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Thu, 29 Apr 2021 06:57:01 +0000 (GMT) From: Changheun Lee To: bvanassche@acm.org Cc: axboe@kernel.dk, bgoncalv@redhat.com, hch@lst.de, jaegeuk@kernel.org, linux-block@vger.kernel.org, ming.lei@redhat.com, nanich.lee@samsung.com, yi.zhang@redhat.com Subject: Re: [PATCH v2] block: Improve limiting the bio size Date: Thu, 29 Apr 2021 15:39:01 +0900 Message-Id: <20210429063901.9593-1-nanich.lee@samsung.com> X-Mailer: git-send-email 2.29.0 In-Reply-To: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprPJsWRmVeSWpSXmKPExsWy7bCmvu7eiK4Eg7PbrSxW3+1ns9h1cT6j xbQPP5ktVq4+ymTxZP0sZou9t7QtDk1uZrK4dv8Mu8X1c9PYHDg9Ll/x9rh8ttRj06pONo/d NxvYPN7vu8rm0bdlFaPH501yAexROTYZqYkpqUUKqXnJ+SmZeem2St7B8c7xpmYGhrqGlhbm Sgp5ibmptkouPgG6bpk5QHcpKZQl5pQChQISi4uV9O1sivJLS1IVMvKLS2yVUgtScgoMDQr0 ihNzi0vz0vWS83OtDA0MjEyBKhNyMhZ+MCk4w1bx9cEu9gbGOaxdjJwcEgImEnsWrAGyuTiE BHYwSry/Oo8dwvnEKHHzbwcTSJWQwDdGib+3bbsYOcA69q81h6jZyyhx4MddqO7PjBJtjw6A NbAJ6Ej0vb3FBmKLCIhJXP7yjRGkiFlgNaNE683tYAlhARuJ5S93sYPYLAKqEod+3wZr5hWw ktjzfzkbxH3yEn/u9zCD2JwC1hJn9+xkg6gRlDg58wkLiM0MVNO8dTYzyAIJgVYOibmdz9kh ml0kjt+5zghhC0u8Or4FKi4l8fndXjaIhm5Giea2+YwQzgRGiSXPlzFBVBlLfPr8mRHkaWYB TYn1u/QhwooSO3/PZYTYzCfx7msPKyRceCU62oQgSlQkzrTcZ4bZ9XztTqiJHhJ7ri1hgQRX H6NEx8+fTBMYFWYheWgWkodmIWxewMi8ilEstaA4Nz212LDAFDmKNzGCU6qW5Q7G6W8/6B1i ZOJgPMQowcGsJML7e11nghBvSmJlVWpRfnxRaU5q8SFGU2BwT2SWEk3OByb1vJJ4Q1MjY2Nj CxMzczNTYyVx3nTn6gQhgfTEktTs1NSC1CKYPiYOTqkGJp4p/r2/1VVd/ktU1z+PNT9m/1TP 0f3j0+SdOyd/Evt51sjgx37uzRbbXuRtjVj5uaIlorXk4TkbjrKD9ySrBPYee/LsrBfbJGeH n9cNWrp+Bot9PqXx82zlnL3th/aWPwxddvX15bjenKVT2bxclp3fPWWawYq66Iapifd2FH6Z cDtRcsKDB0srN27ovN32xDfkjOP1sLcXfpnGTupsOfLdInOmjK/B0gkFfvb8Uyyy69OmxWfn OXVumRCwm9NurX96UuQi6fJvSz+zp7AVlRtMcer42mdwoG7BU6Hp1xnyuSQW5ycdvlGlURtj sGv3wbgp4XtO2PDM5g589Me6W+7etIzlk79sYb0cHnIrjkmJpTgj0VCLuag4EQB8V0R7MgQA AA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrKLMWRmVeSWpSXmKPExsWy7bCSnO7eiK4Eg3/bpCxW3+1ns9h1cT6j xbQPP5ktVq4+ymTxZP0sZou9t7QtDk1uZrK4dv8Mu8X1c9PYHDg9Ll/x9rh8ttRj06pONo/d NxvYPN7vu8rm0bdlFaPH501yAexRXDYpqTmZZalF+nYJXBkLP5gUnGGr+PpgF3sD4xzWLkYO DgkBE4n9a827GLk4hAR2M0pMe/2GuYuREyguJXH8xFuoGmGJw4eLIWo+MkocP3uIDaSGTUBH ou/tLTBbREBM4vKXb4wgRcwCWxkl3v5bygiSEBawkVj+chc7iM0ioCpx6PdtJhCbV8BKYs// 5WwQy+Ql/tzvAVvMKWAtcXbPTjaQxUJANT/P+EOUC0qcnPmEBcRmBipv3jqbeQKjwCwkqVlI UgsYmVYxSqYWFOem5xYbFhjmpZbrFSfmFpfmpesl5+duYgSHvJbmDsbtqz7oHWJk4mA8xCjB wawkwvt7XWeCEG9KYmVValF+fFFpTmrxIUZpDhYlcd4LXSfjhQTSE0tSs1NTC1KLYLJMHJxS DUy20V+nvbtx0r5q2ZeYEHbVXo7Qa+/Tp/Fs5FtpWHO+6OunGJ2VRt+LGxc7/PWTtXBWU02J yQpkDk0PnflIfM2D6Y7CZhWPjbSKeizjYhYmx7f+rp778Oj15J+Op4yYNZTN1tyNTV5wZmuD QxSHz2xOk8Vaxi++3Nq1d2bgrB87L18+Pf1inb30au+b3z7N3aeo9q7ulnBN56/p2YdKe7YL yq6d1XBr8+ObjtsDm822yVoc9D5/d9WPLdNCDP67f0gp+nk5dfOC0Mkx14ROWe9PnXWGi0Nv S8HprYKWa0zj1NvClKsenMg0fcKzdNdRvetlZwLc7BpTF14+d2PVxcdPaz8eTT+7q/jRqdPG 3GFcSizFGYmGWsxFxYkAMAQBkugCAAA= X-CMS-MailID: 20210429065701epcas1p363667a6f0c598f27bb5afde32473ea39 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: SVC_REQ_APPROVE CMS-TYPE: 101P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20210429065701epcas1p363667a6f0c598f27bb5afde32473ea39 References: Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org > On 4/28/21 12:21 AM, Changheun Lee wrote: > > Actually I don't know why NULL pointer dereference is occurred with Bart's > > patch in blk_rq_map_kern(). And same problem have not occured yet in my > > test environment with Bart's patch. > > Maybe I missed something, or missunderstood? > > The call trace that I shared on the linux-block mailing list was > encountered inside a VM that has a SATA disk attached to it and also a > SATA CD-ROM. Does replicating that setup allow to reproduce the NULL > pointer dereference that I reported? > > Bart. I can reproduce and see NULL pointer dereference in same call path without your patch. But I can't reproduced it with your patch. I tested in ubuntu via grub. SATA disk is attached only in my environment. Actually I didn't test in VM yet. I'll try. Thanks, Changheun.