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smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com; spf=pass smtp.mailfrom=sk.com; arc=none smtp.client-ip=166.125.252.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sk.com X-AuditID: a67dfc5b-c45ff70000001609-14-68de3419f97f From: Byungchul Park To: linux-kernel@vger.kernel.org Cc: kernel_team@skhynix.com, torvalds@linux-foundation.org, damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, will@kernel.org, tglx@linutronix.de, rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org, tytso@mit.edu, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, gregkh@linuxfoundation.org, kernel-team@lge.com, linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@kernel.org, minchan@kernel.org, hannes@cmpxchg.org, vdavydov.dev@gmail.com, sj@kernel.org, jglisse@redhat.com, dennis@kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, vbabka@suse.cz, ngupta@vflare.org, linux-block@vger.kernel.org, josef@toxicpanda.com, linux-fsdevel@vger.kernel.org, jack@suse.cz, jlayton@kernel.org, dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org, dri-devel@lists.freedesktop.org, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com, harry.yoo@oracle.com, chris.p.wilson@intel.com, gwan-gyeong.mun@intel.com, max.byungchul.park@gmail.com, boqun.feng@gmail.com, longman@redhat.com, yunseong.kim@ericsson.com, ysk@kzalloc.com, yeoreum.yun@arm.com, netdev@vger.kernel.org, matthew.brost@intel.com, her0gyugyu@gmail.com, corbet@lwn.net, catalin.marinas@arm.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, sumit.semwal@linaro.org, gustavo@padovan.org, christian.koenig@amd.com, andi.shyti@kernel.org, arnd@arndb.de, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, rppt@kernel.org, surenb@google.com, mcgrof@kernel.org, petr.pavlu@suse.com, da.gomez@kernel.org, samitolvanen@google.com, paulmck@kernel.org, frederic@kernel.org, neeraj.upadhyay@kernel.org, joelagnelf@nvidia.com, josh@joshtriplett.org, urezki@gmail.com, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang@linux.dev, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, chuck.lever@oracle.com, neil@brown.name, okorniev@redhat.com, Dai.Ngo@oracle.com, tom@talpey.com, trondmy@kernel.org, anna@kernel.org, kees@kernel.org, bigeasy@linutronix.de, clrkwllms@kernel.org, mark.rutland@arm.com, ada.coupriediaz@arm.com, kristina.martsenko@arm.com, wangkefeng.wang@huawei.com, broonie@kernel.org, kevin.brodsky@arm.com, dwmw@amazon.co.uk, shakeel.butt@linux.dev, ast@kernel.org, ziy@nvidia.com, yuzhao@google.com, baolin.wang@linux.alibaba.com, usamaarif642@gmail.com, joel.granados@kernel.org, richard.weiyang@gmail.com, geert+renesas@glider.be, tim.c.chen@linux.intel.com, linux@treblig.org, alexander.shishkin@linux.intel.com, lillian@star-ark.net, chenhuacai@kernel.org, francesco@valla.it, guoweikang.kernel@gmail.com, link@vivo.com, jpoimboe@kernel.org, masahiroy@kernel.org, brauner@kernel.org, thomas.weissschuh@linutronix.de, oleg@redhat.com, mjguzik@gmail.com, andrii@kernel.org, wangfushuai@baidu.com, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-i2c@vger.kernel.org, linux-arch@vger.kernel.org, linux-modules@vger.kernel.org, rcu@vger.kernel.org, linux-nfs@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: [PATCH v17 46/47] SUNRPC: relocate struct rcu_head to the first field of struct rpc_xprt Date: Thu, 2 Oct 2025 17:12:46 +0900 Message-Id: <20251002081247.51255-47-byungchul@sk.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20251002081247.51255-1-byungchul@sk.com> References: <20251002081247.51255-1-byungchul@sk.