mirror of
https://github.com/torvalds/linux.git
synced 2026-03-08 02:44:41 +01:00
Linux kernel source tree
Christoph Hellwig reported a lockdep splat in generic/108: ================================ WARNING: inconsistent lock state 6.19.0+ #4827 Tainted: G N -------------------------------- inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage. swapper/1/0 [HC1[1]:SC0[0]:HE0:SE1] takes: ffff88811ed1b140 (&sb->s_type->i_lock_key#33){?.+.}-{3:3}, at: igrab+0x1a/0xb0 {HARDIRQ-ON-W} state was registered at: lock_acquire+0xca/0x2c0 _raw_spin_lock+0x2e/0x40 unlock_new_inode+0x2c/0xc0 xfs_iget+0xcf4/0x1080 xfs_trans_metafile_iget+0x3d/0x100 xfs_metafile_iget+0x2b/0x50 xfs_mount_setup_metadir+0x20/0x60 xfs_mountfs+0x457/0xa60 xfs_fs_fill_super+0x6b3/0xa90 get_tree_bdev_flags+0x13c/0x1e0 vfs_get_tree+0x27/0xe0 vfs_cmd_create+0x54/0xe0 __do_sys_fsconfig+0x309/0x620 do_syscall_64+0x8b/0xf80 entry_SYSCALL_64_after_hwframe+0x76/0x7e irq event stamp: 139080 hardirqs last enabled at (139079): [<ffffffff813a923c>] do_idle+0x1ec/0x270 hardirqs last disabled at (139080): [<ffffffff828a8d09>] common_interrupt+0x19/0xe0 softirqs last enabled at (139032): [<ffffffff8134a853>] __irq_exit_rcu+0xc3/0x120 softirqs last disabled at (139025): [<ffffffff8134a853>] __irq_exit_rcu+0xc3/0x120 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&sb->s_type->i_lock_key#33); <Interrupt> lock(&sb->s_type->i_lock_key#33); *** DEADLOCK *** 1 lock held by swapper/1/0: #0: ffff8881052c81a0 (&vblk->vqs[i].lock){-.-.}-{3:3}, at: virtblk_done+0x4b/0x110 stack backtrace: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G N 6.19.0+ #4827 PREEMPT(full) Tainted: [N]=TEST Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 Call Trace: <IRQ> dump_stack_lvl+0x5b/0x80 print_usage_bug.part.0+0x22c/0x2c0 mark_lock+0xa6f/0xe90 __lock_acquire+0x10b6/0x25e0 lock_acquire+0xca/0x2c0 _raw_spin_lock+0x2e/0x40 igrab+0x1a/0xb0 fserror_report+0x135/0x260 iomap_finish_ioend_buffered+0x170/0x210 clone_endio+0x8f/0x1c0 blk_update_request+0x1e4/0x4d0 blk_mq_end_request+0x1b/0x100 virtblk_done+0x6f/0x110 vring_interrupt+0x59/0x80 __handle_irq_event_percpu+0x8a/0x2e0 handle_irq_event+0x33/0x70 handle_edge_irq+0xdd/0x1e0 __common_interrupt+0x6f/0x180 common_interrupt+0xb7/0xe0 </IRQ> It looks like the concern here is that inode::i_lock is sometimes taken in IRQ context, and sometimes it is held when going to IRQ context, though it's a little difficult to tell since I think this is a kernel from after the actual 6.19 release but before 7.0-rc1. Either way, we don't need to take i_lock, because filesystems should not report files to fserror if they're about to be freed or have not yet been exposed to other threads, because the resulting fsnotify report will be meaningless. Therefore, bump inode::i_count directly and clarify the preconditions on the inode being passed in. Link: https://lore.kernel.org/linux-fsdevel/aY7BndIgQg3ci_6s@infradead.org/ Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Link: https://patch.msgid.link/177148129564.716249.3069780698231701540.stgit@frogsfrogsfrogs Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <brauner@kernel.org> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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