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| author |   Eric Dumazet <edumazet@google.com> | 2017-10-18 12:12:09 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2017-10-20 13:31:26 +0100 |
| commit | aec72f3392b1d598a979e89c4fdb131965ae0ab3 (patch) | |
| tree | f973f9a1a18d45cd66e7fa6e2be664c298329632 /drivers/net/tun.c | |
| parent | net: ipv4: Change fib notifiers to take a fib_alias (diff) | |
| download | linux-dev-aec72f3392b1d598a979e89c4fdb131965ae0ab3.tar.xz linux-dev-aec72f3392b1d598a979e89c4fdb131965ae0ab3.zip | |
net-tun: fix panics at dismantle time
syzkaller got crashes at dismantle time [1]
It is not correct to test (tun->flags & IFF_NAPI) in tun_napi_disable()
and tun_napi_del() : Each tun_file can have different mode, depending
on how they were created.
Similarly I have changed tun_get_user() and tun_poll_controller()
to use the new tfile->napi_enabled boolean.
[ 154.331360] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 154.339220] IP: [<ffffffff9634cad6>] hrtimer_active+0x26/0x60
[ 154.344983] PGD 0
[ 154.347009] Oops: 0000 [#1] SMP
[ 154.350680] gsmi: Log Shutdown Reason 0x03
[ 154.379572] task: ffff994719150dc0 ti: ffff99475c0ae000 task.ti: ffff99475c0ae000
[ 154.387043] RIP: 0010:[<ffffffff9634cad6>] [<ffffffff9634cad6>] hrtimer_active+0x26/0x60
[ 154.395232] RSP: 0018:ffff99475c0afce8 EFLAGS: 00010246
[ 154.400542] RAX: ffff994754850ac0 RBX: ffff994753e65408 RCX: ffff994753e65388
[ 154.407666] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff994753e65408
[ 154.414790] RBP: ffff99475c0afce8 R08: 0000000000000000 R09: 0000000000000000
[ 154.421921] R10: ffff99475f6f5910 R11: 0000000000000001 R12: 0000000000000000
[ 154.429044] R13: ffff99417deab668 R14: ffff99417deaa780 R15: ffff99475f45dde0
[ 154.436174] FS: 0000000000000000(0000) GS:ffff994767a00000(0000) knlGS:0000000000000000
[ 154.444249] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 154.449986] CR2: 0000000000000000 CR3: 00000005a8a0e000 CR4: 0000000000022670
[ 154.457110] Stack:
[ 154.459120] ffff99475c0afd28 ffffffff9634d614 1000000000000000 0000000000000000
[ 154.466598] ffffe54240000000 ffff994753e65408 ffff994753e653a8 ffff99417deab668
[ 154.474067] ffff99475c0afd48 ffffffff9634d6fd ffff99474c2be678 ffff994753e65398
[ 154.481537] Call Trace:
[ 154.483985] [<ffffffff9634d614>] hrtimer_try_to_cancel+0x24/0xf0
[ 154.490074] [<ffffffff9634d6fd>] hrtimer_cancel+0x1d/0x30
[ 154.495563] [<ffffffff96860b3c>] napi_disable+0x3c/0x70
[ 154.500875] [<ffffffff9678ae62>] __tun_detach+0xd2/0x360
[ 154.506272] [<ffffffff9678b117>] tun_chr_close+0x27/0x40
[ 154.511669] [<ffffffff9646ebe6>] __fput+0xd6/0x1e0
[ 154.516548] [<ffffffff9646ed3e>] ____fput+0xe/0x10
[ 154.521429] [<ffffffff963035a2>] task_work_run+0x72/0x90
[ 154.526827] [<ffffffff962e9407>] do_exit+0x317/0xb60
[ 154.531879] [<ffffffff962e9c8f>] do_group_exit+0x3f/0xa0
[ 154.537275] [<ffffffff962e9d07>] SyS_exit_group+0x17/0x20
[ 154.542769] [<ffffffff969784be>] entry_SYSCALL_64_fastpath+0x12/0x17
Fixes: 943170998b20 ("net-tun: enable NAPI for TUN/TAP driver")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/tun.c')
| -rw-r--r-- | drivers/net/tun.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index c64ec19af9b7..3b41c36eae90 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -175,6 +175,7 @@ struct tun_file { unsigned int ifindex; }; struct napi_struct napi; + bool napi_enabled; struct mutex napi_mutex; /* Protects access to the above napi */ struct list_head next; struct tun_struct *detached; @@ -276,6 +277,7 @@ static int tun_napi_poll(struct napi_struct *napi, int budget) static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile, bool napi_en) { + tfile->napi_enabled = napi_en; if (napi_en) { netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll, NAPI_POLL_WEIGHT); @@ -286,13 +288,13 @@ static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile, static void tun_napi_disable(struct tun_struct *tun, struct tun_file *tfile) { - if (tun->flags & IFF_NAPI) + if (tfile->napi_enabled) napi_disable(&tfile->napi); } static void tun_napi_del(struct tun_struct *tun, struct tun_file *tfile) { - if (tun->flags & IFF_NAPI) + if (tfile->napi_enabled) netif_napi_del(&tfile->napi); } @@ -1055,7 +1057,8 @@ static void tun_poll_controller(struct net_device *dev) rcu_read_lock(); for (i = 0; i < tun->numqueues; i++) { tfile = rcu_dereference(tun->tfiles[i]); - napi_schedule(&tfile->napi); + if (tfile->napi_enabled) + napi_schedule(&tfile->napi); } rcu_read_unlock(); } @@ -1749,7 +1752,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, napi_gro_frags(&tfile->napi); local_bh_enable(); mutex_unlock(&tfile->napi_mutex); - } else if (tun->flags & IFF_NAPI) { + } else if (tfile->napi_enabled) { struct sk_buff_head *queue = &tfile->sk.sk_write_queue; int queue_len; |