linux/drivers/net/tap.c

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#include <linux/etherdevice.h>
#include <linux/if_tap.h>
#include <linux/if_vlan.h>
#include <linux/interrupt.h>
#include <linux/nsproxy.h>
#include <linux/compat.h>
#include <linux/if_tun.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/cache.h>
sched/headers: Move task_struct::signal and task_struct::sighand types and accessors into <linux/sched/signal.h> task_struct::signal and task_struct::sighand are pointers, which would normally make it straightforward to not define those types in sched.h. That is not so, because the types are accompanied by a myriad of APIs (macros and inline functions) that dereference them. Split the types and the APIs out of sched.h and move them into a new header, <linux/sched/signal.h>. With this change sched.h does not know about 'struct signal' and 'struct sighand' anymore, trying to put accessors into sched.h as a test fails the following way: ./include/linux/sched.h: In function ‘test_signal_types’: ./include/linux/sched.h:2461:18: error: dereferencing pointer to incomplete type ‘struct signal_struct’ ^ This reduces the size and complexity of sched.h significantly. Update all headers and .c code that relied on getting the signal handling functionality from <linux/sched.h> to include <linux/sched/signal.h>. The list of affected files in the preparatory patch was partly generated by grepping for the APIs, and partly by doing coverage build testing, both all[yes|mod|def|no]config builds on 64-bit and 32-bit x86, and an array of cross-architecture builds. Nevertheless some (trivial) build breakage is still expected related to rare Kconfig combinations and in-flight patches to various kernel code, but most of it should be handled by this patch. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-02 07:35:14 +00:00
#include <linux/sched/signal.h>
#include <linux/types.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/cdev.h>
#include <linux/idr.h>
#include <linux/fs.h>
#include <linux/uio.h>
#include <net/net_namespace.h>
#include <net/rtnetlink.h>
#include <net/sock.h>
#include <linux/virtio_net.h>
#include <linux/skb_array.h>
#define TAP_IFFEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE)
#define TAP_VNET_LE 0x80000000
#define TAP_VNET_BE 0x40000000
#ifdef CONFIG_TUN_VNET_CROSS_LE
static inline bool tap_legacy_is_little_endian(struct tap_queue *q)
{
return q->flags & TAP_VNET_BE ? false :
virtio_legacy_is_little_endian();
}
static long tap_get_vnet_be(struct tap_queue *q, int __user *sp)
{
int s = !!(q->flags & TAP_VNET_BE);
if (put_user(s, sp))
return -EFAULT;
return 0;
}
static long tap_set_vnet_be(struct tap_queue *q, int __user *sp)
{
int s;
if (get_user(s, sp))
return -EFAULT;
if (s)
q->flags |= TAP_VNET_BE;
else
q->flags &= ~TAP_VNET_BE;
return 0;
}
#else
static inline bool tap_legacy_is_little_endian(struct tap_queue *q)
{
return virtio_legacy_is_little_endian();
}
static long tap_get_vnet_be(struct tap_queue *q, int __user *argp)
{
return -EINVAL;
}
static long tap_set_vnet_be(struct tap_queue *q, int __user *argp)
{
return -EINVAL;
}
#endif /* CONFIG_TUN_VNET_CROSS_LE */
static inline bool tap_is_little_endian(struct tap_queue *q)
{
return q->flags & TAP_VNET_LE ||
tap_legacy_is_little_endian(q);
}
static inline u16 tap16_to_cpu(struct tap_queue *q, __virtio16 val)
{
return __virtio16_to_cpu(tap_is_little_endian(q), val);
}
static inline __virtio16 cpu_to_tap16(struct tap_queue *q, u16 val)
{
return __cpu_to_virtio16(tap_is_little_endian(q), val);
}
static struct proto tap_proto = {
.name = "tap",
.owner = THIS_MODULE,
.obj_size = sizeof(struct tap_queue),
};
#define TAP_NUM_DEVS (1U << MINORBITS)
static LIST_HEAD(major_list);
struct major_info {
struct rcu_head rcu;
dev_t major;
struct idr minor_idr;
spinlock_t minor_lock;
const char *device_name;
struct list_head next;
};
#define GOODCOPY_LEN 128
static const struct proto_ops tap_socket_ops;
#define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO)
#define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG | NETIF_F_FRAGLIST)
static struct tap_dev *tap_dev_get_rcu(const struct net_device *dev)
{
return rcu_dereference(dev->rx_handler_data);
}
/*
* RCU usage:
* The tap_queue and the macvlan_dev are loosely coupled, the
* pointers from one to the other can only be read while rcu_read_lock
* or rtnl is held.
*
* Both the file and the macvlan_dev hold a reference on the tap_queue
* through sock_hold(&q->sk). When the macvlan_dev goes away first,
* q->vlan becomes inaccessible. When the files gets closed,
* tap_get_queue() fails.
*
* There may still be references to the struct sock inside of the
* queue from outbound SKBs, but these never reference back to the
* file or the dev. The data structure is freed through __sk_free
* when both our references and any pending SKBs are gone.
*/
static int tap_enable_queue(struct tap_dev *tap, struct file *file,
struct tap_queue *q)
{
int err = -EINVAL;
ASSERT_RTNL();
if (q->enabled)
goto out;
err = 0;
rcu_assign_pointer(tap->taps[tap->numvtaps], q);
q->queue_index = tap->numvtaps;
q->enabled = true;
tap->numvtaps++;
out:
return err;
}
/* Requires RTNL */
static int tap_set_queue(struct tap_dev *tap, struct file *file,
struct tap_queue *q)
{
if (tap->numqueues == MAX_TAP_QUEUES)
return -EBUSY;
rcu_assign_pointer(q->tap, tap);
rcu_assign_pointer(tap->taps[tap->numvtaps], q);
sock_hold(&q->sk);
q->file = file;
q->queue_index = tap->numvtaps;
q->enabled = true;
file->private_data = q;
list_add_tail(&q->next, &tap->queue_list);
tap->numvtaps++;
tap->numqueues++;
return 0;
}
static int tap_disable_queue(struct tap_queue *q)
{
struct tap_dev *tap;
struct tap_queue *nq;
ASSERT_RTNL();
if (!q->enabled)
return -EINVAL;
tap = rtnl_dereference(q->tap);
if (tap) {
int index = q->queue_index;
BUG_ON(index >= tap->numvtaps);
nq = rtnl_dereference(tap->taps[tap->numvtaps - 1]);
nq->queue_index = index;
rcu_assign_pointer(tap->taps[index], nq);
RCU_INIT_POINTER(tap->taps[tap->numvtaps - 1], NULL);
q->enabled = false;
tap->numvtaps--;
}
return 0;
}
/*
* The file owning the queue got closed, give up both
* the reference that the files holds as well as the
* one from the macvlan_dev if that still exists.
*
* Using the spinlock makes sure that we don't get
* to the queue again after destroying it.
*/
static void tap_put_queue(struct tap_queue *q)
{
struct tap_dev *tap;
rtnl_lock();
tap = rtnl_dereference(q->tap);
if (tap) {
if (q->enabled)
BUG_ON(tap_disable_queue(q));
tap->numqueues--;
RCU_INIT_POINTER(q->tap, NULL);
sock_put(&q->sk);
list_del_init(&q->next);
}
rtnl_unlock();
synchronize_rcu();
sock_put(&q->sk);
}
/*
* Select a queue based on the rxq of the device on which this packet
* arrived. If the incoming device is not mq, calculate a flow hash
* to select a queue. If all fails, find the first available queue.
* Cache vlan->numvtaps since it can become zero during the execution
* of this function.
*/
static struct tap_queue *tap_get_queue(struct tap_dev *tap,
struct sk_buff *skb)
{
struct tap_queue *queue = NULL;
/* Access to taps array is protected by rcu, but access to numvtaps
* isn't. Below we use it to lookup a queue, but treat it as a hint
* and validate that the result isn't NULL - in case we are
* racing against queue removal.
