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

block, bfq: Fix division by zero error on zero wsum

When the weighted sum is zero the calculation of limit causes
a division by zero error. Fix this by continuing to the next level.

This was discovered by running as root:

stress-ng --ioprio 0

Fixes divison by error oops:

[ 521.450556] divide error: 0000 [#1] SMP NOPTI
[ 521.450766] CPU: 2 PID: 2684464 Comm: stress-ng-iopri Not tainted 6.2.1-1280.native #1
[ 521.451117] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.1-0-g3208b098f51a-prebuilt.qemu.org 04/01/2014
[ 521.451627] RIP: 0010:bfqq_request_over_limit+0x207/0x400
[ 521.451875] Code: 01 48 8d 0c c8 74 0b 48 8b 82 98 00 00 00 48 8d 0c c8 8b 85 34 ff ff ff 48 89 ca 41 0f af 41 50 48 d1 ea 48 98 48 01 d0 31 d2 <48> f7 f1 41 39 41 48 89 85 34 ff ff ff 0f 8c 7b 01 00 00 49 8b 44
[ 521.452699] RSP: 0018:ffffb1af84eb3948 EFLAGS: 00010046
[ 521.452938] RAX: 000000000000003c RBX: 0000000000000000 RCX: 0000000000000000
[ 521.453262] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffb1af84eb3978
[ 521.453584] RBP: ffffb1af84eb3a30 R08: 0000000000000001 R09: ffff8f88ab8a4ba0
[ 521.453905] R10: 0000000000000000 R11: 0000000000000001 R12: ffff8f88ab8a4b18
[ 521.454224] R13: ffff8f8699093000 R14: 0000000000000001 R15: ffffb1af84eb3970
[ 521.454549] FS: 00005640b6b0b580(0000) GS:ffff8f88b3880000(0000) knlGS:0000000000000000
[ 521.454912] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 521.455170] CR2: 00007ffcbcae4e38 CR3: 00000002e46de001 CR4: 0000000000770ee0
[ 521.455491] PKRU: 55555554
[ 521.455619] Call Trace:
[ 521.455736] <TASK>
[ 521.455837] ? bfq_request_merge+0x3a/0xc0
[ 521.456027] ? elv_merge+0x115/0x140
[ 521.456191] bfq_limit_depth+0xc8/0x240
[ 521.456366] __blk_mq_alloc_requests+0x21a/0x2c0
[ 521.456577] blk_mq_submit_bio+0x23c/0x6c0
[ 521.456766] __submit_bio+0xb8/0x140
[ 521.457236] submit_bio_noacct_nocheck+0x212/0x300
[ 521.457748] submit_bio_noacct+0x1a6/0x580
[ 521.458220] submit_bio+0x43/0x80
[ 521.458660] ext4_io_submit+0x23/0x80
[ 521.459116] ext4_do_writepages+0x40a/0xd00
[ 521.459596] ext4_writepages+0x65/0x100
[ 521.460050] do_writepages+0xb7/0x1c0
[ 521.460492] __filemap_fdatawrite_range+0xa6/0x100
[ 521.460979] file_write_and_wait_range+0xbf/0x140
[ 521.461452] ext4_sync_file+0x105/0x340
[ 521.461882] __x64_sys_fsync+0x67/0x100
[ 521.462305] ? syscall_exit_to_user_mode+0x2c/0x1c0
[ 521.462768] do_syscall_64+0x3b/0xc0
[ 521.463165] entry_SYSCALL_64_after_hwframe+0x5a/0xc4
[ 521.463621] RIP: 0033:0x5640b6c56590
[ 521.464006] Code: 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 80 3d 71 70 0e 00 00 74 17 b8 4a 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

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 0.00025.

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
76f1df88bbc2f984eb0418cc90de0a8384e63604 affected
< 1655cfc85250a224b0d9486c8136baeea33b9b5c
76f1df88bbc2f984eb0418cc90de0a8384e63604 affected
< c0346a59d719461248c6dc6f21c9e55ef836b66f
76f1df88bbc2f984eb0418cc90de0a8384e63604 affected
< e53413f8deedf738a6782cc14cc00bd5852ccf18
Linux Linux affected
Version Status Constraints
5.17 affected
—
0 unaffected
< 5.17
6.1.30 unaffected
≤ 6.1.*
6.3.4 unaffected
≤ 6.3.*
6.4 unaffected
≤ *

No data.

No data.

No data.

