Linux kernel source tree
Go to file
Filipe Manana 532085d00e btrfs: fix deadlock cloning inline extent when using flushoncommit
In commit b48c980b6a ("btrfs: fix deadlock between reflink and
transaction commit when using flushoncommit") a deadlock was fixed
between reflinks and transaction commits when the fs is mounted with the
flushoncommit option. This happened when we had to copy an inline extent's
data to the destination file. However the issue was fixed only for the
case where the destination offset is 0, it missed the case when the offset
is greater than zero.

Fix this by ensuring we get i_size update whenever we copied an inline
extent's data into the destination file.

Syzbot reported this with the following trace:

   INFO: task kworker/u8:3:57 blocked for more than 143 seconds.
         Not tainted syzkaller #0
   "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
   task:kworker/u8:3    state:D stack:21600 pid:57    tgid:57    ppid:2      task_flags:0x4208160 flags:0x00080000
   Workqueue: writeback wb_workfn (flush-btrfs-129)
   Call Trace:
    <TASK>
    context_switch kernel/sched/core.c:5402 [inline]
    __schedule+0x16f9/0x5500 kernel/sched/core.c:7204
    __schedule_loop kernel/sched/core.c:7283 [inline]
    schedule+0x164/0x360 kernel/sched/core.c:7298
    wait_extent_bit fs/btrfs/extent-io-tree.c:905 [inline]
    btrfs_lock_extent_bits+0x59c/0x700 fs/btrfs/extent-io-tree.c:2008
    btrfs_lock_extent fs/btrfs/extent-io-tree.h:152 [inline]
    btrfs_invalidate_folio+0x440/0xc00 fs/btrfs/inode.c:7718
    extent_writepage fs/btrfs/extent_io.c:1848 [inline]
    extent_write_cache_pages fs/btrfs/extent_io.c:2552 [inline]
    btrfs_writepages+0x12f3/0x2410 fs/btrfs/extent_io.c:2684
    do_writepages+0x32e/0x550 mm/page-writeback.c:2571
    __writeback_single_inode+0x133/0x10e0 fs/fs-writeback.c:1764
    writeback_sb_inodes+0x97f/0x1980 fs/fs-writeback.c:2056
    wb_writeback+0x445/0xb00 fs/fs-writeback.c:2241
    wb_do_writeback fs/fs-writeback.c:2388 [inline]
    wb_workfn+0x3fd/0xf20 fs/fs-writeback.c:2428
    process_one_work+0x98b/0x1630 kernel/workqueue.c:3318
    process_scheduled_works kernel/workqueue.c:3401 [inline]
    worker_thread+0xb49/0x1140 kernel/workqueue.c:3482
    kthread+0x388/0x470 kernel/kthread.c:436
    ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
    ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
    </TASK>
   INFO: task syz.0.145:8523 blocked for more than 143 seconds.
         Not tainted syzkaller #0
   "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
   task:syz.0.145       state:D stack:22752 pid:8523  tgid:8522  ppid:5850   task_flags:0x400140 flags:0x00080002
   Call Trace:
    <TASK>
    context_switch kernel/sched/core.c:5402 [inline]
    __schedule+0x16f9/0x5500 kernel/sched/core.c:7204
    __schedule_loop kernel/sched/core.c:7283 [inline]
    schedule+0x164/0x360 kernel/sched/core.c:7298
    wb_wait_for_completion+0x3e8/0x790 fs/fs-writeback.c:227
    __writeback_inodes_sb_nr+0x24c/0x2d0 fs/fs-writeback.c:2847
    try_to_writeback_inodes_sb+0x9a/0xc0 fs/fs-writeback.c:2895
    btrfs_start_delalloc_flush fs/btrfs/transaction.c:2182 [inline]
    btrfs_commit_transaction+0x813/0x2fc0 fs/btrfs/transaction.c:2371
    btrfs_sync_file+0xdf4/0x1230 fs/btrfs/file.c:1822
    generic_write_sync include/linux/fs.h:2663 [inline]
    btrfs_do_write_iter+0x6a9/0x840 fs/btrfs/file.c:1473
    new_sync_write fs/read_write.c:595 [inline]
    vfs_write+0x629/0xba0 fs/read_write.c:688
    ksys_write+0x156/0x270 fs/read_write.c:740
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f
   RIP: 0033:0x7f5a0bdece59
   RSP: 002b:00007f5a0b446028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
   RAX: ffffffffffffffda RBX: 00007f5a0c065fa0 RCX: 00007f5a0bdece59
   RDX: 000000000000029f RSI: 0000200000000200 RDI: 0000000000000004
   RBP: 00007f5a0be82d6f R08: 0000000000000000 R09: 0000000000000000
   R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
   R13: 00007f5a0c066038 R14: 00007f5a0c065fa0 R15: 00007ffe149206b8
    </TASK>
   INFO: task syz.0.145:8539 blocked for more than 143 seconds.
         Not tainted syzkaller #0
   "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
   task:syz.0.145       state:D stack:23704 pid:8539  tgid:8522  ppid:5850   task_flags:0x400140 flags:0x00080002
   Call Trace:
    <TASK>
    context_switch kernel/sched/core.c:5402 [inline]
    __schedule+0x16f9/0x5500 kernel/sched/core.c:7204
    __schedule_loop kernel/sched/core.c:7283 [inline]
    schedule+0x164/0x360 kernel/sched/core.c:7298
    wait_current_trans+0x39f/0x590 fs/btrfs/transaction.c:536
    start_transaction+0xbd8/0x1820 fs/btrfs/transaction.c:716
    clone_copy_inline_extent fs/btrfs/reflink.c:299 [inline]
    btrfs_clone+0x1316/0x2540 fs/btrfs/reflink.c:574
    btrfs_clone_files+0x271/0x3f0 fs/btrfs/reflink.c:795
    btrfs_remap_file_range+0x76b/0x1320 fs/btrfs/reflink.c:948
    vfs_clone_file_range+0x435/0x7b0 fs/remap_range.c:403
    ioctl_file_clone fs/ioctl.c:239 [inline]
    ioctl_file_clone_range fs/ioctl.c:257 [inline]
    do_vfs_ioctl+0xe15/0x1540 fs/ioctl.c:544
    __do_sys_ioctl fs/ioctl.c:595 [inline]
    __se_sys_ioctl+0x82/0x170 fs/ioctl.c:583
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f
   RIP: 0033:0x7f5a0bdece59
   RSP: 002b:00007f5a0b425028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
   RAX: ffffffffffffffda RBX: 00007f5a0c066090 RCX: 00007f5a0bdece59
   RDX: 00002000000000c0 RSI: 000000004020940d RDI: 0000000000000004
   RBP: 00007f5a0be82d6f R08: 0000000000000000 R09: 0000000000000000
   R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
   R13: 00007f5a0c066128 R14: 00007f5a0c066090 R15: 00007ffe149206b8
    </TASK>