*/
locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-23 21:07:29 +00:00
int numvtaps = READ_ONCE(tap->numvtaps);
__u32 rxq;
if (!numvtaps)
goto out;
if (numvtaps == 1)
goto single;
/* Check if we can use flow to select a queue */
rxq = skb_get_hash(skb);
if (rxq) {
queue = rcu_dereference(tap->taps[rxq % numvtaps]);
goto out;
}
if (likely(skb_rx_queue_recorded(skb))) {
rxq = skb_get_rx_queue(skb);
while (unlikely(rxq >= numvtaps))
rxq -= numvtaps;
queue = rcu_dereference(tap->taps[rxq]);
goto out;
}
single:
queue = rcu_dereference(tap->taps[0]);
out:
return queue;
}
/*
* The net_device is going away, give up the reference
* that it holds on all queues and safely set the pointer
* from the queues to NULL.
*/
void tap_del_queues(struct tap_dev *tap)
{
struct tap_queue *q, *tmp;
ASSERT_RTNL();
list_for_each_entry_safe(q, tmp, &tap->queue_list, next) {
list_del_init(&q->next);
RCU_INIT_POINTER(q->tap, NULL);
if (q->enabled)
tap->numvtaps--;
tap->numqueues--;
sock_put(&q->sk);
}
BUG_ON(tap->numvtaps);
BUG_ON(tap->numqueues);
/* guarantee that any future tap_set_queue will fail */
tap->numvtaps = MAX_TAP_QUEUES;
}
EXPORT_SYMBOL_GPL(tap_del_queues);
rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
{
struct sk_buff *skb = *pskb;
struct net_device *dev = skb->dev;
struct tap_dev *tap;
struct tap_queue *q;
netdev_features_t features = TAP_FEATURES;
tap = tap_dev_get_rcu(dev);
if (!tap)
return RX_HANDLER_PASS;
q = tap_get_queue(tap, skb);
if (!q)
return RX_HANDLER_PASS;
macvtap: Limit packet queue length Mark Wagner reported OOM symptoms when sending UDP traffic over a macvtap link to a kvm receiver. This appears to be caused by the fact that macvtap packet queues are unlimited in length. This means that if the receiver can't keep up with the rate of flow, then we will hit OOM. Of course it gets worse if the OOM killer then decides to kill the receiver. This patch imposes a cap on the packet queue length, in the same way as the tuntap driver, using the device TX queue length. Please note that macvtap currently has no way of giving congestion notification, that means the software device TX queue cannot be used and packets will always be dropped once the macvtap driver queue fills up. This shouldn't be a great problem for the scenario where macvtap is used to feed a kvm receiver, as the traffic is most likely external in origin so congestion notification can't be applied anyway. Of course, if anybody decides to complain about guest-to-guest UDP packet loss down the track, then we may have to revisit this. Incidentally, this patch also fixes a real memory leak when macvtap_get_queue fails. Chris Wright noticed that for this patch to work, we need a non-zero TX queue length. This patch includes his work to change the default macvtap TX queue length to 500. Reported-by: Mark Wagner <mwagner@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Chris Wright <chrisw@sous-sol.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-07-21 21:44:31 +00:00
skb_push(skb, ETH_HLEN);
/* Apply the forward feature mask so that we perform segmentation
* according to users wishes. This only works if VNET_HDR is
* enabled.
*/
if (q->flags & IFF_VNET_HDR)
features |= tap->tap_features;
if (netif_needs_gso(skb, features)) {
struct sk_buff *segs = __skb_gso_segment(skb, features, false);
if (IS_ERR(segs))
goto drop;
if (!segs) {
if (ptr_ring_produce(&q->ring, skb))
goto drop;
goto wake_up;
}
consume_skb(skb);
while (segs) {
struct sk_buff *nskb = segs->next;
segs->next = NULL;
if (ptr_ring_produce(&q->ring, segs)) {
kfree_skb(segs);
kfree_skb_list(nskb);
break;
}
segs = nskb;
}
} else {
/* If we receive a partial checksum and the tap side
* doesn't support checksum offload, compute the checksum.
* Note: it doesn't matter which checksum feature to
* check, we either support them all or none.
*/
if (skb->ip_summed == CHECKSUM_PARTIAL &&
!(features & NETIF_F_CSUM_MASK) &&
skb_checksum_help(skb))
goto drop;
if (ptr_ring_produce(&q->ring, skb))
goto drop;
}
wake_up:
wake_up_interruptible_poll(sk_sleep(&q->sk), EPOLLIN | EPOLLRDNORM | EPOLLRDBAND);
return RX_HANDLER_CONSUMED;
macvtap: Limit packet queue length Mark Wagner reported OOM symptoms when sending UDP traffic over a macvtap link to a kvm receiver. This appears to be caused by the fact that macvtap packet queues are unlimited in length. This means that if the receiver can't keep up with the rate of flow, then we will hit OOM. Of course it gets worse if the OOM killer then decides to kill the receiver. This patch imposes a cap on the packet queue length, in the same way as the tuntap driver, using the device TX queue length. Please note that macvtap currently has no way of giving congestion notification, that means the software device TX queue cannot be used and packets will always be dropped once the macvtap driver queue fills up. This shouldn't be a great problem for the scenario where macvtap is used to feed a kvm receiver, as the traffic is most likely external in origin so congestion notification can't be applied anyway. Of course, if anybody decides to complain about guest-to-guest UDP packet loss down the track, then we may have to revisit this. Incidentally, this patch also fixes a real memory leak when macvtap_get_queue fails. Chris Wright noticed that for this patch to work, we need a non-zero TX queue length. This patch includes his work to change the default macvtap TX queue length to 500. Reported-by: Mark Wagner <mwagner@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Chris Wright <chrisw@sous-sol.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-07-21 21:44:31 +00:00
drop:
/* Count errors/drops only here, thus don't care about args. */
if (tap->count_rx_dropped)
tap->count_rx_dropped(tap);
macvtap: Limit packet queue length Mark Wagner reported OOM symptoms when sending UDP traffic over a macvtap link to a kvm receiver. This appears to be caused by the fact that macvtap packet queues are unlimited in length. This means that if the receiver can't keep up with the rate of flow, then we will hit OOM. Of course it gets worse if the OOM killer then decides to kill the receiver. This patch imposes a cap on the packet queue length, in the same way as the tuntap driver, using the device TX queue length. Please note that macvtap currently has no way of giving congestion notification, that means the software device TX queue cannot be used and packets will always be dropped once the macvtap driver queue fills up. This shouldn't be a great problem for the scenario where macvtap is used to feed a kvm receiver, as the traffic is most likely external in origin so congestion notification can't be applied anyway. Of course, if anybody decides to complain about guest-to-guest UDP packet loss down the track, then we may have to revisit this. Incidentally, this patch also fixes a real memory leak when macvtap_get_queue fails. Chris Wright noticed that for this patch to work, we need a non-zero TX queue length. This patch includes his work to change the default macvtap TX queue length to 500. Reported-by: Mark Wagner <mwagner@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Chris Wright <chrisw@sous-sol.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-07-21 21:44:31 +00:00
kfree_skb(skb);
return RX_HANDLER_CONSUMED;
}
EXPORT_SYMBOL_GPL(tap_handle_frame);
static struct major_info *tap_get_major(int major)
{
struct major_info *tap_major;
list_for_each_entry_rcu(tap_major, &major_list, next) {
if (tap_major->major == major)
return tap_major;
}
return NULL;
}
int tap_get_minor(dev_t major, struct tap_dev *tap)
{
