aec72f3392
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>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.