CVE-2026-93182sched/fair: Fix overflow in update_tg_cfs_runnable()
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In the Linux kernel, the following vulnerability has been resolved: sched/fair: Fix overflow in update_tg_cfs_runnable() A divide-by-zero crash is observed when running hackbench: [14697.488452] CPU: 112 UID: 0 PID: 124791 Comm: hackbench Not tainted 7.1.0-rc2+ [14697.492627] RIP: 0010:propagate_entity_load_avg+0x35f/0x3e0 [14697.506799] <TASK> [14697.507411] __dequeue_task+0x2b4/0xc70 [14697.508677] dequeue_task_fair+0x36/0x370 [14697.509047] dequeue_task+0x101/0x2f0 [14697.509426] __schedule+0x1b1/0x1a00 [14697.510868] anon_pipe_read+0x3da/0x450 [14697.511400] vfs_read+0x361/0x390 [14697.512053] __x64_sys_read+0x19/0x30 The divide-by-zero happens here: if (scale_load_down(gcfs_rq->load.weight)) { load_sum = div_u64(gcfs_rq->avg.load_sum, scale_load_down(gcfs_rq->load.weight)); } gcfs_rq->load.weight is an insane large value and is truncated to the lower 32 bits by div_u64, which happen to be 0. Using AI for investigation, the cause is a u32 overflow in update_tg_cfs_runnable(), and flat pickup became a victim when using tg_tasks(): u32 new_sum, divider; ... new_sum = se->avg.runnable_avg * divider; <-- boom The following sequence shows how this triggers the crash: propagate_entity_load_avg() update_tg_cfs_runnable() # u32 overflow corrupts runnable_sum __update_load_avg_cfs_rq() ___update_load_avg() # computes insane runnable_avg update_tg_load_avg() # propagates to tg->runnable_avg update_cfs_group() calc_concur_shares() tg_tasks() # long-to-int truncation, negative nr reweight_entity() # corrupted se->load.weight update_load_add() # corrupted cfs_rq->load.weight propagate_entity_load_avg() update_tg_cfs_load() div_u64() # divide-by-zero Fix by widening new_sum from u32 to u64 (no need to force tg_tasks() to return unsigned long after this fix)
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 19, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 builds before 39d707097a0820c6e87eff4195f0940e8ff1147e; 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 builds before 69fafae4eb2c9fc9bcff1bcbfcccf5d197434d75; 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 builds before 7cc237e3bc1733928313d2462b413ae441b0eef3; 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 builds before 18fdd0978ec3dda0ff6865cd273e47e022180710; from 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 before f94e62d21faad5e244d0874598a4d0ebbc0ea405; 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 builds before 4f166adb5cb0525d9e32d45729fd8f28c80acbee | CNA record |
References
- https://git.kernel.org/stable/c/39d707097a0820c6e87eff4195f0940e8ff1147e
- https://git.kernel.org/stable/c/69fafae4eb2c9fc9bcff1bcbfcccf5d197434d75
- https://git.kernel.org/stable/c/7cc237e3bc1733928313d2462b413ae441b0eef3
- https://git.kernel.org/stable/c/18fdd0978ec3dda0ff6865cd273e47e022180710
- https://git.kernel.org/stable/c/f94e62d21faad5e244d0874598a4d0ebbc0ea405
- https://git.kernel.org/stable/c/4f166adb5cb0525d9e32d45729fd8f28c80acbee
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.