int retval = -ENOMEM;
struct major_info *tap_major;
rcu_read_lock();
tap_major = tap_get_major(MAJOR(major));
if (!tap_major) {
retval = -EINVAL;
goto unlock;
}
spin_lock(&tap_major->minor_lock);
retval = idr_alloc(&tap_major->minor_idr, tap, 1, TAP_NUM_DEVS, GFP_ATOMIC);
if (retval >= 0) {
tap->minor = retval;
} else if (retval == -ENOSPC) {
netdev_err(tap->dev, "Too many tap devices\n");
retval = -EINVAL;
}
spin_unlock(&tap_major->minor_lock);
unlock:
rcu_read_unlock();
return retval < 0 ? retval : 0;
}
EXPORT_SYMBOL_GPL(tap_get_minor);
void tap_free_minor(dev_t major, struct tap_dev *tap)
{
struct major_info *tap_major;
rcu_read_lock();
tap_major = tap_get_major(MAJOR(major));
if (!tap_major) {
goto unlock;
}
spin_lock(&tap_major->minor_lock);
if (tap->minor) {
idr_remove(&tap_major->minor_idr, tap->minor);
tap->minor = 0;
}
spin_unlock(&tap_major->minor_lock);
unlock:
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(tap_free_minor);
static struct tap_dev *dev_get_by_tap_file(int major, int minor)
{
struct net_device *dev = NULL;
struct tap_dev *tap;
struct major_info *tap_major;
rcu_read_lock();
tap_major = tap_get_major(major);
if (!tap_major) {
tap = NULL;
goto unlock;
}
spin_lock(&tap_major->minor_lock);
tap = idr_find(&tap_major->minor_idr, minor);
if (tap) {
dev = tap->dev;
dev_hold(dev);
}
spin_unlock(&tap_major->minor_lock);
unlock:
rcu_read_unlock();
return tap;
}
static void tap_sock_write_space(struct sock *sk)
{
net: sock_def_readable() and friends RCU conversion sk_callback_lock rwlock actually protects sk->sk_sleep pointer, so we need two atomic operations (and associated dirtying) per incoming packet. RCU conversion is pretty much needed : 1) Add a new structure, called "struct socket_wq" to hold all fields that will need rcu_read_lock() protection (currently: a wait_queue_head_t and a struct fasync_struct pointer). [Future patch will add a list anchor for wakeup coalescing] 2) Attach one of such structure to each "struct socket" created in sock_alloc_inode(). 3) Respect RCU grace period when freeing a "struct socket_wq" 4) Change sk_sleep pointer in "struct sock" by sk_wq, pointer to "struct socket_wq" 5) Change sk_sleep() function to use new sk->sk_wq instead of sk->sk_sleep 6) Change sk_has_sleeper() to wq_has_sleeper() that must be used inside a rcu_read_lock() section. 7) Change all sk_has_sleeper() callers to : - Use rcu_read_lock() instead of read_lock(&sk->sk_callback_lock) - Use wq_has_sleeper() to eventually wakeup tasks. - Use rcu_read_unlock() instead of read_unlock(&sk->sk_callback_lock) 8) sock_wake_async() is modified to use rcu protection as well. 9) Exceptions : macvtap, drivers/net/tun.c, af_unix use integrated "struct socket_wq" instead of dynamically allocated ones. They dont need rcu freeing. Some cleanups or followups are probably needed, (possible sk_callback_lock conversion to a spinlock for example...). Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-29 11:01:49 +00:00
wait_queue_head_t *wqueue;
if (!sock_writeable(sk) ||
!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
return;
net: sock_def_readable() and friends RCU conversion sk_callback_lock rwlock actually protects sk->sk_sleep pointer, so we need two atomic operations (and associated dirtying) per incoming packet. RCU conversion is pretty much needed : 1) Add a new structure, called "struct socket_wq" to hold all fields that will need rcu_read_lock() protection (currently: a wait_queue_head_t and a struct fasync_struct pointer). [Future patch will add a list anchor for wakeup coalescing] 2) Attach one of such structure to each "struct socket" created in sock_alloc_inode(). 3) Respect RCU grace period when freeing a "struct socket_wq" 4) Change sk_sleep pointer in "struct sock" by sk_wq, pointer to "struct socket_wq" 5) Change sk_sleep() function to use new sk->sk_wq instead of sk->sk_sleep 6) Change sk_has_sleeper() to wq_has_sleeper() that must be used inside a rcu_read_lock() section. 7) Change all sk_has_sleeper() callers to : - Use rcu_read_lock() instead of read_lock(&sk->sk_callback_lock) - Use wq_has_sleeper() to eventually wakeup tasks. - Use rcu_read_unlock() instead of read_unlock(&sk->sk_callback_lock) 8) sock_wake_async() is modified to use rcu protection as well. 9) Exceptions : macvtap, drivers/net/tun.c, af_unix use integrated "struct socket_wq" instead of dynamically allocated ones. They dont need rcu freeing. Some cleanups or followups are probably needed, (possible sk_callback_lock conversion to a spinlock for example...). Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-29 11:01:49 +00:00
wqueue = sk_sleep(sk);
if (wqueue && waitqueue_active(wqueue))
wake_up_interruptible_poll(wqueue, EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
}
static void tap_sock_destruct(struct sock *sk)
{
struct tap_queue *q = container_of(sk, struct tap_queue, sk);
ptr_ring_cleanup(&q->ring, __skb_array_destroy_skb);
}
static int tap_open(struct inode *inode, struct file *file)
{
struct net *net = current->nsproxy->net_ns;
struct tap_dev *tap;
struct tap_queue *q;
int err = -ENODEV;
rtnl_lock();
tap = dev_get_by_tap_file(imajor(inode), iminor(inode));
if (!tap)
goto err;
err = -ENOMEM;
q = (struct tap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
&tap_proto, 0);
if (!q)
goto err;
if (ptr_ring_init(&q->ring, tap->dev->tx_queue_len, GFP_KERNEL)) {
sk_free(&q->sk);
goto err;
}
RCU_INIT_POINTER(q->sock.wq, &q->wq);
net: sock_def_readable() and friends RCU conversion sk_callback_lock rwlock actually protects sk->sk_sleep pointer, so we need two atomic operations (and associated dirtying) per incoming packet. RCU conversion is pretty much needed : 1) Add a new structure, called "struct socket_wq" to hold all fields that will need rcu_read_lock() protection (currently: a wait_queue_head_t and a struct fasync_struct pointer). [Future patch will add a list anchor for wakeup coalescing] 2) Attach one of such structure to each "struct socket" created in sock_alloc_inode(). 3) Respect RCU grace period when freeing a "struct socket_wq" 4) Change sk_sleep pointer in "struct sock" by sk_wq, pointer to "struct socket_wq" 5) Change sk_sleep() function to use new sk->sk_wq instead of sk->sk_sleep 6) Change sk_has_sleeper() to wq_has_sleeper() that must be used inside a rcu_read_lock() section. 7) Change all sk_has_sleeper() callers to : - Use rcu_read_lock() instead of read_lock(&sk->sk_callback_lock) - Use wq_has_sleeper() to eventually wakeup tasks. - Use rcu_read_unlock() instead of read_unlock(&sk->sk_callback_lock) 8) sock_wake_async() is modified to use rcu protection as well. 9) Exceptions : macvtap, drivers/net/tun.c, af_unix use integrated "struct socket_wq" instead of dynamically allocated ones. They dont need rcu freeing. Some cleanups or followups are probably needed, (possible sk_callback_lock conversion to a spinlock for example...). Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-29 11:01:49 +00:00
init_waitqueue_head(&q->wq.wait);
q->sock.type = SOCK_RAW;
q->sock.state = SS_CONNECTED;
q->sock.file = file;
q->sock.ops = &tap_socket_ops;
sock_init_data(&q->sock, &q->sk);
q->sk.sk_write_space = tap_sock_write_space;
q->sk.sk_destruct = tap_sock_destruct;
q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
q->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
/*
* so far only KVM virtio_net uses tap, enable zero copy between
* guest kernel and host kernel when lower device supports zerocopy
*
* The macvlan supports zerocopy iff the lower device supports zero
* copy so we don't have to look at the lower device directly.
