### [CVE-2024-26796](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-26796)
![](https://img.shields.io/static/v1?label=Product&message=Linux&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=6.6%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=cc4c07c89aada16229084eeb93895c95b7eabaa3%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=blue)

### Description

In the Linux kernel, the following vulnerability has been resolved:drivers: perf: ctr_get_width function for legacy is not definedWith parameters CONFIG_RISCV_PMU_LEGACY=y and CONFIG_RISCV_PMU_SBI=nlinux kernel crashes when you try perf record:$ perf record ls[ 46.749286] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000[ 46.750199] Oops [#1][ 46.750342] Modules linked in:[ 46.750608] CPU: 0 PID: 107 Comm: perf-exec Not tainted 6.6.0 #2[ 46.750906] Hardware name: riscv-virtio,qemu (DT)[ 46.751184] epc : 0x0[ 46.751430] ra : arch_perf_update_userpage+0x54/0x13e[ 46.751680] epc : 0000000000000000 ra : ffffffff8072ee52 sp : ff2000000022b8f0[ 46.751958] gp : ffffffff81505988 tp : ff6000000290d400 t0 : ff2000000022b9c0[ 46.752229] t1 : 0000000000000001 t2 : 0000000000000003 s0 : ff2000000022b930[ 46.752451] s1 : ff600000028fb000 a0 : 0000000000000000 a1 : ff600000028fb000[ 46.752673] a2 : 0000000ae2751268 a3 : 00000000004fb708 a4 : 0000000000000004[ 46.752895] a5 : 0000000000000000 a6 : 000000000017ffe3 a7 : 00000000000000d2[ 46.753117] s2 : ff600000028fb000 s3 : 0000000ae2751268 s4 : 0000000000000000[ 46.753338] s5 : ffffffff8153e290 s6 : ff600000863b9000 s7 : ff60000002961078[ 46.753562] s8 : ff60000002961048 s9 : ff60000002961058 s10: 0000000000000001[ 46.753783] s11: 0000000000000018 t3 : ffffffffffffffff t4 : ffffffffffffffff[ 46.754005] t5 : ff6000000292270c t6 : ff2000000022bb30[ 46.754179] status: 0000000200000100 badaddr: 0000000000000000 cause: 000000000000000c[ 46.754653] Code: Unable to access instruction at 0xffffffffffffffec.[ 46.754939] ---[ end trace 0000000000000000 ]---[ 46.755131] note: perf-exec[107] exited with irqs disabled[ 46.755546] note: perf-exec[107] exited with preempt_count 4This happens because in the legacy case the ctr_get_width function was notdefined, but it is used in arch_perf_update_userpage.Also remove extra check in riscv_pmu_ctr_get_width_mask

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/fkie-cad/nvd-json-data-feeds