In the Linux kernel, the following vulnerability has been resolved:

ring-buffer: Fix deadloop issue on reading trace_pipe

Soft lockup occurs when reading file 'trace_pipe':

watchdog: BUG: soft lockup - CPU#6 stuck for 22s! [cat:4488]
[...]
RIP: 0010:ring_buffer_empty_cpu+0xed/0x170
RSP: 0018:ffff88810dd6fc48 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000246 RCX: ffffffff93d1aaeb
RDX: ffff88810a280040 RSI: 0000000000000008 RDI: ffff88811164b218
RBP: ffff88811164b218 R08: 0000000000000000 R09: ffff88815156600f
R10: ffffed102a2acc01 R11: 0000000000000001 R12: 0000000051651901
R13: 0000000000000000 R14: ffff888115e49500 R15: 0000000000000000
[...]
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8d853c2000 CR3: 000000010dcd8000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__find_next_entry+0x1a8/0x4b0
? peek_next_entry+0x250/0x250
? down_write+0xa5/0x120
? down_write_killable+0x130/0x130
trace_find_next_entry_inc+0x3b/0x1d0
tracing_read_pipe+0x423/0xae0
? tracing_splice_read_pipe+0xcb0/0xcb0
vfs_read+0x16b/0x490
ksys_read+0x105/0x210
? __ia32_sys_pwrite64+0x200/0x200
? switch_fpu_return+0x108/0x220
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x61/0xc6

Through the vmcore, I found it's because in tracing_read_pipe(),
ring_buffer_empty_cpu() found some buffer is not empty but then it
cannot read anything due to "rb_num_of_entries() == 0" always true,
Then it infinitely loop the procedure due to user buffer not been
filled, see following code path:

tracing_read_pipe() {
... ...
waitagain:
tracing_wait_pipe() // 1. find non-empty buffer here
trace_find_next_entry_inc() // 2. loop here try to find an entry
__find_next_entry()
ring_buffer_empty_cpu(); // 3. find non-empty buffer
peek_next_entry() // 4. but peek always return NULL
ring_buffer_peek()
rb_buffer_peek()
rb_get_reader_page()
// 5. because rb_num_of_entries() == 0 always true here
// then return NULL
// 6. user buffer not been filled so goto 'waitgain'
// and eventually leads to an deadloop in kernel!!!
}

By some analyzing, I found that when resetting ringbuffer, the 'entries'
of its pages are not all cleared (see rb_reset_cpu()). Then when reducing
the ringbuffer, and if some reduced pages exist dirty 'entries' data, they
will be added into 'cpu_buffer->overrun' (see rb_remove_pages()), which
cause wrong 'overrun' count and eventually cause the deadloop issue.

To fix it, we need to clear every pages in rb_reset_cpu().

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00036.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Linux Linux unaffected
Version Status Constraints
a5fb833172eca69136e9ee1ada778e404086ab8a affected < 0a29dae5786d263016a9aceb1e56bf3fd4cc6fa0
a5fb833172eca69136e9ee1ada778e404086ab8a affected < a55e8a3596048c2f7b574049aeb1885b5abba1cc
a5fb833172eca69136e9ee1ada778e404086ab8a affected < e84829522fc72bb43556b31575731de0440ac0dd
a5fb833172eca69136e9ee1ada778e404086ab8a affected < 5e68f1f3a20fe9b6bde018e353269fbfa289609c
a5fb833172eca69136e9ee1ada778e404086ab8a affected < bb14a93bccc92766b1d9302c6bcbea17d4bce306
a5fb833172eca69136e9ee1ada778e404086ab8a affected < 8b0b63fdac6b70a45614e7d4b30e5bbb93deb007
a5fb833172eca69136e9ee1ada778e404086ab8a affected < 27bdd93e44cc28dd9b94893fae146b83d4f5b31e
a5fb833172eca69136e9ee1ada778e404086ab8a affected < 7e42907f3a7b4ce3a2d1757f6d78336984daf8f5
Linux Linux affected
Version Status Constraints
3.6 affected —
0 unaffected < 3.6
4.14.322 unaffected ≤ 4.14.*
4.19.291 unaffected ≤ 4.19.*
5.4.251 unaffected ≤ 5.4.*
5.10.188 unaffected ≤ 5.10.*
5.15.121 unaffected ≤ 5.15.*
6.1.40 unaffected ≤ 6.1.*
6.4.5 unaffected ≤ 6.4.*
6.5 unaffected ≤ *

Configuration 1 [-]

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.5:rc1:*:*:*:*:*:*

No data.