*/
if ((tap->dev->features & NETIF_F_HIGHDMA) && (tap->dev->features & NETIF_F_SG))
sock_set_flag(&q->sk, SOCK_ZEROCOPY);
err = tap_set_queue(tap, file, q);
if (err) {
/* tap_sock_destruct() will take care of freeing ptr_ring */
goto err_put;
}
dev_put(tap->dev);
rtnl_unlock();
return err;
err_put:
sock_put(&q->sk);
err:
if (tap)
dev_put(tap->dev);
rtnl_unlock();
return err;
}
static int tap_release(struct inode *inode, struct file *file)
{
struct tap_queue *q = file->private_data;
tap_put_queue(q);
return 0;
}
static __poll_t tap_poll(struct file *file, poll_table *wait)
{
struct tap_queue *q = file->private_data;
__poll_t mask = EPOLLERR;
if (!q)
goto out;
mask = 0;
net: sock_def_readable() and friends RCU conversion sk_callback_lock rwlock actually protects sk->sk_sleep pointer, so we need two atomic operations (and associated dirtying) per incoming packet. RCU conversion is pretty much needed : 1) Add a new structure, called "struct socket_wq" to hold all fields that will need rcu_read_lock() protection (currently: a wait_queue_head_t and a struct fasync_struct pointer). [Future patch will add a list anchor for wakeup coalescing] 2) Attach one of such structure to each "struct socket" created in sock_alloc_inode(). 3) Respect RCU grace period when freeing a "struct socket_wq" 4) Change sk_sleep pointer in "struct sock" by sk_wq, pointer to "struct socket_wq" 5) Change sk_sleep() function to use new sk->sk_wq instead of sk->sk_sleep 6) Change sk_has_sleeper() to wq_has_sleeper() that must be used inside a rcu_read_lock() section. 7) Change all sk_has_sleeper() callers to : - Use rcu_read_lock() instead of read_lock(&sk->sk_callback_lock) - Use wq_has_sleeper() to eventually wakeup tasks. - Use rcu_read_unlock() instead of read_unlock(&sk->sk_callback_lock) 8) sock_wake_async() is modified to use rcu protection as well. 9) Exceptions : macvtap, drivers/net/tun.c, af_unix use integrated "struct socket_wq" instead of dynamically allocated ones. They dont need rcu freeing. Some cleanups or followups are probably needed, (possible sk_callback_lock conversion to a spinlock for example...). Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-29 11:01:49 +00:00
poll_wait(file, &q->wq.wait, wait);
if (!ptr_ring_empty(&q->ring))
mask |= EPOLLIN | EPOLLRDNORM;
if (sock_writeable(&q->sk) ||
(!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &q->sock.flags) &&
sock_writeable(&q->sk)))
mask |= EPOLLOUT | EPOLLWRNORM;
out:
return mask;
}
static inline struct sk_buff *tap_alloc_skb(struct sock *sk, size_t prepad,
size_t len, size_t linear,
int noblock, int *err)
{
struct sk_buff *skb;
/* Under a page? Don't bother with paged skb. */
if (prepad + len < PAGE_SIZE || !linear)
linear = len;
skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
err, 0);
if (!skb)
return NULL;
skb_reserve(skb, prepad);
skb_put(skb, linear);
skb->data_len = len - linear;
skb->len += len - linear;
return skb;
}
/* Neighbour code has some assumptions on HH_DATA_MOD alignment */
#define TAP_RESERVE HH_DATA_OFF(ETH_HLEN)
/* Get packet from user space buffer */
static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
struct iov_iter *from, int noblock)
{
int good_linear = SKB_MAX_HEAD(TAP_RESERVE);
struct sk_buff *skb;
struct tap_dev *tap;
unsigned long total_len = iov_iter_count(from);
unsigned long len = total_len;
int err;
struct virtio_net_hdr vnet_hdr = { 0 };
int vnet_hdr_len = 0;
int copylen = 0;
int depth;
bool zerocopy = false;
size_t linear;
if (q->flags & IFF_VNET_HDR) {
vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
err = -EINVAL;
if (len < vnet_hdr_len)
goto err;
len -= vnet_hdr_len;
err = -EFAULT;
if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from))
goto err;
iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));
if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
tap16_to_cpu(q, vnet_hdr.csum_start) +
tap16_to_cpu(q, vnet_hdr.csum_offset) + 2 >
tap16_to_cpu(q, vnet_hdr.hdr_len))
vnet_hdr.hdr_len = cpu_to_tap16(q,
tap16_to_cpu(q, vnet_hdr.csum_start) +
tap16_to_cpu(q, vnet_hdr.csum_offset) + 2);
err = -EINVAL;
if (tap16_to_cpu(q, vnet_hdr.hdr_len) > len)
goto err;
}
err = -EINVAL;
if (unlikely(len < ETH_HLEN))
goto err;
if (msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
struct iov_iter i;
copylen = vnet_hdr.hdr_len ?
tap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN;
if (copylen > good_linear)
copylen = good_linear;
else if (copylen < ETH_HLEN)
copylen = ETH_HLEN;
linear = copylen;
i = *from;
iov_iter_advance(&i, copylen);
if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
zerocopy = true;
}
if (!zerocopy) {
copylen = len;
linear = tap16_to_cpu(q, vnet_hdr.hdr_len);
if (linear > good_linear)
linear = good_linear;
else if (linear < ETH_HLEN)
linear = ETH_HLEN;
}
skb = tap_alloc_skb(&q->sk, TAP_RESERVE, copylen,
linear, noblock, &err);
if (!skb)
goto err;
if (zerocopy)
err = zerocopy_sg_from_iter(skb, from);
else
err = skb_copy_datagram_from_iter(skb, 0, from, len);
if (err)
goto err_kfree;
skb_set_network_header(skb, ETH_HLEN);
skb_reset_mac_header(skb);
skb->protocol = eth_hdr(skb)->h_proto;
if (vnet_hdr_len) {
err = virtio_net_hdr_to_skb(skb, &vnet_hdr,
tap_is_little_endian(q));
if (err)
goto err_kfree;
}
skb_probe_transport_header(skb, ETH_HLEN);
/* Move network header to the right position for VLAN tagged packets */
if ((skb->protocol == htons(ETH_P_8021Q) ||
skb->protocol == htons(ETH_P_8021AD)) &&
__vlan_get_protocol(skb, skb->protocol, &depth) != 0)
skb_set_network_header(skb, depth);
rcu_read_lock();
tap = rcu_dereference(q->tap);
/* copy skb_ubuf_info for callback when skb has no error */
if (zerocopy) {
skb_shinfo(skb)->destructor_arg = msg_control;
skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
} else if (msg_control) {
struct ubuf_info *uarg = msg_control;
uarg->callback(uarg, false);
}
if (tap) {
skb->dev = tap->dev;
dev_queue_xmit(skb);
