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Subject: Re: [BUG] rtlwifi: a crash in error handling code of rtl_pci_probe()
To:     Larry Finger <Larry.Finger@lwfinger.net>, pkshih@realtek.com,
        Kalle Valo <kvalo@codeaurora.org>,
        David Miller <davem@davemloft.net>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>
References: <4627da7a-c56c-5d88-62ae-ea2be9430f6f@gmail.com>
 <12810ae7-ff10-42be-7887-19b68331980c@lwfinger.net>
From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Message-ID: <e7f9e9d3-1eac-0d09-104e-209210c3e39c@gmail.com>
Date:   Wed, 15 May 2019 09:20:09 +0800
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On 2019/5/15 9:08, Larry Finger wrote:
> On 5/14/19 8:07 AM, Jia-Ju Bai wrote:
>> In rtl_pci_probe(), when request_irq() in rtl_pci_intr_mode_legacy() 
>> in rtl_pci_intr_mode_decide() fails, a crash occurs.
>> The crash information is as follows:
>>
>> [  108.271155] kasan: CONFIG_KASAN_INLINE enabled
>> [  108.271163] kasan: GPF could be caused by NULL-ptr deref or user 
>> memory access
>> ......
>> [  108.271193] RIP: 0010:cfg80211_get_drvinfo+0xce/0x3b0 [cfg80211]
>> ......
>> [  108.271235] Call Trace:
>> [  108.271245]  ethtool_get_drvinfo+0x110/0x640
>> [  108.271255]  ? cfg80211_get_chan_state+0x7e0/0x7e0 [cfg80211]
>> [  108.271261]  ? ethtool_get_settings+0x340/0x340
>> [  108.271268]  ? __read_once_size_nocheck.constprop.7+0x20/0x20
>> [  108.271279]  ? kasan_check_write+0x14/0x20
>> [  108.271284]  dev_ethtool+0x272d/0x4c20
>> [  108.271290]  ? unwind_get_return_address+0x66/0xb0
>> [  108.271299]  ? __save_stack_trace+0x92/0x100
>> [  108.271307]  ? ethtool_get_rxnfc+0x3f0/0x3f0
>> [  108.271316]  ? save_stack+0xa3/0xd0
>> [  108.271323]  ? save_stack+0x43/0xd0
>> [  108.271331]  ? ftrace_graph_ret_addr+0x2d/0x170
>> [  108.271338]  ? ftrace_graph_ret_addr+0x2d/0x170
>> [  108.271346]  ? ftrace_graph_ret_addr+0x2d/0x170
>> [  108.271354]  ? update_stack_state+0x3b2/0x670
>> [  108.271361]  ? update_stack_state+0x3b2/0x670
>> [  108.271370]  ? __read_once_size_nocheck.constprop.7+0x20/0x20
>> [  108.271379]  ? unwind_next_frame.part.5+0x19f/0xa60
>> [  108.271388]  ? bpf_prog_kallsyms_find+0x3e/0x270
>> [  108.271396]  ? is_bpf_text_address+0x1a/0x30
>> [  108.271408]  ? kernel_text_address+0x11d/0x130
>> [  108.271416]  ? __kernel_text_address+0x12/0x40
>> [  108.271423]  ? unwind_get_return_address+0x66/0xb0
>> [  108.271431]  ? __save_stack_trace+0x92/0x100
>> [  108.271440]  ? save_stack+0xa3/0xd0
>> [  108.271448]  ? udp_ioctl+0x35/0xe0
>> [  108.271457]  ? inet_ioctl+0x100/0x320
>> [  108.271466]  ? inet_stream_connect+0xb0/0xb0
>> [  108.271475]  ? alloc_file+0x60/0x480
>> [  108.271483]  ? alloc_file_pseudo+0x19d/0x270
>> [  108.271495]  ? sock_alloc_file+0x51/0x170
>> [  108.271502]  ? __sys_socket+0x12c/0x1f0
>> [  108.271510]  ? __x64_sys_socket+0x78/0xb0
>> [  108.271520]  ? do_syscall_64+0xb1/0x2e0
>> [  108.271529]  ? entry_SYSCALL_64_after_hwframe+0x44/0xa9
>> [  108.271538]  ? kasan_check_read+0x11/0x20
>> [  108.271548]  ? mutex_lock+0x8f/0xe0
