mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-16 00:51:51 -04:00
af69016dab967346f759016ca503ebc61dd048b5
Unloading the HMM test module produces the following warning:
[ 3782.224783] ------------[ cut here ]------------
[ 3782.226323] Device 'hmm_dmirror0' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.
[ 3782.230570] WARNING: drivers/base/core.c:2567 at device_release+0x185/0x210, CPU#20: rmmod/1924
[ 3782.233949] Modules linked in: test_hmm(-) nvidia_uvm(O) nvidia(O)
[ 3782.236321] CPU: 20 UID: 0 PID: 1924 Comm: rmmod Tainted: G O 7.0.0-rc1+ #374 PREEMPT(full)
[ 3782.240226] Tainted: [O]=OOT_MODULE
[ 3782.241639] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
[ 3782.246193] RIP: 0010:device_release+0x185/0x210
[ 3782.247860] Code: 00 00 fc ff df 48 8d 7b 50 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 86 00 00 00 48 8b 73 50 48 85 f6 74 11 48 8d 3d db 25 29 03 <67> 48 0f b9 3a e9 0d ff ff ff 48 b8 00 00 00 00 00 fc ff df 48 89
[ 3782.254211] RSP: 0018:ffff888126577d98 EFLAGS: 00010246
[ 3782.256054] RAX: dffffc0000000000 RBX: ffffffffc2b70310 RCX: ffffffff8fe61ba1
[ 3782.258512] RDX: 1ffffffff856e062 RSI: ffff88811341eea0 RDI: ffffffff91bbacb0
[ 3782.261041] RBP: ffff888111475000 R08: 0000000000000001 R09: fffffbfff856e069
[ 3782.263471] R10: ffffffffc2b7034b R11: 00000000ffffffff R12: 0000000000000000
[ 3782.265983] R13: dffffc0000000000 R14: ffff88811341eea0 R15: 0000000000000000
[ 3782.268443] FS: 00007fd5a3689040(0000) GS:ffff88842c8d0000(0000) knlGS:0000000000000000
[ 3782.271236] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3782.273251] CR2: 00007fd5a36d2c10 CR3: 00000001242b8000 CR4: 00000000000006f0
[ 3782.275362] Call Trace:
[ 3782.276071] <TASK>
[ 3782.276678] kobject_put+0x146/0x270
[ 3782.277731] hmm_dmirror_exit+0x7a/0x130 [test_hmm]
[ 3782.279135] __do_sys_delete_module+0x341/0x510
[ 3782.280438] ? module_flags+0x300/0x300
[ 3782.281547] do_syscall_64+0x111/0x670
[ 3782.282620] entry_SYSCALL_64_after_hwframe+0x4b/0x53
[ 3782.284091] RIP: 0033:0x7fd5a3793b37
[ 3782.285303] Code: 73 01 c3 48 8b 0d c9 82 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 99 82 0c 00 f7 d8 64 89 01 48
[ 3782.290708] RSP: 002b:00007ffd68b7dc68 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
[ 3782.292817] RAX: ffffffffffffffda RBX: 000055e3c0d1c770 RCX: 00007fd5a3793b37
[ 3782.294735] RDX: 0000000000000000 RSI: 0000000000000800 RDI: 000055e3c0d1c7d8
[ 3782.296661] RBP: 0000000000000000 R08: 1999999999999999 R09: 0000000000000000
[ 3782.298622] R10: 00007fd5a3806ac0 R11: 0000000000000206 R12: 00007ffd68b7deb0
[ 3782.300576] R13: 00007ffd68b7e781 R14: 000055e3c0d1b2a0 R15: 00007ffd68b7deb8
[ 3782.301963] </TASK>
[ 3782.302371] irq event stamp: 5019
[ 3782.302987] hardirqs last enabled at (5027): [<ffffffff8cf1f062>] __up_console_sem+0x52/0x60
[ 3782.304507] hardirqs last disabled at (5036): [<ffffffff8cf1f047>] __up_console_sem+0x37/0x60
[ 3782.306086] softirqs last enabled at (4940): [<ffffffff8cd9a4b0>] __irq_exit_rcu+0xc0/0xf0
[ 3782.307567] softirqs last disabled at (4929): [<ffffffff8cd9a4b0>] __irq_exit_rcu+0xc0/0xf0
[ 3782.309105] ---[ end trace 0000000000000000 ]---
This is because the test module doesn't have a device.release method. In
this case one probably isn't needed for correctness - the device structs
are in a static array so don't need freeing when the final reference goes
away.
However some device state is freed on exit, so to ensure this happens at
the right time and to silence the warning move the deinitialisation to a
release method and assign that as the device release callback. Whilst
here also fix a minor error handling bug where cdev_device_del() wasn't
being called if allocation failed.
Link: https://lore.kernel.org/20260331063445.3551404-4-apopple@nvidia.com
Fixes: 6a760f58c7 ("mm/hmm/test: use char dev with struct device to get device node")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: Balbir Singh <balbirs@nvidia.com>
Tested-by: Zenghui Yu (Huawei) <zenghui.yu@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: <stable@vger,kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros * AI Coding Assistant - LLMs and AI-powered development tools For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst AI Coding Assistant ------------------- CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and follow the AI coding assistants documentation before contributing to the Linux kernel: * Documentation/process/coding-assistants.rst This documentation contains essential requirements about licensing, attribution, and the Developer Certificate of Origin that all AI tools must comply with. Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst
Description
Languages
C
97%
Assembly
1%
Shell
0.6%
Rust
0.5%
Python
0.4%
Other
0.3%