macvtap: fix two races Since commit ac4e4af1e59e1 ("macvtap: Consistently use rcu functions"), Thomas gets two different warnings : BUG: using smp_processor_id() in preemptible [00000000] code: vhost-45891/45892 caller is macvtap_do_read+0x45c/0x600 [macvtap] CPU: 1 PID: 45892 Comm: vhost-45891 Not tainted 3.11.0-bisecttest #13 Call Trace: ([<00000000001126ee>] show_trace+0x126/0x144) [<00000000001127d2>] show_stack+0xc6/0xd4 [<000000000068bcec>] dump_stack+0x74/0xd8 [<0000000000481066>] debug_smp_processor_id+0xf6/0x114 [<000003ff802e9a18>] macvtap_do_read+0x45c/0x600 [macvtap] [<000003ff802e9c1c>] macvtap_recvmsg+0x60/0x88 [macvtap] [<000003ff80318c5e>] handle_rx+0x5b2/0x800 [vhost_net] [<000003ff8028f77c>] vhost_worker+0x15c/0x1c4 [vhost] [<000000000015f3ac>] kthread+0xd8/0xe4 [<00000000006934a6>] kernel_thread_starter+0x6/0xc [<00000000006934a0>] kernel_thread_starter+0x0/0xc And BUG: using smp_processor_id() in preemptible [00000000] code: vhost-45897/45898 caller is macvlan_start_xmit+0x10a/0x1b4 [macvlan] CPU: 1 PID: 45898 Comm: vhost-45897 Not tainted 3.11.0-bisecttest #16 Call Trace: ([<00000000001126ee>] show_trace+0x126/0x144) [<00000000001127d2>] show_stack+0xc6/0xd4 [<000000000068bdb8>] dump_stack+0x74/0xd4 [<0000000000481132>] debug_smp_processor_id+0xf6/0x114 [<000003ff802b72ca>] macvlan_start_xmit+0x10a/0x1b4 [macvlan] [<000003ff802ea69a>] macvtap_get_user+0x982/0xbc4 [macvtap] [<000003ff802ea92a>] macvtap_sendmsg+0x4e/0x60 [macvtap] [<000003ff8031947c>] handle_tx+0x494/0x5ec [vhost_net] [<000003ff8028f77c>] vhost_worker+0x15c/0x1c4 [vhost] [<000000000015f3ac>] kthread+0xd8/0xe4 [<000000000069356e>] kernel_thread_starter+0x6/0xc [<0000000000693568>] kernel_thread_starter+0x0/0xc 2 locks held by vhost-45897/45898: #0: (&vq->mutex){+.+.+.}, at: [<000003ff8031903c>] handle_tx+0x54/0x5ec [vhost_net] #1: (rcu_read_lock){.+.+..}, at: [<000003ff802ea53c>] macvtap_get_user+0x824/0xbc4 [macvtap] In the first case, macvtap_put_user() calls macvlan_count_rx() in a preempt-able context, and this is not allowed. In the second case, macvtap_get_user() calls macvlan_start_xmit() with BH enabled, and this is not allowed. Reported-by: Thomas Huth <thuth@linux.vnet.ibm.com> Bisected-by: Thomas Huth <thuth@linux.vnet.ibm.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Tested-by: Thomas Huth <thuth@linux.vnet.ibm.com> Cc: Vlad Yasevich <vyasevic@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-08 15:06:14 +00:00
} else {
kfree_skb(skb);
macvtap: fix two races Since commit ac4e4af1e59e1 ("macvtap: Consistently use rcu functions"), Thomas gets two different warnings : BUG: using smp_processor_id() in preemptible [00000000] code: vhost-45891/45892 caller is macvtap_do_read+0x45c/0x600 [macvtap] CPU: 1 PID: 45892 Comm: vhost-45891 Not tainted 3.11.0-bisecttest #13 Call Trace: ([<00000000001126ee>] show_trace+0x126/0x144) [<00000000001127d2>] show_stack+0xc6/0xd4 [<000000000068bcec>] dump_stack+0x74/0xd8 [<0000000000481066>] debug_smp_processor_id+0xf6/0x114 [<000003ff802e9a18>] macvtap_do_read+0x45c/0x600 [macvtap] [<000003ff802e9c1c>] macvtap_recvmsg+0x60/0x88 [macvtap] [<000003ff80318c5e>] handle_rx+0x5b2/0x800 [vhost_net] [<000003ff8028f77c>] vhost_worker+0x15c/0x1c4 [vhost] [<000000000015f3ac>] kthread+0xd8/0xe4 [<00000000006934a6>] kernel_thread_starter+0x6/0xc [<00000000006934a0>] kernel_thread_starter+0x0/0xc And BUG: using smp_processor_id() in preemptible [00000000] code: vhost-45897/45898 caller is macvlan_start_xmit+0x10a/0x1b4 [macvlan] CPU: 1 PID: 45898 Comm: vhost-45897 Not tainted 3.11.0-bisecttest #16 Call Trace: ([<00000000001126ee>] show_trace+0x126/0x144) [<00000000001127d2>] show_stack+0xc6/0xd4 [<000000000068bdb8>] dump_stack+0x74/0xd4 [<0000000000481132>] debug_smp_processor_id+0xf6/0x114 [<000003ff802b72ca>] macvlan_start_xmit+0x10a/0x1b4 [macvlan] [<000003ff802ea69a>] macvtap_get_user+0x982/0xbc4 [macvtap] [<000003ff802ea92a>] macvtap_sendmsg+0x4e/0x60 [macvtap] [<000003ff8031947c>] handle_tx+0x494/0x5ec [vhost_net] [<000003ff8028f77c>] vhost_worker+0x15c/0x1c4 [vhost] [<000000000015f3ac>] kthread+0xd8/0xe4 [<000000000069356e>] kernel_thread_starter+0x6/0xc [<0000000000693568>] kernel_thread_starter+0x0/0xc 2 locks held by vhost-45897/45898: #0: (&vq->mutex){+.+.+.}, at: [<000003ff8031903c>] handle_tx+0x54/0x5ec [vhost_net] #1: (rcu_read_lock){.+.+..}, at: [<000003ff802ea53c>] macvtap_get_user+0x824/0xbc4 [macvtap] In the first case, macvtap_put_user() calls macvlan_count_rx() in a preempt-able context, and this is not allowed. In the second case, macvtap_get_user() calls macvlan_start_xmit() with BH enabled, and this is not allowed. Reported-by: Thomas Huth <thuth@linux.vnet.ibm.com> Bisected-by: Thomas Huth <thuth@linux.vnet.ibm.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Tested-by: Thomas Huth <thuth@linux.vnet.ibm.com> Cc: Vlad Yasevich <vyasevic@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-08 15:06:14 +00:00
}
rcu_read_unlock();
return total_len;
err_kfree:
kfree_skb(skb);
err:
rcu_read_lock();
tap = rcu_dereference(q->tap);
if (tap && tap->count_tx_dropped)
tap->count_tx_dropped(tap);
rcu_read_unlock();
return err;
}
static ssize_t tap_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct tap_queue *q = file->private_data;
return tap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK);
}
/* Put packet to the user space buffer */
static ssize_t tap_put_user(struct tap_queue *q,
const struct sk_buff *skb,
struct iov_iter *iter)
{
int ret;
int vnet_hdr_len = 0;
int vlan_offset = 0;
int total;
if (q->flags & IFF_VNET_HDR) {
int vlan_hlen = skb_vlan_tag_present(skb) ? VLAN_HLEN : 0;
struct virtio_net_hdr vnet_hdr;
vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
if (iov_iter_count(iter) < vnet_hdr_len)
return -EINVAL;
if (virtio_net_hdr_from_skb(skb, &vnet_hdr,
tap_is_little_endian(q), true,
vlan_hlen))
BUG();
if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) !=
sizeof(vnet_hdr))
return -EFAULT;
iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr));
}
total = vnet_hdr_len;
total += skb->len;
if (skb_vlan_tag_present(skb)) {
struct {
__be16 h_vlan_proto;
__be16 h_vlan_TCI;
} veth;
veth.h_vlan_proto = skb->vlan_proto;
veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
total += VLAN_HLEN;
ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
if (ret || !iov_iter_count(iter))
goto done;
ret = copy_to_iter(&veth, sizeof(veth), iter);
if (ret != sizeof(veth) || !iov_iter_count(iter))
goto done;
}
ret = skb_copy_datagram_iter(skb, vlan_offset, iter,
skb->len - vlan_offset);
done:
return ret ? ret : total;
}
static ssize_t tap_do_read(struct tap_queue *q,
struct iov_iter *to,
int noblock, struct sk_buff *skb)
{
DEFINE_WAIT(wait);
ssize_t ret = 0;
if (!iov_iter_count(to)) {
kfree_skb(skb);
return 0;
}
if (skb)
goto put;
while (1) {
if (!noblock)
prepare_to_wait(sk_sleep(&q->sk), &wait,
TASK_INTERRUPTIBLE);
/* Read frames from the queue */
skb = ptr_ring_consume(&q->ring);
if (skb)
break;
if (noblock) {
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
/* Nothing to read, let's sleep */
schedule();
}