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Brightmail-Tracker: H4sIAAAAAAAAA02Sa2yLYRTH8zx9b2uUV228LjHKiGE2GTkuESSy9wsRvggRa9Y3WttKOnYR krELFpfp1OjWpbOlqXZsOkZR2c1lNtLZMMk2OjVbqEptYhfmrUX4cvLLec7/d54Ph5HI3eQM RqM9KOi0yiQFJSWkvgmlS6fHdqujyx/GgPu6HUGOc4yAn/pHNIy5HiEweLwU+C2nEfRVnUDQ 5p0I7YN+CnytxRgumhwEON/dpaH10yiG5vwrGAr7KSgqzMJi6cNguHYPw5DFRoMlMwKKnrWR 0GM10tB1zkBAU/crEj716il4+ziXhNuZ72gYaPdgKM0tJ6DtbjEF3RVjJLhrm0ko+NKLwDLo p6H3ZS6GqmzR8qzoOQkfjSYMDYOfMRS8MFPQc9ZHQ8D0iwR7KwGG0ZMUHPv2FoFpIAYG7Dbx cw+76fXRvK26BvMVJRWIHxnWIz4nXySnsYvmzY5DfHajj+SrrZF82f1+zJcGBkneYTtF8Y6A nuZLR/okfJ6vHfNPLo0QvNOzauusndK1KiFJkyrolq2Ll6pbrm444Jqcnq3fnYn8sjwUwnBs LOc/cYP+yw/sX3GQKXYh19ExJAlyKDuHqz7TSwZZwjbP4l61LgnyFFbJfWvoEmcYhmAjuMCP HcG2jF3JWbMukePKcM5eVftHEyL22zzNRJDl7Aoux5+Nx+cnc02XvURQIxHXVpbIxzeFc1m3 isSoVNQ0hHDfbzvxuHM6V2ftIPIRa/wvbvwXN/4XNyOJDck12tRkpSYpNkqdodWkRyXsT3Yg 8c4sR0d33UEB9/Z6xDJIMUHmjuhSy0llakpGcj3iGIkiVBZv7VTLZSplxmFBt3+P7lCSkFKP ZjKEYpps+fc0lZzdqzwoJArCAUH39xUzITMykdQVpzC8T+zcfNOsPRU5KeFFwvz4xWlTmri5 jAoKSm6UNb6ucq/tW90479zMRXu9plC2Qmo2Fnc2hLXUbNpiOB6l+vC0M22VI+aNIvGCEDdM nX2+ZuxMXr93wLlvwdDG4cojcVSEf9QVDd6wOyWVU8MLz9fYthX3z65rKvO47uUqiBS1MiZS oktR/ganEuEEYwMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA02Sa0hTYRjHec9d6cRxGZ3Ksgaj6GIXsh4qulDhIejyrQgqVx7amDe2spQC bY6krGwxV1upKQ3bTE0rMlkMJSt11LQb6dLlskJtYpp5XWdJ1JeX3/s8P/7P8+FhcNkIOYdR Jx8XtcnKRDkVToTv3qBfPnvNR9VKZ/kMeJvlImBoMIeAGxVlFORUXSfhVbkDQcdQDoLhMSsO hpogARPGBhoGR9poCDobEOR7jDiU3c/C4EflJAU99QMITD4/BeZvWQQEbLkILN1WGr49jYO+ jloSgt4vGLz72YvA5p/EwO86h2AiXwOFxdUUjLlf4mA2vUJwy+fF4Wul1Lzf8BGBs/QsBZ/z HuDQ6p8Or4cCFLwwXaCgz3MDg++VFBSddZJw02pEoC+poCD/ZhUBNZ2PafD0jGPQnm/EwFG1 Czps3QQ05RVj0n6SdW8WWM16THq+YmC6W4vBiM1OQ3NJOwG2TAVY3a0kfCq10DDuWwXBohRo cHyhwXvZREB530tyiwkJw4ZLhGCvfogJhpYJSigrKEPC2KgRCYO39bhgyJO+9b0BXMiuPinc buqlhNGhN5Tg/FlECI3FvHDFvVyosXhpIfvJB3rv+gPhGxPERHWaqF2xKT5c1Xxna6oz4lS2 8WAmCrDnURjDc2v4J45+LMQUt4h//34ED3Ekt4CvvthNhhjnmqL4t55lIZ7BKfkf9V7JYRiC U/ADv/aHyiy3li/VXyOnIqN5R6XrT0yYVG/1NREhlnGxvCGQjU35EfyL634iFINLYysKZFOT onn9Ayueh1jLf5bln2X5zypCuB1FqpPTkpTqxNgYnUaVnqw+FXM0JakKSQdpOzN+5REabI2r QxyD5NNYj8KrkpHKNF16Uh3iGVweycaXtqtkbIIyPUPUphzWnkgUdXVoLkPIZ7E794nxMu6Y 8rioEcVUUfu3izFhczLRh8aWPRBVeFCh3fbZ3bgO254rX9072XNu4Xx3f+PchKhJfdy8q5u2 bC5xm8/bYtpcW2MWz+zqYjtrT7ZohI0F9tPajOd7I7b7Tmc034L2nK5n9wotbOehpbFO89Xh w/1ZrsVc3xFFbYV5x1qHnW8zTUtN0oRFu9riBsbujAZzV8gJnUq5agmu1Sl/A2JfrD6MAwAA X-CFilter-Loop: Reflected While compiling Linux kernel with DEPT on, the following error was observed: ./include/linux/rcupdate.h:1084:17: note: in expansion of macro =E2=80=98BUILD_BUG_ON=E2=80=99 1084 | BUILD_BUG_ON(offsetof(typeof(*(ptr)), rhf) >=3D 4096); \ | ^~~~~~~~~~~~ ./include/linux/rcupdate.h:1047:29: note: in expansion of macro 'kvfree_rcu_arg_2' 1047 | #define kfree_rcu(ptr, rhf) kvfree_rcu_arg_2(ptr, rhf) | ^~~~~~~~~~~~~~~~ net/sunrpc/xprt.c:1856:9: note: in expansion of macro 'kfree_rcu' 1856 | kfree_rcu(xprt, rcu); | ^~~~~~~~~ CC net/kcm/kcmproc.o make[4]: *** [scripts/Makefile.build:203: net/sunrpc/xprt.o] Error 1 Since kfree_rcu() assumes 'offset of struct rcu_head in a rcu-managed struct < 4096', the offest of struct rcu_head in struct rpc_xprt should not exceed 4096 but does, due to the debug information added by DEPT. Relocate struct rcu_head to the first field of struct rpc_xprt from an arbitrary location to avoid the issue and meet the assumption. Reported-by: Yunseong Kim Signed-off-by: Byungchul Park --- include/linux/sunrpc/xprt.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index f46d1fb8f71a..666e42a17a31 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -211,6 +211,14 @@ enum xprt_transports { =20 struct rpc_sysfs_xprt; struct rpc_xprt { + /* + * Place struct rcu_head within the first 4096 bytes of struct + * rpc_xprt if sizeof(struct rpc_xprt) > 4096, so that + * kfree_rcu() can simply work assuming that. See the comment + * in kfree_rcu(). + */ + struct rcu_head rcu; + struct kref kref; /* Reference count */ const struct rpc_xprt_ops *ops; /* transport methods */ unsigned int id; /* transport id */ @@ -317,7 +325,6 @@ struct rpc_xprt { #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) struct dentry *debugfs; /* debugfs directory */ #endif - struct rcu_head rcu; const struct xprt_class *xprt_class; struct rpc_sysfs_xprt *xprt_sysfs; bool main; /*mark if this is the 1st transport */ --=20 2.17.1