>> [  108.271557]  ? __mutex_lock_slowpath+0x20/0x20
>> [  108.271568]  dev_ioctl+0x1fb/0xae0
>> [  108.271576]  ? dev_ioctl+0x1fb/0xae0
>> [  108.271586]  ? _copy_from_user+0x71/0xd0
>> [  108.271594]  sock_do_ioctl+0x1e2/0x2f0
>> [  108.271602]  ? kmem_cache_alloc+0xf9/0x250
>> [  108.271611]  ? ___sys_recvmsg+0x5a0/0x5a0
>> [  108.271621]  ? apparmor_file_alloc_security+0x128/0x7e0
>> [  108.271630]  ? kasan_unpoison_shadow+0x35/0x50
>> [  108.271638]  ? kasan_kmalloc+0xad/0xe0
>> [  108.271652]  ? apparmor_file_alloc_security+0x128/0x7e0
>> [  108.271662]  ? apparmor_file_alloc_security+0x269/0x7e0
>> [  108.271670]  sock_ioctl+0x361/0x590
>> [  108.271678]  ? sock_ioctl+0x361/0x590
>> [  108.271686]  ? routing_ioctl+0x470/0x470
>> [  108.271695]  ? kasan_check_write+0x14/0x20
>> [  108.271703]  ? __mutex_init+0xba/0x130
>> [  108.271713]  ? percpu_counter_add_batch+0xc7/0x120
>> [  108.271722]  ? alloc_empty_file+0xae/0x150
>> [  108.271729]  ? routing_ioctl+0x470/0x470
>> [  108.271738]  do_vfs_ioctl+0x1ae/0xfe0
>> [  108.271745]  ? do_vfs_ioctl+0x1ae/0xfe0
>> [  108.271754]  ? alloc_file_pseudo+0x1ad/0x270
>> [  108.271762]  ? ioctl_preallocate+0x1e0/0x1e0
>> [  108.271770]  ? alloc_file+0x480/0x480
>> [  108.271778]  ? kasan_check_read+0x11/0x20
>> [  108.271786]  ? __fget+0x24d/0x320
>> [  108.271794]  ? iterate_fd+0x180/0x180
>> [  108.271802]  ? fd_install+0x52/0x60
>> [  108.271812]  ? security_file_ioctl+0x8c/0xb0
>> [  108.271820]  ksys_ioctl+0x99/0xb0
>> [  108.271829]  __x64_sys_ioctl+0x78/0xb0
>> [  108.271839]  do_syscall_64+0xb1/0x2e0
>> [  108.271857]  ? prepare_exit_to_usermode+0xc8/0x160
>> [  108.271871]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
>> ......
>>
>> I checked the driver source code, but cannot find the reason, so I 
>> only report the crash...
>> Can somebody give an explanation about this crash?
>>
>> This crash is triggered by a runtime fuzzing tool named FIZZER 
>> written by us.
>
> Your backtrace does not include any references to rtlwifi routines, 
> and I have no idea what FIZZER does, thus it is not possible for me to 
> debug this. If the error situation that you state happens, the code 
> should end up at label "fail3" in routine rtl_pci_probe(). Insert 
> printk statements after every line of the following, and report the 
> last good point before the error. It is certainly possible that 
> something is being torn down that was never erected. The likelihood of 
> failure of both MSI and legacy interrupts is not very likely, and we 
> probably have never hit those conditions.
>
> fail3:
>         pci_set_drvdata(pdev, NULL);
>         rtl_deinit_core(hw);
>
> fail2:
>         if (rtlpriv->io.pci_mem_start != 0)
>                 pci_iounmap(pdev, (void __iomem 
> *)rtlpriv->io.pci_mem_start);
>
>         pci_release_regions(pdev);
>         complete(&rtlpriv->firmware_loading_complete);
>
> fail1:
>         if (hw)
>                 ieee80211_free_hw(hw);
>         pci_disable_device(pdev);
>
>         return err;

Thanks for the advice :)
I will insert some printk statements to debug this problem.


Best wishes,
Jia-Ju Bai