macvtap: Resolve possible __might_sleep warning in macvtap_do_read() macvtap_do_read code calls macvtap_put_user while it might be set up to wait for the user. This results in the following warning: Jun 23 16:25:26 galen kernel: ------------[ cut here ]------------ Jun 23 16:25:26 galen kernel: WARNING: CPU: 0 PID: 30433 at kernel/sched/core.c: 7286 __might_sleep+0x7f/0x90() Jun 23 16:25:26 galen kernel: do not call blocking ops when !TASK_RUNNING; state =1 set at [<ffffffff810f1c1f>] prepare_to_wait+0x2f/0x90 Jun 23 16:25:26 galen kernel: CPU: 0 PID: 30433 Comm: cat Not tainted 4.1.0-rc6+ #11 Jun 23 16:25:26 galen kernel: Call Trace: Jun 23 16:25:26 galen kernel: [<ffffffff817f76ba>] dump_stack+0x4c/0x65 Jun 23 16:25:26 galen kernel: [<ffffffff810a07ca>] warn_slowpath_common+0x8a/0xc 0 Jun 23 16:25:26 galen kernel: [<ffffffff810a0846>] warn_slowpath_fmt+0x46/0x50 Jun 23 16:25:26 galen kernel: [<ffffffff810f1c1f>] ? prepare_to_wait+0x2f/0x90 Jun 23 16:25:26 galen kernel: [<ffffffff810f1c1f>] ? prepare_to_wait+0x2f/0x90 Jun 23 16:25:26 galen kernel: [<ffffffff810cdc1f>] __might_sleep+0x7f/0x90 Jun 23 16:25:26 galen kernel: [<ffffffff811f8e15>] might_fault+0x55/0xb0 Jun 23 16:25:26 galen kernel: [<ffffffff810fab9d>] ? trace_hardirqs_on_caller+0x fd/0x1c0 Jun 23 16:25:26 galen kernel: [<ffffffff813f639c>] copy_to_iter+0x7c/0x360 Jun 23 16:25:26 galen kernel: [<ffffffffa052da86>] macvtap_do_read+0x256/0x3d0 [macvtap] Jun 23 16:25:26 galen kernel: [<ffffffff810f20e0>] ? prepare_to_wait_event+0x110/0x110 Jun 23 16:25:26 galen kernel: [<ffffffffa052dcab>] macvtap_read_iter+0x2b/0x50 [macvtap] Jun 23 16:25:26 galen kernel: [<ffffffff81247f2e>] __vfs_read+0xae/0xe0 Jun 23 16:25:26 galen kernel: [<ffffffff81248526>] vfs_read+0x86/0x140 Jun 23 16:25:26 galen kernel: [<ffffffff812493b9>] SyS_read+0x49/0xb0 Jun 23 16:25:26 galen kernel: [<ffffffff8180182e>] system_call_fastpath+0x12/0x76 Jun 23 16:25:26 galen kernel: ---[ end trace 22e33f67e70c0c2a ]--- Make sure thet we call finish_wait() if we have the skb to process before trying to actually process it. Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-09 14:14:17 +00:00
if (!noblock)
finish_wait(sk_sleep(&q->sk), &wait);
put:
if (skb) {
ret = tap_put_user(q, skb, to);
if (unlikely(ret < 0))
kfree_skb(skb);
else
consume_skb(skb);
}
return ret;
}
static ssize_t tap_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct file *file = iocb->ki_filp;
struct tap_queue *q = file->private_data;
ssize_t len = iov_iter_count(to), ret;
ret = tap_do_read(q, to, file->f_flags & O_NONBLOCK, NULL);
ret = min_t(ssize_t, ret, len);
if (ret > 0)
iocb->ki_pos = ret;
return ret;
}
static struct tap_dev *tap_get_tap_dev(struct tap_queue *q)
{
struct tap_dev *tap;
ASSERT_RTNL();
tap = rtnl_dereference(q->tap);
if (tap)
dev_hold(tap->dev);
return tap;
}
static void tap_put_tap_dev(struct tap_dev *tap)
{
dev_put(tap->dev);
}
static int tap_ioctl_set_queue(struct file *file, unsigned int flags)
{
struct tap_queue *q = file->private_data;
struct tap_dev *tap;
int ret;
tap = tap_get_tap_dev(q);
if (!tap)
return -EINVAL;
if (flags & IFF_ATTACH_QUEUE)
ret = tap_enable_queue(tap, file, q);
else if (flags & IFF_DETACH_QUEUE)
ret = tap_disable_queue(q);
else
ret = -EINVAL;
tap_put_tap_dev(tap);
return ret;
}
static int set_offload(struct tap_queue *q, unsigned long arg)
{
struct tap_dev *tap;
netdev_features_t features;
netdev_features_t feature_mask = 0;
tap = rtnl_dereference(q->tap);
if (!tap)
return -ENOLINK;
features = tap->dev->features;
if (arg & TUN_F_CSUM) {
feature_mask = NETIF_F_HW_CSUM;
if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) {
if (arg & TUN_F_TSO_ECN)
feature_mask |= NETIF_F_TSO_ECN;
if (arg & TUN_F_TSO4)
feature_mask |= NETIF_F_TSO;
if (arg & TUN_F_TSO6)
feature_mask |= NETIF_F_TSO6;
}
}
/* tun/tap driver inverts the usage for TSO offloads, where
* setting the TSO bit means that the userspace wants to
* accept TSO frames and turning it off means that user space
* does not support TSO.
* For tap, we have to invert it to mean the same thing.
* When user space turns off TSO, we turn off GSO/LRO so that
* user-space will not receive TSO frames.
*/
if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6))
features |= RX_OFFLOADS;
else
features &= ~RX_OFFLOADS;
/* tap_features are the same as features on tun/tap and
* reflect user expectations.
*/
tap->tap_features = feature_mask;
if (tap->update_features)
tap->update_features(tap, features);
return 0;
}
/*
* provide compatibility with generic tun/tap interface
*/
static long tap_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct tap_queue *q = file->private_data;
struct tap_dev *tap;
void __user *argp = (void __user *)arg;
struct ifreq __user *ifr = argp;
unsigned int __user *up = argp;
unsigned short u;
int __user *sp = argp;
struct sockaddr sa;
int s;
int ret;
switch (cmd) {
case TUNSETIFF:
/* ignore the name, just look at flags */
if (get_user(u, &ifr->ifr_flags))
return -EFAULT;
ret = 0;
if ((u & ~TAP_IFFEATURES) != (IFF_NO_PI | IFF_TAP))
ret = -EINVAL;
else
q->flags = (q->flags & ~TAP_IFFEATURES) | u;
return ret;
case TUNGETIFF:
rtnl_lock();
tap = tap_get_tap_dev(q);
if (!tap) {
rtnl_unlock();
return -ENOLINK;
}
ret = 0;
u = q->flags;
if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) ||
put_user(u, &ifr->ifr_flags))
ret = -EFAULT;
tap_put_tap_dev(tap);
rtnl_unlock();
return ret;
case TUNSETQUEUE:
if (get_user(u, &ifr->ifr_flags))
return -EFAULT;
rtnl_lock();
ret = tap_ioctl_set_queue(file, u);
rtnl_unlock();
return ret;
case TUNGETFEATURES:
if (put_user(IFF_TAP | IFF_NO_PI | TAP_IFFEATURES, up))
return -EFAULT;
return 0;
case TUNSETSNDBUF:
if (get_user(s, sp))
return -EFAULT;
tun/tap: sanitize TUNSETSNDBUF input Syzkaller found several variants of the lockup below by setting negative values with the TUNSETSNDBUF ioctl. This patch adds a sanity check to both the tun and tap versions of this ioctl. watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [repro:2389] Modules linked in: irq event stamp: 329692056 hardirqs last enabled at (329692055): [<ffffffff824b8381>] _raw_spin_unlock_irqrestore+0x31/0x75 hardirqs last disabled at (329692056): [<ffffffff824b9e58>] apic_timer_interrupt+0x98/0xb0 softirqs last enabled at (35659740): [<ffffffff824bc958>] __do_softirq+0x328/0x48c softirqs last disabled at (35659731): [<ffffffff811c796c>] irq_exit+0xbc/0xd0 CPU: 0 PID: 2389 Comm: repro Not tainted 4.14.0-rc7 #23 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff880009452140 task.stack: ffff880006a20000 RIP: 0010:_raw_spin_lock_irqsave+0x11/0x80 RSP: 0018:ffff880006a27c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10 RAX: ffff880009ac68d0 RBX: ffff880006a27ce0 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffff880006a27ce0 RDI: ffff880009ac6900 RBP: ffff880006a27c60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 000000000063ff00 R12: ffff880009ac6900 R13: ffff880006a27cf8 R14: 0000000000000001 R15: ffff880006a27cf8 FS: 00007f4be4838700(0000) GS:ffff88000cc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020101000 CR3: 0000000009616000 CR4: 00000000000006f0 Call Trace: prepare_to_wait+0x26/0xc0 sock_alloc_send_pskb+0x14e/0x270 ? remove_wait_queue+0x60/0x60 tun_get_user+0x2cc/0x19d0 ? __tun_get+0x60/0x1b0 tun_chr_write_iter+0x57/0x86 __vfs_write+0x156/0x1e0 vfs_write+0xf7/0x230 SyS_write+0x57/0xd0 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x7f4be4356df9 RSP: 002b:00007ffc18101c08 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4be4356df9 RDX: 0000000000000046 RSI: 0000000020101000 RDI: 0000000000000005 RBP: 00007ffc18101c40 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000293 R12: 0000559c75f64780 R13: 00007ffc18101d30 R14: 0000000000000000 R15: 0000000000000000 Fixes: 33dccbb050bb ("tun: Limit amount of queued packets per device") Fixes: 20d29d7a916a ("net: macvtap driver") Signed-off-by: Craig Gallek <kraig@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-30 22:50:11 +00:00
