From mboxrd@z Thu Jan 1 00:00:00 1970 From: duoming@zju.edu.cn Subject: Re: [PATCH net-next] ax25: Fix deadlock caused by skb_recv_datagram in ax25_recvmsg Date: Tue, 7 Jun 2022 20:20:35 +0800 (GMT+08:00) Message-ID: <17d6464d.57350.1813e1c1082.Coremail.duoming@zju.edu.cn> References: <20220606162138.81505-1-duoming@zju.edu.cn> Mime-Version: 1.0 Content-Transfer-Encoding: base64 Return-path: In-Reply-To: List-ID: Content-Type: text/plain; charset="us-ascii" To: Eric Dumazet Cc: LKML , jreuter@yaina.de, Ralf Baechle , David Miller , Jakub Kicinski , Paolo Abeni , netdev , linux-hams@vger.kernel.org, thomas@osterried.de SGVsbG8sCgpPbiBNb24sIDYgSnVuIDIwMjIgMTA6MzE6NDkgLTA3MDAgRXJpYyBEdW1hemV0IHdy b3RlOgoKPiBPbiBNb24sIEp1biA2LCAyMDIyIGF0IDk6MjEgQU0gRHVvbWluZyBaaG91IDxkdW9t aW5nQHpqdS5lZHUuY24+IHdyb3RlOgo+ID4KPiA+IFRoZSBza2JfcmVjdl9kYXRhZ3JhbSgpIGlu IGF4MjVfcmVjdm1zZygpIHdpbGwgaG9sZCBsb2NrX3NvY2sKPiA+IGFuZCBibG9jayB1bnRpbCBp dCByZWNlaXZlcyBhIHBhY2tldCBmcm9tIHRoZSByZW1vdGUuIElmIHRoZSBjbGllbnQKPiA+IGRv ZXNuYHQgY29ubmVjdCB0byBzZXJ2ZXIgYW5kIGNhbGxzIHJlYWQoKSBkaXJlY3RseSwgaXQgd2ls bCBub3QKPiA+IHJlY2VpdmUgYW55IHBhY2tldHMgZm9yZXZlci4gQXMgYSByZXN1bHQsIHRoZSBk ZWFkbG9jayB3aWxsIGhhcHBlbi4KPiA+Cj4gPiBUaGUgZmFpbCBsb2cgY2F1c2VkIGJ5IGRlYWRs b2NrIGlzIHNob3duIGJlbG93Ogo+ID4KPiA+IFsgIDg2MS4xMjI2MTJdIElORk86IHRhc2sgYXgy NV9kZWFkbG9jazoxNDggYmxvY2tlZCBmb3IgbW9yZSB0aGFuIDczNyBzZWNvbmRzLgo+ID4gWyAg ODYxLjEyNDU0M10gImVjaG8gMCA+IC9wcm9jL3N5cy9rZXJuZWwvaHVuZ190YXNrX3RpbWVvdXRf c2VjcyIgZGlzYWJsZXMgdGhpcyBtZXNzYWdlLgo+ID4gWyAgODYxLjEyNzc2NF0gQ2FsbCBUcmFj ZToKPiA+IFsgIDg2MS4xMjk2ODhdICA8VEFTSz4KPiA+IFsgIDg2MS4xMzA3NDNdICBfX3NjaGVk dWxlKzB4MmY5LzB4YjIwCj4gPiBbICA4NjEuMTMxNTI2XSAgc2NoZWR1bGUrMHg0OS8weGIwCj4g PiBbICA4NjEuMTMxNjQwXSAgX19sb2NrX3NvY2srMHg5Mi8weDEwMAo+ID4gWyAgODYxLjEzMTY0 MF0gID8gZGVzdHJveV9zY2hlZF9kb21haW5zX3JjdSsweDIwLzB4MjAKPiA+IFsgIDg2MS4xMzE2 NDBdICBsb2NrX3NvY2tfbmVzdGVkKzB4NmUvMHg3MAo+ID4gWyAgODYxLjEzMTY0MF0gIGF4MjVf c2VuZG1zZysweDQ2LzB4NDIwCj4gPiBbICA4NjEuMTM0MzgzXSAgPyBheDI1X3JlY3Ztc2crMHgx ZTAvMHgxZTAKPiA+IFsgIDg2MS4xMzU2NThdICBzb2NrX3NlbmRtc2crMHg1OS8weDYwCj4gPiBb ICA4NjEuMTM2NzkxXSAgX19zeXNfc2VuZHRvKzB4ZTkvMHgxNTAKPiA+IFsgIDg2MS4xMzcyMTJd ICA/IF9fc2NoZWR1bGUrMHgzMDEvMHhiMjAKPiA+IFsgIDg2MS4xMzc3MTBdICA/IF9fZG9fc29m dGlycSsweDRhMi8weDRmZAo+ID4gWyAgODYxLjEzOTE1M10gIF9feDY0X3N5c19zZW5kdG8rMHgy