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Thu, 10 Aug 2023 15:37:31 +0900 (KST) Received: from green245 (unknown [107.99.41.245]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20230810063730epsmtip181e590b0d0b8aa13b59d1d1fcaec1cd9~58jZ-RdTT2499824998epsmtip11; Thu, 10 Aug 2023 06:37:30 +0000 (GMT) Date: Thu, 10 Aug 2023 12:04:11 +0530 From: Kanchan Joshi To: Ming Lei Cc: Christoph Hellwig , Keith Busch , linux-nvme@lists.infradead.org, Sagi Grimberg , Guangwu Zhang , Anuj Gupta Subject: Re: [PATCH] nvme: core: don't hold rcu read lock in nvme_ns_chr_uring_cmd_iopoll Message-ID: <20230810063411.GA13970@green245> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprMJsWRmVeSWpSXmKPExsWy7bCmpu6a1ispBm/3C1s0TfjLbLHkym4W i5WrjzJZTDp0jdFi/rKn7BaHJjczWax7/Z7Fgd3j/L2NLB6bVnWyeWxeUu+x+2YDm8f7fVfZ PPq2rGIMYIvKtslITUxJLVJIzUvOT8nMS7dV8g6Od443NTMw1DW0tDBXUshLzE21VXLxCdB1 y8wBukVJoSwxpxQoFJBYXKykb2dTlF9akqqQkV9cYquUWpCSU2BSoFecmFtcmpeul5daYmVo YGBkClSYkJ0xacE01oL33BXNL/rZGhg/cXYxcnBICJhInPmQ18XIxSEksJtRoufZGlYI5xOj xO55X5ngnHndM4EynGAdK/83s0MkdjJKXPm0HMp5xiixf90bdpAqFgFViUWftrOD7GAT0JS4 MLkUJCwioCRx9+5qsHpmgYuMEtM/rQObKiwQLbH9/SIWEJtXQFei8+M/JghbUOLkzCcsIHM4 BdQklq2XBgmLCihLHNh2HOw6CYFGDolTH9czQ1znInF+SzfUpcISr45vYYewpSRe9rdB2ckS l2aeY4KwSyQe7zkIZdtLtJ7qB5vDLJAhsfXqQnYIm0+i9/cTJkh48Up0tAlBlCtK3Jv0FGqV uMTDGUugbA+JyffaoWFymlHi68ozrBMY5WYheWcWkhUQtpVE54cm1llAK5gFpCWW/+OAMDUl 1u/SX8DIuopRMrWgODc9tdi0wCgvtRwex8n5uZsYwalTy2sH48MHH/QOMTJxMB5ilOBgVhLh tQ2+lCLEm5JYWZValB9fVJqTWnyI0RQYPROZpUST84HJO68k3tDE0sDEzMzMxNLYzFBJnPd1 69wUIYH0xJLU7NTUgtQimD4mDk6pBqY412Q3hkquayfYt/1gOlJ1xcy1em/+h1s6Rt9WTNR0 uruR7W3uVP5F8cpT8j2+m2gauykaPepdX+GumlbAseOghXjWZPb87gkChbHX/so2P2ZcuOm0 rur+WcXXs1MPpHW1Mh9Xtd3zab79avHb9Sv4nBZxrJao2GDP83iGneH6D7VHn6z9tlqy+NGs 8lfS0zK2v9F75aNXVq75oWvyR9fUUn7N2/9P3xYrltzk8v5S4aGQo78+/3Ez/fLO/ushry8x EjyTcjTnG/DvEbu77cHJXbWVD//E7t2gdKRw16kp7ivY4q85X248Wu3Vo3Pnbsrzl9eZai61 /Pk0eXO/caL6slVveb9tdT4k6Pzw+TJdJZbijERDLeai4kQA5yayWyYEAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrLLMWRmVeSWpSXmKPExsWy7bCSnO6a1ispBvMtLZom/GW2WHJlN4vF ytVHmSwmHbrGaDF/2VN2i0OTm5ks1r1+z+LA7nH+3kYWj02rOtk8Ni+p99h9s4HN4/2+q2we fVtWMQawRXHZpKTmZJalFunbJXBl7P2wlb1gIWfFkam/mBsY97F3MXJySAiYSKz83wxkc3EI CWxnlFjY+xUqIS7RfO0HlC0ssfLfc6iiJ4wSrc+2MoIkWARUJRZ92g6U4OBgE9CUuDC5FCQs IqAkcffuarB6ZoHLjBIzb+xlBUkIC0RLbH+/iAXE5hXQlej8+I8JYuhZRokXE14zQyQEJU7O fAJWxCxgJjFv80NmkAXMAtISy/9xgJicAmoSy9ZLg1SICihLHNh2nGkCo+AsJM2zkDTPQmhe wMi8ilE0taA4Nz03ucBQrzgxt7g0L10vOT93EyM4BrSCdjAuW/9X7xAjEwfjIUYJDmYlEV7b 