Reported-by: syzbot+c7443384724bb0f9e913@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/6a150a09.820a0220.e7972.0006.GAE@google.com/
Fixes: 05a5a7621c ("Btrfs: implement full reflink support for inline extents")
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-06-09 18:22:45 +02:00
arch Miscellaneous x86 fixes: 2026-06-07 13:12:29 -07:00
block block-7.1-20260529 2026-05-29 10:41:07 -07:00
certs Clang build fixes for 7.1 2026-04-24 09:29:51 -07:00
crypto crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks 2026-05-20 16:36:45 -07:00
Documentation Including fixes from Netfilter, wireless and Bluetooth. 2026-06-04 14:35:55 -07:00
drivers regulator: Fix for v7.1 2026-06-07 12:39:36 -07:00
fs btrfs: fix deadlock cloning inline extent when using flushoncommit 2026-06-09 18:22:45 +02:00
include btrfs: zoned: decode 'RECLAIM_ZONES' state in tracepoints 2026-06-09 11:49:26 +01:00
init memblock: updates for 7.0-rc1 2026-04-18 11:29:14 -07:00
io_uring io_uring-7.1-20260605 2026-06-05 13:52:15 -07:00
ipc ipc: limit next_id allocation to the valid ID range 2026-05-21 19:06:11 -07:00
kernel Miscellaneous timer fixes: 2026-06-07 13:02:02 -07:00
lib vdso/datastore: Mark vdso_k_*_data pointers as __ro_after_init 2026-06-02 21:39:29 +02:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
mm 13 hotfixes. All are for MM. 10 are cc:stable and the remaining 3 2026-06-02 08:59:35 -07:00
net udp: clear skb->dev before running a sockmap verdict 2026-06-04 09:01:51 -07:00
rust rust: helpers: add is_vmalloc_addr wrapper for NOMMU builds 2026-05-27 20:01:04 +02:00
samples soc: drivers for 7.1 2026-04-16 20:34:34 -07:00
scripts Rust fixes for v7.1 (2nd) 2026-06-06 09:44:42 -07:00
security security/keys: fix missed RCU read section on lookup 2026-05-28 11:45:41 -07:00
sound ALSA: seq: dummy: fix UMP event stack overread 2026-06-05 10:08:57 +02:00
tools vfs-7.1-rc7.fixes 2026-06-06 07:28:59 -07:00
usr kbuild: uapi: also test UAPI headers against C++ compilers 2026-03-25 13:24:42 +01:00
virt KVM: Don't WARN if memory is dirtied without a vCPU when the VM is dying 2026-06-03 16:43:55 +02:00
.clang-format Devicetree updates for v7.0: 2026-02-11 18:27:08 -08:00
.clippy.toml rust: bump Clippy's MSRV and clean incompatible_msrv allows 2026-04-07 09:51:39 +02:00
.cocciconfig
.editorconfig editorconfig: add rst extension 2026-01-26 19:07:09 -08:00
.get_maintainer.ignore .get_maintainer.ignore: add myself 2026-04-02 16:48:25 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rust: provide an option to inline C helpers into Rust 2026-03-30 02:03:52 +02:00
.mailmap 13 hotfixes. 9 are for MM. 9 are cc:stable and the remaining 4 address 2026-05-26 08:23:19 -07:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS Delete some obsolete networking code 2026-04-24 09:41:58 -07:00
Kbuild checksyscalls: move instance functionality into generic code 2026-04-05 09:21:32 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS cgroup: Fixes for v7.1-rc6 2026-06-03 08:59:24 -07:00
Makefile Linux 7.1-rc7 2026-06-07 15:37:58 -07:00
README docs: add AI Coding Assistants documentation 2026-01-06 14:55:06 -07:00

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