MC8weDMwCj4gPiBbICA4NjEuMTQwMzMwXSAgZG9fc3lzY2FsbF82NCsweDNiLzB4OTAKPiA+IFsg IDg2MS4xNDA3MzFdICBlbnRyeV9TWVNDQUxMXzY0X2FmdGVyX2h3ZnJhbWUrMHg0Ni8weGIwCj4g PiBbICA4NjEuMTQxMjQ5XSBSSVA6IDAwMzM6MHg3ZmRmMDVlZTRmNjQKPiA+IFsgIDg2MS4xNDEy NDldIFJTUDogMDAyYjowMDAwN2ZmZTk1NzcyZmMwIEVGTEFHUzogMDAwMDAyNDYgT1JJR19SQVg6 IDAwMDAwMDAwMDAwMDAwMmMKPiA+IFsgIDg2MS4xNDEyNDldIFJBWDogZmZmZmZmZmZmZmZmZmZk YSBSQlg6IDAwMDA1NjUzMDNhMDEzZjAgUkNYOiAwMDAwN2ZkZjA1ZWU0ZjY0Cj4gPiBbICA4NjEu MTQxMjQ5XSBSRFg6IDAwMDAwMDAwMDAwMDAwMDUgUlNJOiAwMDAwNTY1MzAzYTAxNjc4IFJESTog MDAwMDAwMDAwMDAwMDAwNQo+ID4gWyAgODYxLjE0MTI0OV0gUkJQOiAwMDAwMDAwMDAwMDAwMDAw IFIwODogMDAwMDAwMDAwMDAwMDAwMCBSMDk6IDAwMDAwMDAwMDAwMDAwMDAKPiA+IFsgIDg2MS4x NDEyNDldIFIxMDogMDAwMDAwMDAwMDAwMDAwMCBSMTE6IDAwMDAwMDAwMDAwMDAyNDYgUjEyOiAw MDAwNTY1MzAzYTAwY2YwCj4gPiBbICA4NjEuMTQxMjQ5XSBSMTM6IDAwMDA3ZmZlOTU3NzMwZTAg UjE0OiAwMDAwMDAwMDAwMDAwMDAwIFIxNTogMDAwMDAwMDAwMDAwMDAwMAo+ID4KPiA+IFRoaXMg cGF0Y2ggbW92ZXMgdGhlIHNrYl9yZWN2X2RhdGFncmFtKCkgYmVmb3JlIGxvY2tfc29jaygpIGlu IG9yZGVyCj4gPiB0aGF0IG90aGVyIGZ1bmN0aW9ucyB0aGF0IG5lZWQgbG9ja19zb2NrIGNvdWxk IGJlIGV4ZWN1dGVkLgo+ID4KPiAKPiAKPiBXaHkgaXMgdGhpcyB0YXJnZXRpbmcgbmV0LW5leHQg dHJlZSA/Cj4gCj4gMSkgQSBmaXggc2hvdWxkIHRhcmdldCBuZXQgdHJlZQo+IDIpIEl0IHNob3Vs ZCBpbmNsdWRlIGEgRml4ZXM6IHRhZwoKVGhhbmsgeW91IGZvciB5b3VyIHRpbWUgYW5kIHN1Z2dl c3Rpb25zIQpJIHdpbGwgY2hhbmdlIHRoZSB0YXJnZXQgdHJlZSB0byBuZXQgYW5kIGFkZCBhIEZp eGVzOiB0YWcuCgo+IEFsc286Cj4gLSB0aGlzIHBhdGNoIGJ5cGFzc2VzIHRlc3RzIGluIGF4MjVf cmVjdm1zZygpCj4gLSBUaGlzIG1pZ2h0IGJyZWFrIGFwcGxpY2F0aW9ucyBkZXBlbmRpbmcgb24g YmxvY2tpbmcgcmVhZCgpIG9wZXJhdGlvbnMuCj4gCj4gSSBmZWVsIGEgcmVhbCBmaXggaXMgZ29p bmcgdG8gYmUgc2xpZ2h0bHkgbW9yZSBkaWZmaWN1bHQgdGhhbiB0aGF0LgoKSSB0aGluayBtb3Zp bmcgc2tiX3JlY3ZfZGF0YWdyYW0oKSBiZWZvcmUgbG9ja19zb2NrKCkgaXMgb2ssIGJlY2F1c2Ug aXQgZG9lcyBub3QKaG9sZCBsb2NrX3NvY2soKSBhbmQgd2lsbCBub3QgaW5mbHVlbmNlIG90aGVy IG9wZXJhdGlvbnMuIFRoZSBhcHBsaWNhdGlvbnMgd291bGQgbm90CmJyZWFrLiBXaGF0YHMgbW9y ZSwgaXQgaXMgc2FmZSB0byBtb3ZlIHNrYl9yZWN2X2RhdGFncmFtKCkgYmVmb3JlIGxvY2tfc29j aygpLgoKVGhlIGNoZWNrICJpZiAoc2stPnNrX3R5cGUgPT0gU09DS19TRVFQQUNLRVQgJiYgc2st PnNrX3N0YXRlICE9IFRDUF9FU1RBQkxJU0hFRCkiCmhhdmUgdG8gYmUgcHJvdGVjdGVkIGJ5IGxv Y2tfc29jaygpLCBiZWNhdXNlIHNrLT5za19zdGF0ZSBtYXkgYmUgY2hhbmdlZCBieQpheDI1X2Rp c2Nvbm5lY3QoKSBpbiBheDI1X2tpbGxfYnlfZGV2aWNlKCkuIAoKQmVzdCByZWdhcmRzLApEdW9t aW5nIFpob3UK