if (s <= 0)
return -EINVAL;
q->sk.sk_sndbuf = s;
return 0;
case TUNGETVNETHDRSZ:
s = q->vnet_hdr_sz;
if (put_user(s, sp))
return -EFAULT;
return 0;
case TUNSETVNETHDRSZ:
if (get_user(s, sp))
return -EFAULT;
if (s < (int)sizeof(struct virtio_net_hdr))
return -EINVAL;
q->vnet_hdr_sz = s;
return 0;
case TUNGETVNETLE:
s = !!(q->flags & TAP_VNET_LE);
if (put_user(s, sp))
return -EFAULT;
return 0;
case TUNSETVNETLE:
if (get_user(s, sp))
return -EFAULT;
if (s)
q->flags |= TAP_VNET_LE;
else
q->flags &= ~TAP_VNET_LE;
return 0;
case TUNGETVNETBE:
return tap_get_vnet_be(q, sp);
case TUNSETVNETBE:
return tap_set_vnet_be(q, sp);
case TUNSETOFFLOAD:
/* let the user check for future flags */
if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
net: accept UFO datagrams from tuntap and packet Tuntap and similar devices can inject GSO packets. Accept type VIRTIO_NET_HDR_GSO_UDP, even though not generating UFO natively. Processes are expected to use feature negotiation such as TUNSETOFFLOAD to detect supported offload types and refrain from injecting other packets. This process breaks down with live migration: guest kernels do not renegotiate flags, so destination hosts need to expose all features that the source host does. Partially revert the UFO removal from 182e0b6b5846~1..d9d30adf5677. This patch introduces nearly(*) no new code to simplify verification. It brings back verbatim tuntap UFO negotiation, VIRTIO_NET_HDR_GSO_UDP insertion and software UFO segmentation. It does not reinstate protocol stack support, hardware offload (NETIF_F_UFO), SKB_GSO_UDP tunneling in SKB_GSO_SOFTWARE or reception of VIRTIO_NET_HDR_GSO_UDP packets in tuntap. To support SKB_GSO_UDP reappearing in the stack, also reinstate logic in act_csum and openvswitch. Achieve equivalence with v4.13 HEAD by squashing in commit 939912216fa8 ("net: skb_needs_check() removes CHECKSUM_UNNECESSARY check for tx.") and reverting commit 8d63bee643f1 ("net: avoid skb_warn_bad_offload false positives on UFO"). (*) To avoid having to bring back skb_shinfo(skb)->ip6_frag_id, ipv6_proxy_select_ident is changed to return a __be32 and this is assigned directly to the frag_hdr. Also, SKB_GSO_UDP is inserted at the end of the enum to minimize code churn. Tested Booted a v4.13 guest kernel with QEMU. On a host kernel before this patch `ethtool -k eth0` shows UFO disabled. After the patch, it is enabled, same as on a v4.13 host kernel. A UFO packet sent from the guest appears on the tap device: host: nc -l -p -u 8000 & tcpdump -n -i tap0 guest: dd if=/dev/zero of=payload.txt bs=1 count=2000 nc -u 192.16.1.1 8000 < payload.txt Direct tap to tap transmission of VIRTIO_NET_HDR_GSO_UDP succeeds, packets arriving fragmented: ./with_tap_pair.sh ./tap_send_ufo tap0 tap1 (from https://github.com/wdebruij/kerneltools/tree/master/tests) Changes v1 -> v2 - simplified set_offload change (review comment) - documented test procedure Link: http://lkml.kernel.org/r/<CAF=yD-LuUeDuL9YWPJD9ykOZ0QCjNeznPDr6whqZ9NGMNF12Mw@mail.gmail.com> Fixes: fb652fdfe837 ("macvlan/macvtap: Remove NETIF_F_UFO advertisement.") Reported-by: Michal Kubecek <mkubecek@suse.cz> Signed-off-by: Willem de Bruijn <willemb@google.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-21 15:22:25 +00:00
TUN_F_TSO_ECN | TUN_F_UFO))
return -EINVAL;
rtnl_lock();
ret = set_offload(q, arg);
rtnl_unlock();
return ret;
case SIOCGIFHWADDR:
rtnl_lock();
tap = tap_get_tap_dev(q);
if (!tap) {
rtnl_unlock();
return -ENOLINK;
}
ret = 0;
u = tap->dev->type;
if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) ||
copy_to_user(&ifr->ifr_hwaddr.sa_data, tap->dev->dev_addr, ETH_ALEN) ||
put_user(u, &ifr->ifr_hwaddr.sa_family))
ret = -EFAULT;
tap_put_tap_dev(tap);
rtnl_unlock();
return ret;
case SIOCSIFHWADDR:
if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa)))
return -EFAULT;
rtnl_lock();
tap = tap_get_tap_dev(q);
if (!tap) {
rtnl_unlock();
return -ENOLINK;
}
ret = dev_set_mac_address(tap->dev, &sa);
tap_put_tap_dev(tap);
rtnl_unlock();
return ret;
default:
return -EINVAL;
}
}
#ifdef CONFIG_COMPAT
static long tap_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
return tap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif
static const struct file_operations tap_fops = {
.owner = THIS_MODULE,
.open = tap_open,
.release = tap_release,
.read_iter = tap_read_iter,
.write_iter = tap_write_iter,
.poll = tap_poll,
.llseek = no_llseek,
.unlocked_ioctl = tap_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = tap_compat_ioctl,
#endif
};
static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp)
{
struct tun_xdp_hdr *hdr = xdp->data_hard_start;
struct virtio_net_hdr *gso = &hdr->gso;
int buflen = hdr->buflen;
int vnet_hdr_len = 0;
struct tap_dev *tap;
struct sk_buff *skb;
int err, depth;
if (q->flags & IFF_VNET_HDR)
vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
skb = build_skb(xdp->data_hard_start, buflen);
if (!skb) {
err = -ENOMEM;
goto err;
}
skb_reserve(skb, xdp->data - xdp->data_hard_start);
skb_put(skb, xdp->data_end - xdp->data);
skb_set_network_header(skb, ETH_HLEN);
skb_reset_mac_header(skb);
skb->protocol = eth_hdr(skb)->h_proto;
if (vnet_hdr_len) {
err = virtio_net_hdr_to_skb(skb, gso, tap_is_little_endian(q));
if (err)
goto err_kfree;
}
skb_probe_transport_header(skb, ETH_HLEN);
/* Move network header to the right position for VLAN tagged packets */
if ((skb->protocol == htons(ETH_P_8021Q) ||
skb->protocol == htons(ETH_P_8021AD)) &&
__vlan_get_protocol(skb, skb->protocol, &depth) != 0)
skb_set_network_header(skb, depth);
rcu_read_lock();
tap = rcu_dereference(q->tap);
if (tap) {
skb->dev = tap->dev;
dev_queue_xmit(skb);
} else {
kfree_skb(skb);
}
rcu_read_unlock();
return 0;
err_kfree:
kfree_skb(skb);
err:
rcu_read_lock();
tap = rcu_dereference(q->tap);
if (tap && tap->count_tx_dropped)
tap->count_tx_dropped(tap);
rcu_read_unlock();
return err;
}
static int tap_sendmsg(struct socket *sock, struct msghdr *m,
size_t total_len)
{
struct tap_queue *q = container_of(sock, struct tap_queue, sock);
struct tun_msg_ctl *ctl = m->msg_control;
struct xdp_buff *xdp;
int i;
if (ctl && (ctl->type == TUN_MSG_PTR)) {
for (i = 0; i < ctl->num; i++) {
xdp = &((struct xdp_buff *)ctl->ptr)[i];
tap_get_user_xdp(q, xdp);
}
return 0;
}
return tap_get_user(q, ctl ? ctl->ptr : NULL, &m->msg_iter,
m->msg_flags & MSG_DONTWAIT);
}
static int tap_recvmsg(struct socket *sock, struct msghdr *m,
size_t total_len, int flags)
{
struct tap_queue *q = container_of(sock, struct tap_queue, sock);