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Fixes

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References
Link Providers
https://git.kernel.org/stable/c/0a29dae5786d263016a9aceb1e56bf3fd4cc6fa0 cve-icon cve-icon
https://git.kernel.org/stable/c/27bdd93e44cc28dd9b94893fae146b83d4f5b31e cve-icon cve-icon
https://git.kernel.org/stable/c/5e68f1f3a20fe9b6bde018e353269fbfa289609c cve-icon cve-icon
https://git.kernel.org/stable/c/7e42907f3a7b4ce3a2d1757f6d78336984daf8f5 cve-icon cve-icon
https://git.kernel.org/stable/c/8b0b63fdac6b70a45614e7d4b30e5bbb93deb007 cve-icon cve-icon
https://git.kernel.org/stable/c/a55e8a3596048c2f7b574049aeb1885b5abba1cc cve-icon cve-icon
https://git.kernel.org/stable/c/bb14a93bccc92766b1d9302c6bcbea17d4bce306 cve-icon cve-icon
https://git.kernel.org/stable/c/e84829522fc72bb43556b31575731de0440ac0dd cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025100705-CVE-2023-53668-b06b@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2023-53668 cve-icon
https://www.cve.org/CVERecord?id=CVE-2023-53668 cve-icon
History

Tue, 03 Feb 2026 19:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-125
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.5:rc1:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

 cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'}

Wed, 08 Oct 2025 13:45:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Wed, 08 Oct 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate

Tue, 07 Oct 2025 15:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix deadloop issue on reading trace_pipe Soft lockup occurs when reading file 'trace_pipe': watchdog: BUG: soft lockup - CPU#6 stuck for 22s! [cat:4488] [...] RIP: 0010:ring_buffer_empty_cpu+0xed/0x170 RSP: 0018:ffff88810dd6fc48 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000246 RCX: ffffffff93d1aaeb RDX: ffff88810a280040 RSI: 0000000000000008 RDI: ffff88811164b218 RBP: ffff88811164b218 R08: 0000000000000000 R09: ffff88815156600f R10: ffffed102a2acc01 R11: 0000000000000001 R12: 0000000051651901 R13: 0000000000000000 R14: ffff888115e49500 R15: 0000000000000000 [...] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8d853c2000 CR3: 000000010dcd8000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __find_next_entry+0x1a8/0x4b0 ? peek_next_entry+0x250/0x250 ? down_write+0xa5/0x120 ? down_write_killable+0x130/0x130 trace_find_next_entry_inc+0x3b/0x1d0 tracing_read_pipe+0x423/0xae0 ? tracing_splice_read_pipe+0xcb0/0xcb0 vfs_read+0x16b/0x490 ksys_read+0x105/0x210 ? __ia32_sys_pwrite64+0x200/0x200 ? switch_fpu_return+0x108/0x220 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x61/0xc6 Through the vmcore, I found it's because in tracing_read_pipe(), ring_buffer_empty_cpu() found some buffer is not empty but then it cannot read anything due to "rb_num_of_entries() == 0" always true, Then it infinitely loop the procedure due to user buffer not been filled, see following code path: tracing_read_pipe() { ... ... waitagain: tracing_wait_pipe() // 1. find non-empty buffer here trace_find_next_entry_inc() // 2. loop here try to find an entry __find_next_entry() ring_buffer_empty_cpu(); // 3. find non-empty buffer peek_next_entry() // 4. but peek always return NULL ring_buffer_peek() rb_buffer_peek() rb_get_reader_page() // 5. because rb_num_of_entries() == 0 always true here // then return NULL // 6. user buffer not been filled so goto 'waitgain' // and eventually leads to an deadloop in kernel!!! } By some analyzing, I found that when resetting ringbuffer, the 'entries' of its pages are not all cleared (see rb_reset_cpu()). Then when reducing the ringbuffer, and if some reduced pages exist dirty 'entries' data, they will be added into 'cpu_buffer->overrun' (see rb_remove_pages()), which cause wrong 'overrun' count and eventually cause the deadloop issue. To fix it, we need to clear every pages in rb_reset_cpu().
Title ring-buffer: Fix deadloop issue on reading trace_pipe
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-10-07T15:21:26.164Z

Reserved: 2025-10-07T15:16:59.663Z

Link: CVE-2023-53668

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2025-10-07T16:15:50.640

Modified: 2026-02-03T19:10:39.770

Link: CVE-2023-53668

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-10-07T00:00:00Z

Links: CVE-2023-53668 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-10-08T13:35:35Z

Weaknesses