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Advisories

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Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://git.kernel.org/stable/c/1655cfc85250a224b0d9486c8136baeea33b9b5c cve-icon cve-icon
https://git.kernel.org/stable/c/c0346a59d719461248c6dc6f21c9e55ef836b66f cve-icon cve-icon
https://git.kernel.org/stable/c/e53413f8deedf738a6782cc14cc00bd5852ccf18 cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025123034-CVE-2023-54242-9771@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2023-54242 cve-icon
https://www.cve.org/CVERecord?id=CVE-2023-54242 cve-icon
History

Wed, 31 Dec 2025 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low

Tue, 30 Dec 2025 12:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: block, bfq: Fix division by zero error on zero wsum When the weighted sum is zero the calculation of limit causes a division by zero error. Fix this by continuing to the next level. This was discovered by running as root: stress-ng --ioprio 0 Fixes divison by error oops: [ 521.450556] divide error: 0000 [#1] SMP NOPTI [ 521.450766] CPU: 2 PID: 2684464 Comm: stress-ng-iopri Not tainted 6.2.1-1280.native #1 [ 521.451117] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.1-0-g3208b098f51a-prebuilt.qemu.org 04/01/2014 [ 521.451627] RIP: 0010:bfqq_request_over_limit+0x207/0x400 [ 521.451875] Code: 01 48 8d 0c c8 74 0b 48 8b 82 98 00 00 00 48 8d 0c c8 8b 85 34 ff ff ff 48 89 ca 41 0f af 41 50 48 d1 ea 48 98 48 01 d0 31 d2 <48> f7 f1 41 39 41 48 89 85 34 ff ff ff 0f 8c 7b 01 00 00 49 8b 44 [ 521.452699] RSP: 0018:ffffb1af84eb3948 EFLAGS: 00010046 [ 521.452938] RAX: 000000000000003c RBX: 0000000000000000 RCX: 0000000000000000 [ 521.453262] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffb1af84eb3978 [ 521.453584] RBP: ffffb1af84eb3a30 R08: 0000000000000001 R09: ffff8f88ab8a4ba0 [ 521.453905] R10: 0000000000000000 R11: 0000000000000001 R12: ffff8f88ab8a4b18 [ 521.454224] R13: ffff8f8699093000 R14: 0000000000000001 R15: ffffb1af84eb3970 [ 521.454549] FS: 00005640b6b0b580(0000) GS:ffff8f88b3880000(0000) knlGS:0000000000000000 [ 521.454912] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 521.455170] CR2: 00007ffcbcae4e38 CR3: 00000002e46de001 CR4: 0000000000770ee0 [ 521.455491] PKRU: 55555554 [ 521.455619] Call Trace: [ 521.455736] <TASK> [ 521.455837] ? bfq_request_merge+0x3a/0xc0 [ 521.456027] ? elv_merge+0x115/0x140 [ 521.456191] bfq_limit_depth+0xc8/0x240 [ 521.456366] __blk_mq_alloc_requests+0x21a/0x2c0 [ 521.456577] blk_mq_submit_bio+0x23c/0x6c0 [ 521.456766] __submit_bio+0xb8/0x140 [ 521.457236] submit_bio_noacct_nocheck+0x212/0x300 [ 521.457748] submit_bio_noacct+0x1a6/0x580 [ 521.458220] submit_bio+0x43/0x80 [ 521.458660] ext4_io_submit+0x23/0x80 [ 521.459116] ext4_do_writepages+0x40a/0xd00 [ 521.459596] ext4_writepages+0x65/0x100 [ 521.460050] do_writepages+0xb7/0x1c0 [ 521.460492] __filemap_fdatawrite_range+0xa6/0x100 [ 521.460979] file_write_and_wait_range+0xbf/0x140 [ 521.461452] ext4_sync_file+0x105/0x340 [ 521.461882] __x64_sys_fsync+0x67/0x100 [ 521.462305] ? syscall_exit_to_user_mode+0x2c/0x1c0 [ 521.462768] do_syscall_64+0x3b/0xc0 [ 521.463165] entry_SYSCALL_64_after_hwframe+0x5a/0xc4 [ 521.463621] RIP: 0033:0x5640b6c56590 [ 521.464006] Code: 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 80 3d 71 70 0e 00 00 74 17 b8 4a 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c
Title block, bfq: Fix division by zero error on zero wsum
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-01-05T11:36:58.701Z

Reserved: 2025-12-30T12:06:44.510Z

Link: CVE-2023-54242

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-12-30T13:16:12.770

Modified: 2025-12-31T20:42:43.210

Link: CVE-2023-54242

cve-icon Redhat

Severity : Low

Publid Date: 2025-12-30T00:00:00Z

Links: CVE-2023-54242 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.