This requires to move the calls of create_active() out of the locked > regions. This is no problem, as the worst which could happen would be > a spurious call of the interrupt handler, causing a spurious wake_up(). > > Reported-by: Dan Carpenter <error27@gmail.com> > Link: https://lore.kernel.org/lkml/Y+JUIl64UDmdkboh@kadam/ > Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > --- > V2: > - remove stale spin_unlock() (Oleksandr Tyshchenko) > --- > drivers/xen/pvcalls-front.c | 46 +++++++++++++++++++++---------------- > 1 file changed, 26 insertions(+), 20 deletions(-) > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > index d5d589bda243..b72ee9379d77 100644 > --- a/drivers/xen/pvcalls-front.c > +++ b/drivers/xen/pvcalls-front.c > @@ -227,22 +227,30 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) > > static void free_active_ring(struct sock_mapping *map); > > -static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, > - struct sock_mapping *map) > +static void pvcalls_front_destroy_active(struct pvcalls_bedata *bedata, > + struct sock_mapping *map) > { > int i; > > unbind_from_irqhandler(map->active.irq, map); > > - spin_lock(&bedata->socket_lock); > - if (!list_empty(&map->list)) > - list_del_init(&map->list); > - spin_unlock(&bedata->socket_lock); > + if (bedata) { > + spin_lock(&bedata->socket_lock); > + if (!list_empty(&map->list)) > + list_del_init(&map->list); > + spin_unlock(&bedata->socket_lock); > + } > > for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++) > gnttab_end_foreign_access(map->active.ring->ref[i], NULL); > gnttab_end_foreign_access(map->active.ref, NULL); > free_active_ring(map); > +} > + > +static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, > + struct sock_mapping *map) > +{ > + pvcalls_front_destroy_active(bedata, map); > > kfree(map); > } > @@ -433,19 +441,18 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, > pvcalls_exit_sock(sock); > return ret; > } > - > - spin_lock(&bedata->socket_lock); > - ret = get_request(bedata, &req_id); > + ret = create_active(map, &evtchn); > if (ret < 0) { > - spin_unlock(&bedata->socket_lock); > free_active_ring(map); > pvcalls_exit_sock(sock); > return ret; > } > - ret = create_active(map, &evtchn); > + > + spin_lock(&bedata->socket_lock); > + ret = get_request(bedata, &req_id); > if (ret < 0) { > spin_unlock(&bedata->socket_lock); > - free_active_ring(map); > + pvcalls_front_destroy_active(NULL, map); > pvcalls_exit_sock(sock); > return ret; > } > @@ -821,28 +828,27 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) > pvcalls_exit_sock(sock); > return ret; > } > - spin_lock(&bedata->socket_lock); > - ret = get_request(bedata, &req_id); > + ret = create_active(map2, &evtchn); > if (ret < 0) { > - clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, > - (void *)&map->passive.flags); > - spin_unlock(&bedata->socket_lock); > free_active_ring(map2); > kfree(map2); > + clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, > + (void *)&map->passive.flags); > pvcalls_exit_sock(sock); > return ret; > } > > - ret = create_active(map2, &evtchn); > + spin_lock(&bedata->socket_lock); > + ret = get_request(bedata, &req_id); > if (ret < 0) { > - free_active_ring(map2); > - kfree(map2); > clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, > (void *)&map->passive.flags); > spin_unlock(&bedata->socket_lock); > + pvcalls_front_free_map(bedata, map2); > pvcalls_exit_sock(sock); > return ret; > } > + > list_add_tail(&map2->list, &bedata->socket_mappings); > > req = RING_GET_REQUEST(&bedata->ring, req_id); > -- > 2.35.3 >