struct sk_buff *skb = m->msg_control;
int ret;
if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) {
kfree_skb(skb);
return -EINVAL;
}
ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT, skb);
if (ret > total_len) {
m->msg_flags |= MSG_TRUNC;
ret = flags & MSG_TRUNC ? ret : total_len;
}
return ret;
}
static int tap_peek_len(struct socket *sock)
{
struct tap_queue *q = container_of(sock, struct tap_queue,
sock);
return PTR_RING_PEEK_CALL(&q->ring, __skb_array_len_with_tag);
}
/* Ops structure to mimic raw sockets with tun */
static const struct proto_ops tap_socket_ops = {
.sendmsg = tap_sendmsg,
.recvmsg = tap_recvmsg,
.peek_len = tap_peek_len,
};
/* Get an underlying socket object from tun file. Returns error unless file is
* attached to a device. The returned object works like a packet socket, it
* can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
* holding a reference to the file for as long as the socket is in use. */
struct socket *tap_get_socket(struct file *file)
{
struct tap_queue *q;
if (file->f_op != &tap_fops)
return ERR_PTR(-EINVAL);
q = file->private_data;
if (!q)
return ERR_PTR(-EBADFD);
return &q->sock;
}
EXPORT_SYMBOL_GPL(tap_get_socket);
struct ptr_ring *tap_get_ptr_ring(struct file *file)
{
struct tap_queue *q;
if (file->f_op != &tap_fops)
return ERR_PTR(-EINVAL);
q = file->private_data;
if (!q)
return ERR_PTR(-EBADFD);
return &q->ring;
}
EXPORT_SYMBOL_GPL(tap_get_ptr_ring);
int tap_queue_resize(struct tap_dev *tap)
{
struct net_device *dev = tap->dev;
struct tap_queue *q;
struct ptr_ring **rings;
int n = tap->numqueues;
int ret, i = 0;
rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
if (!rings)
return -ENOMEM;
list_for_each_entry(q, &tap->queue_list, next)
rings[i++] = &q->ring;
ret = ptr_ring_resize_multiple(rings, n,
dev->tx_queue_len, GFP_KERNEL,
__skb_array_destroy_skb);
kfree(rings);
return ret;
}
EXPORT_SYMBOL_GPL(tap_queue_resize);
static int tap_list_add(dev_t major, const char *device_name)
{
struct major_info *tap_major;
tap_major = kzalloc(sizeof(*tap_major), GFP_ATOMIC);
if (!tap_major)
return -ENOMEM;
tap_major->major = MAJOR(major);
idr_init(&tap_major->minor_idr);
spin_lock_init(&tap_major->minor_lock);
tap_major->device_name = device_name;
list_add_tail_rcu(&tap_major->next, &major_list);
return 0;
}
tap: reference to KVA of an unloaded module causes kernel panic The commit 9a393b5d5988 ("tap: tap as an independent module") created a separate tap module that implements tap functionality and exports interfaces that will be used by macvtap and ipvtap modules to create create respective tap devices. However, that patch introduced a regression wherein the modules macvtap and ipvtap can be removed (through modprobe -r) while there are applications using the respective /dev/tapX devices. These applications cause kernel to hold reference to /dev/tapX through 'struct cdev macvtap_cdev' and 'struct cdev ipvtap_dev' defined in macvtap and ipvtap modules respectively. So, when the application is later closed the kernel panics because we are referencing KVA that is present in the unloaded modules. ----------8<------- Example ----------8<---------- $ sudo ip li add name mv0 link enp7s0 type macvtap $ sudo ip li show mv0 |grep mv0| awk -e '{print $1 $2}' 14:mv0@enp7s0: $ cat /dev/tap14 & $ lsmod |egrep -i 'tap|vlan' macvtap 16384 0 macvlan 24576 1 macvtap tap 24576 3 macvtap $ sudo modprobe -r macvtap $ fg cat /dev/tap14 ^C <...system panics...> BUG: unable to handle kernel paging request at ffffffffa038c500 IP: cdev_put+0xf/0x30 ----------8<-----------------8<---------- The fix is to set cdev.owner to the module that creates the tap device (either macvtap or ipvtap). With this set, the operations (in fs/char_dev.c) on char device holds and releases the module through cdev_get() and cdev_put() and will not allow the module to unload prematurely. Fixes: 9a393b5d5988ea4e (tap: tap as an independent module) Signed-off-by: Girish Moodalbail <girish.moodalbail@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 07:00:16 +00:00
int tap_create_cdev(struct cdev *tap_cdev, dev_t *tap_major,
const char *device_name, struct module *module)
{
int err;
err = alloc_chrdev_region(tap_major, 0, TAP_NUM_DEVS, device_name);
if (err)
goto out1;
cdev_init(tap_cdev, &tap_fops);
tap: reference to KVA of an unloaded module causes kernel panic The commit 9a393b5d5988 ("tap: tap as an independent module") created a separate tap module that implements tap functionality and exports interfaces that will be used by macvtap and ipvtap modules to create create respective tap devices. However, that patch introduced a regression wherein the modules macvtap and ipvtap can be removed (through modprobe -r) while there are applications using the respective /dev/tapX devices. These applications cause kernel to hold reference to /dev/tapX through 'struct cdev macvtap_cdev' and 'struct cdev ipvtap_dev' defined in macvtap and ipvtap modules respectively. So, when the application is later closed the kernel panics because we are referencing KVA that is present in the unloaded modules. ----------8<------- Example ----------8<---------- $ sudo ip li add name mv0 link enp7s0 type macvtap $ sudo ip li show mv0 |grep mv0| awk -e '{print $1 $2}' 14:mv0@enp7s0: $ cat /dev/tap14 & $ lsmod |egrep -i 'tap|vlan' macvtap 16384 0 macvlan 24576 1 macvtap tap 24576 3 macvtap $ sudo modprobe -r macvtap $ fg cat /dev/tap14 ^C <...system panics...> BUG: unable to handle kernel paging request at ffffffffa038c500 IP: cdev_put+0xf/0x30 ----------8<-----------------8<---------- The fix is to set cdev.owner to the module that creates the tap device (either macvtap or ipvtap). With this set, the operations (in fs/char_dev.c) on char device holds and releases the module through cdev_get() and cdev_put() and will not allow the module to unload prematurely. Fixes: 9a393b5d5988ea4e (tap: tap as an independent module) Signed-off-by: Girish Moodalbail <girish.moodalbail@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 07:00:16 +00:00
tap_cdev->owner = module;
err = cdev_add(tap_cdev, *tap_major, TAP_NUM_DEVS);
if (err)
goto out2;
err = tap_list_add(*tap_major, device_name);
if (err)
goto out3;
return 0;
out3:
cdev_del(tap_cdev);
out2:
unregister_chrdev_region(*tap_major, TAP_NUM_DEVS);
out1:
return err;
}
EXPORT_SYMBOL_GPL(tap_create_cdev);
void tap_destroy_cdev(dev_t major, struct cdev *tap_cdev)
{
struct major_info *tap_major, *tmp;
cdev_del(tap_cdev);
unregister_chrdev_region(major, TAP_NUM_DEVS);
list_for_each_entry_safe(tap_major, tmp, &major_list, next) {
if (tap_major->major == MAJOR(major)) {
idr_destroy(&tap_major->minor_idr);
list_del_rcu(&tap_major->next);
kfree_rcu(tap_major, rcu);
}
}
}
EXPORT_SYMBOL_GPL(tap_destroy_cdev);
MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
MODULE_AUTHOR("Sainath Grandhi <sainath.grandhi@intel.com>");
MODULE_LICENSE("GPL");