CVE-2026-31423

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net/sched: sch_hfsc: fix divide-by-zero in rtsc_min()<br /> <br /> m2sm() converts a u32 slope to a u64 scaled value. For large inputs<br /> (e.g. m1=4000000000), the result can reach 2^32. rtsc_min() stores<br /> the difference of two such u64 values in a u32 variable `dsm` and<br /> uses it as a divisor. When the difference is exactly 2^32 the<br /> truncation yields zero, causing a divide-by-zero oops in the<br /> concave-curve intersection path:<br /> <br /> Oops: divide error: 0000<br /> RIP: 0010:rtsc_min (net/sched/sch_hfsc.c:601)<br /> Call Trace:<br /> init_ed (net/sched/sch_hfsc.c:629)<br /> hfsc_enqueue (net/sched/sch_hfsc.c:1569)<br /> [...]<br /> <br /> Widen `dsm` to u64 and replace do_div() with div64_u64() so the full<br /> difference is preserved.