4EspQrwpiZVVqUX58UWlOanFhxilOViUxHmVczpThATSE0tSs1NTC1KLYLJMHJxSDUw96XcT 6s9dtQ1uTueNvBHD/iZD7/+Xw/LWzOmx7ZcuPgmtmzzjvebFw2yrAzzdVIVUQibfXMx+u7pT ebnfGuNJLLuOZSec+cf1WD5SymDXzTUrZ8r+Yn6lIb7cXGfLzJrly/eJbjx4c4rt5Fl+CsVW T1YlBb769GRODafyqr2n7c5mrNHSjZ4y9eJJ3leqrLHafyMLJq158Tj747kTc/esCFp7+I7W 0b1y6S1v5U/nbli4+EyVV5jdss9LZ+sWn2pLNC6d6ecq0Zh4QYzR4aZK+z1m9s35HrsvHAmV /yd076uB7I4NS05fuLDvyZFI8X+XilbvfhM5w3bxsdKqw8vXn3nANIfz/Oo1D4J3THv4NFKJ pTgj0VCLuag4EQCz8MGO8AIAAA== X-CMS-MailID: 20230810063732epcas5p326808a29ec3e75dfc6c8f1262f1b1740 X-Msg-Generator: CA Content-Type: multipart/mixed; boundary="----nvFln8z3L_krFSQI_duuyTsYVGNcxCMU6qftyQwhOSKtHzaF=_43047_" CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20230809020844epcas5p30e520491fa59ab8c20836d4275931e8f References: <20230809020440.174682-1-ming.lei@redhat.com> <20230809065920.GA19415@green245> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230809_233742_987455_0AB8F765 X-CRM114-Status: GOOD ( 17.91 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org ------nvFln8z3L_krFSQI_duuyTsYVGNcxCMU6qftyQwhOSKtHzaF=_43047_ Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Disposition: inline On Wed, Aug 09, 2023 at 03:53:35PM +0800, Ming Lei wrote: >On Wed, Aug 09, 2023 at 12:29:20PM +0530, Kanchan Joshi wrote: >> On Wed, Aug 09, 2023 at 10:04:40AM +0800, Ming Lei wrote: >> > Now nvme_ns_chr_uring_cmd_iopoll() has switched to request based io >> > polling, and the associated NS is guaranteed to be live in case of >> > io polling, so request is guaranteed to be valid because blk-mq uses >> > pre-allocated request pool. >> > >> > Remove the rcu read lock in nvme_ns_chr_uring_cmd_iopoll(), which >> > isn't needed any more after switching to request based io polling. >> >> > Fix "BUG: sleeping function called from invalid context" because >> > set_page_dirty_lock() from blk_rq_unmap_user() may sleep. >> > >> > Fixes: 585079b6e425 ("nvme: wire up async polling for io passthrough commands") >> > Reported-by: Guangwu Zhang >> >> Thanks Ming. Looks fine, but any link to this report? >> I don't see this breaking in my tests. So I wonder how to reproduce and >> improve the coverage. > >It is reported in RH BZ2227639, and follows the stack trace: Tried to access, but no luck. Any chance that steps can be posted here? ------nvFln8z3L_krFSQI_duuyTsYVGNcxCMU6qftyQwhOSKtHzaF=_43047_ Content-Type: text/plain; charset="utf-8" ------nvFln8z3L_krFSQI_duuyTsYVGNcxCMU6qftyQwhOSKtHzaF=_43047_--