CVE-2026-64164 is a vulnerability in Linux Kernel
Published on July 19, 2026
btrfs: tracepoints: fix sleep while in atomic context in btrfs_sync_file()
In the Linux kernel, the following vulnerability has been resolved:
btrfs: tracepoints: fix sleep while in atomic context in btrfs_sync_file()
The trace event btrfs_sync_file() is called in an atomic context (all trace
events are) and its call to dput(), which is needed due to the call to
dget_parent(), can sleep, triggering a kernel splat.
This can be reproduced by enabling the trace event and running btrfs/056
from fstests for example. The splat shown in dmesg is the following:
[53.919] BUG: sleeping function called from invalid context at fs/dcache.c:970
[53.947] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 32773, name: xfs_io
[53.988] preempt_count: 2, expected: 0
[53.967] RCU nest depth: 0, expected: 0
[53.943] Preemption disabled at:
[53.944] [<0000000000000000>] 0x0
[54.078] CPU: 0 UID: 0 PID: 32773 Comm: xfs_io Tainted: G W 7.1.0-rc1-btrfs-next-232+ #1 PREEMPT(full)
[54.070] Tainted: [W]=WARN
[54.071] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[54.072] Call Trace:
[54.074] <TASK>
[54.076] dump_stack_lvl+0x56/0x80
[54.079] __might_resched.cold+0xd6/0x10f
[54.072] dput.part.0+0x24/0x110
[54.078] trace_event_raw_event_btrfs_sync_file+0x75/0x140 [btrfs]
[54.089] btrfs_sync_file+0x1ed/0x530 [btrfs]
[54.087] ? __handle_mm_fault+0x8ae/0xed0
[54.089] btrfs_do_write_iter+0x172/0x210 [btrfs]
[54.091] vfs_write+0x21f/0x450
[54.094] __x64_sys_pwrite64+0x8d/0xc0
[54.096] ? do_user_addr_fault+0x20c/0x670
[54.099] do_syscall_64+0x60/0xf20
[54.092] ? clear_bhb_loop+0x60/0xb0
[54.094] entry_SYSCALL_64_after_hwframe+0x76/0x7e
So stop using dget_parent() and dput() and access the parent dentry
directly as dentry->d_parent. This is also what ext4 is doing in
its equivalent trace event ext4_sync_file_enter().
Products Associated with CVE-2026-64164
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Affected Versions
Linux:- Version 4a7bab35fad5251c8cb738161152578cd83b6b9c and below d78b0a80eac36879ef5478707135c446920e134b is affected.
- Version 520e8b4bcf872a534a7bf61ccf880047642df296 and below 4361954f0e158af0530caa1e57f12b531be4658f is affected.
- Version e252db8ca2a01f82d472091f35d549b313278636 and below 6279992c9ba2774901c9d4dd4a481162e2534714 is affected.
- Version c09a7446aab5773f38d6abb25fce99b8e1dfbc97 and below 26b2290baaf6da6add0f782a100766e686a33f4f is affected.
- Version 32372781d664a9b03c40343e96c29d0a6139f97d and below 12a0487945c09760a5968d9333383014ea294117 is affected.
- Version 2e4adfaec97ee053ad1bdfb5036845e66f7e0d8a and below c32a7e0e3c73c1c0768556a56bd78de9f7b83780 is affected.
- Version a85b46db143fda5869e7d8df8f258ccef5fa1719 and below 0a96d9a85cd2240481297156b9bb72e10b7a8036 is affected.
- Version a85b46db143fda5869e7d8df8f258ccef5fa1719 and below c73370c677646e86fc4b1780fb07027bdf847375 is affected.
- Version d110d7cdb045715c0b45b0dfd974525bb38f653d is affected.
- Version 6.6.136 and below 6.6.142 is affected.
- Version 6.12.83 and below 6.12.92 is affected.
- Version 6.18.24 and below 6.18.34 is affected.
- Version 6.19.14 and below 6.20 is affected.
- Version 7.0 is affected.
- Before 7.0 is unaffected.
- Version 6.6.142, <= 6.6.* is unaffected.
- Version 6.12.92, <= 6.12.* is unaffected.
- Version 6.18.34, <= 6.18.* is unaffected.
- Version 7.0.11, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.