| Message ID | 20230328093924.12260-1-jgross@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xen/pvcalls: don't call bind_evtchn_to_irqhandler() under lock | expand |
On 28.03.23 12:39, 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://lore.kernel.org/lkml/Y+JUIl64UDmdkboh@kadam/ > Signed-off-by: Juergen Gross <jgross@suse.com> > --- > drivers/xen/pvcalls-front.c | 46 ++++++++++++++++++++++--------------- > 1 file changed, 27 insertions(+), 19 deletions(-) > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > index d5d589bda243..6e5d712e3115 100644 > --- a/drivers/xen/pvcalls-front.c > +++ b/drivers/xen/pvcalls-front.c > @@ -227,22 +227,31 @@ 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 +442,18 @@ 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 +829,28 @@ 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) { > + free_active_ring(map2); > + kfree(map2); > clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, > (void *)&map->passive.flags); > spin_unlock(&bedata->socket_lock); Looks like we also need to remove spin_unlock() above, correct? > - free_active_ring(map2); > - kfree(map2); > 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);
On 28.03.23 12:34, Oleksandr Tyshchenko wrote: > > > On 28.03.23 12:39, 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://lore.kernel.org/lkml/Y+JUIl64UDmdkboh@kadam/ >> Signed-off-by: Juergen Gross <jgross@suse.com> >> --- >> drivers/xen/pvcalls-front.c | 46 ++++++++++++++++++++++--------------- >> 1 file changed, 27 insertions(+), 19 deletions(-) >> >> diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c >> index d5d589bda243..6e5d712e3115 100644 >> --- a/drivers/xen/pvcalls-front.c >> +++ b/drivers/xen/pvcalls-front.c >> @@ -227,22 +227,31 @@ 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 +442,18 @@ 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 +829,28 @@ 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) { >> + free_active_ring(map2); >> + kfree(map2); >> clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, >> (void *)&map->passive.flags); >> spin_unlock(&bedata->socket_lock); > > > Looks like we also need to remove spin_unlock() above, correct? Thanks for catching! Juergen
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index d5d589bda243..6e5d712e3115 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -227,22 +227,31 @@ 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 +442,18 @@ 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 +829,28 @@ 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) { + free_active_ring(map2); + kfree(map2); 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 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);
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> --- drivers/xen/pvcalls-front.c | 46 ++++++++++++++++++++++--------------- 1 file changed, 27 insertions(+), 19 deletions(-)