On 03.04.23 12:27, Juergen Gross wrote: Hello Juergen > bind_evtchn_to_irqhandler() shouldn't be called under spinlock, as it > can sleep. > > This requires to move the calls of create_active() out of the locked > regions. This is no problem, as the worst which could happen would be > a spurious call of the interrupt handler, causing a spurious wake_up(). > > Reported-by: Dan Carpenter <error27@gmail.com> > Link: https://urldefense.com/v3/__https://lore.kernel.org/lkml/Y*JUIl64UDmdkboh@kadam/__;Kw!!GF_29dbcQIUBPA!wTyU032PQPxqlpIfuWRwb-DYE1K8P0bRWJyJICa7IEbAwQ0_aeZwknAWwxJ_cv_tWGY42f5NPgn6JHtZsiGP$ [lore[.]kernel[.]org] > Signed-off-by: Juergen Gross <jgross@suse.com> > --- > V2: > - remove stale spin_unlock() (Oleksandr Tyshchenko) Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> > --- > drivers/xen/pvcalls-front.c | 46 +++++++++++++++++++++---------------- > 1 file changed, 26 insertions(+), 20 deletions(-) > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > index d5d589bda243..b72ee9379d77 100644 > --- a/drivers/xen/pvcalls-front.c > +++ b/drivers/xen/pvcalls-front.c > @@ -227,22 +227,30 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) > > static void free_active_ring(struct sock_mapping *map); > > -static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, > - struct sock_mapping *map) > +static void pvcalls_front_destroy_active(struct pvcalls_bedata *bedata, > + struct sock_mapping *map) > { > int i; > > unbind_from_irqhandler(map->active.irq, map); > > - spin_lock(&bedata->socket_lock); > - if (!list_empty(&map->list)) > - list_del_init(&map->list); > - spin_unlock(&bedata->socket_lock); > + if (bedata) { > + spin_lock(&bedata->socket_lock); > + if (!list_empty(&map->list)) > + list_del_init(&map->list); > + spin_unlock(&bedata->socket_lock); > + } > > for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++) > gnttab_end_foreign_access(map->active.ring->ref[i], NULL); > gnttab_end_foreign_access(map->active.ref, NULL); > free_active_ring(map); > +} > + > +static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, > + struct sock_mapping *map) > +{ > + pvcalls_front_destroy_active(bedata, map); > > kfree(map); > } > @@ -433,19 +441,18 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, > pvcalls_exit_sock(sock); > return ret; > } > - > - spin_lock(&bedata->socket_lock); > - ret = get_request(bedata, &req_id); > + ret = create_active(map, &evtchn); > if (ret < 0) { > - spin_unlock(&bedata->socket_lock); > free_active_ring(map); > pvcalls_exit_sock(sock); > return ret; > } > - ret = create_active(map, &evtchn); > + > + spin_lock(&bedata->socket_lock); > + ret = get_request(bedata, &req_id); > if (ret < 0) { > spin_unlock(&bedata->socket_lock); > - free_active_ring(map); > + pvcalls_front_destroy_active(NULL, map); > pvcalls_exit_sock(sock); > return ret; > } > @@ -821,28 +828,27 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) > pvcalls_exit_sock(sock); > return ret; > } > - spin_lock(&bedata->socket_lock); > - ret = get_request(bedata, &req_id); > + ret = create_active(map2, &evtchn); > if (ret < 0) { > - clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, > - (void *)&map->passive.flags); > - spin_unlock(&bedata->socket_lock); > free_active_ring(map2); > kfree(map2); > + clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, > + (void *)&map->passive.flags); > pvcalls_exit_sock(sock); > return ret; > } > > - ret = create_active(map2, &evtchn); > + spin_lock(&bedata->socket_lock); > + ret = get_request(bedata, &req_id); > if (ret < 0) { > - free_active_ring(map2); > - kfree(map2); > clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, > (void *)&map->passive.flags); > spin_unlock(&bedata->socket_lock); > + pvcalls_front_free_map(bedata, map2); > pvcalls_exit_sock(sock); > return ret; > } > + > list_add_tail(&map2->list, &bedata->socket_mappings); > > req = RING_GET_REQUEST(&bedata->ring, req_id);
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