CVE-2024-49935
NoneCVSS
—
EPSS
0.2%
Published
Oct 21, 2024
CISA due date
—
Cloudanix analysis
A bug in Linux power-management code can cause the whole computer to crash when certain hardware power-saving features are used.
- Exploitation
- Local Privilege
- Attacker needs
- Low Privilege
- Complexity
- Moderate
- Impact
- Denial Of Service
- Component
- OS kernel
- Class
- Memory Corruption
- Remediation
- Patch
- Effort
- Medium
- Patch risk
- Low
What it actually does
Invalid CPU index value of 0xffffffff passed to cpumask_clear_cpu() inside exit_round_robin() in the acpi_pad driver causes clear_bit() to compute an out-of-bounds address, resulting in a kernel paging fault and crash.
Why it matters to the business
Unexpected kernel crashes on Linux systems that load the acpi_pad module can cause unplanned downtime, service interruption, and require manual recovery or reboot.
How an attack unfolds
An attacker with the ability to influence ACPI PAD power-saving thread scheduling (for example via repeated CPU hotplug or power-management events) can cause tsk_in_cpu[tsk_index] to remain -1 when exit_round_robin() runs; the subsequent unconditional cpumask_clear_cpu() then dereferences an invalid address and panics the kernel. No remote code execution is involved; the flaw produces denial-of-service via crash.
How to fix it
Upgrade the Linux kernel to a revision containing commit 82191a21a0dedc8c64e14f07f5d568d09bc4b331 or later; rebuild and reboot with the patched kernel. Where package managers provide it, install the fixed mariadb-connector-c package version 3.1.11-2.el8_3 or newer if that component is present.
How to confirm the fix worked
Verify the running kernel contains commit 82191a21a0dedc8c64e14f07f5d568d09bc4b331 (uname -r or /proc/version_signature); reproduce ACPI PAD load/unload cycles under CPU hotplug stress and confirm absence of the paging fault at ffffffffe0740618 or equivalent.
Typical attack path
- Trigger conditions that activate the acpi_pad power_saving_thread
- Leave tsk_in_cpu entry at 0xffffffff instead of a valid CPU number
- Invoke exit_round_robin() which calls cpumask_clear_cpu(-1)
- clear_bit() performs misaligned memory access leading to page fault
- Kernel oops/panic terminates the system
How to detect it
Search kernel logs and kdump vmcores for the strings power_saving_thread, exit_round_robin, pad_busy_cpus_bits, and the RIP address corresponding to clear_bit on an all-ones index; correlate with acpi_pad module load events and CPU mask operations that contain 0xffffffff.
- power_saving_thread+0x313
- pad_busy_cpus_bits
- tsk_in_cpu
- ffffffffc0726923
- acpi_pad/.*Kdump
- BUG: unable to handle kernel paging request at ffffffffe0740618
What your security team should do
- Apply the fixed kernel commit or updated package within the next maintenance window
- Monitor kernel logs for acpi_pad oops signatures until all systems are patched
- Disable the acpi_pad module via modprobe.blacklist if the workload permits and risk tolerance requires immediate mitigation
The record
In the Linux kernel, the following vulnerability has been resolved: ACPI: PAD: fix crash in exit_round_robin() The kernel occasionally crashes in cpumask_clear_cpu(), which is called within exit_round_robin(), because when executing clear_bit(nr, addr) with nr set to 0xffffffff, the address calculation may cause misalignment within the memory, leading to access to an invalid memory address. ---------- BUG: unable to handle kernel paging request at ffffffffe0740618 ... CPU: 3 PID: 2919323 Comm: acpi_pad/14 Kdump: loaded Tainted: G OE X --------- - - 4.18.0-425.19.2.el8_7.x86_64 #1 ... RIP: 0010:power_saving_thread+0x313/0x411 [acpi_pad] Code: 89 cd 48 89 d3 eb d1 48 c7 c7 55 70 72 c0 e8 64 86 b0 e4 c6 05 0d a1 02 00 01 e9 bc fd ff ff 45 89 e4 42 8b 04 a5 20 82 72 c0 <f0> 48 0f b3 05 f4 9c 01 00 42 c7 04 a5 20 82 72 c0 ff ff ff ff 31 RSP: 0018:ff72a5d51fa77ec8 EFLAGS: 00010202 RAX: 00000000ffffffff RBX: ff462981e5d8cb80 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246 RBP: ff46297556959d80 R08: 0000000000000382 R09: ff46297c8d0f38d8 R10: 0000000000000000 R11: 0000000000000001 R12: 000000000000000e R13: 0000000000000000 R14: ffffffffffffffff R15: 000000000000000e FS: 0000000000000000(0000) GS:ff46297a800c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffe0740618 CR3: 0000007e20410004 CR4: 0000000000771ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? acpi_pad_add+0x120/0x120 [acpi_pad] kthread+0x10b/0x130 ? set_kthread_struct+0x50/0x50 ret_from_fork+0x1f/0x40 ... CR2: ffffffffe0740618 crash> dis -lr ffffffffc0726923 ... /usr/src/debug/kernel-4.18.0-425.19.2.el8_7/linux-4.18.0-425.19.2.el8_7.x86_64/./include/linux/cpumask.h: 114 0xffffffffc0726918 <power_saving_thread+776>: mov %r12d,%r12d /usr/src/debug/kernel-4.18.0-425.19.2.el8_7/linux-4.18.0-425.19.2.el8_7.x86_64/./include/linux/cpumask.h: 325 0xffffffffc072691b <power_saving_thread+779>: mov -0x3f8d7de0(,%r12,4),%eax /usr/src/debug/kernel-4.18.0-425.19.2.el8_7/linux-4.18.0-425.19.2.el8_7.x86_64/./arch/x86/include/asm/bitops.h: 80 0xffffffffc0726923 <power_saving_thread+787>: lock btr %rax,0x19cf4(%rip) # 0xffffffffc0740620 <pad_busy_cpus_bits> crash> px tsk_in_cpu[14] $66 = 0xffffffff crash> px 0xffffffffc072692c+0x19cf4 $99 = 0xffffffffc0740620 crash> sym 0xffffffffc0740620 ffffffffc0740620 (b) pad_busy_cpus_bits [acpi_pad] crash> px pad_busy_cpus_bits[0] $42 = 0xfffc0 ---------- To fix this, ensure that tsk_in_cpu[tsk_index] != -1 before calling cpumask_clear_cpu() in exit_round_robin(), just as it is done in round_robin_cpu(). [ rjw: Subject edit, avoid updates to the same value ]
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Debian:11 | linux | 0 | No fix |
| Debian:11 | linux-6.1 | 0 | 6.1.119-1~deb11u1 |
| Debian:12 | linux | 0 | No fix |
| Debian:13 | linux | 0 | No fix |
| Debian:13 | linux | 0 | 6.11.4-1 |
| Linux | Kernel | 0 | 5.4.296 |
| Linux | Kernel | 2.6.32 | 5.4.296 |
| Mageia:9 | kernel | 0 | 6.6.58-2.mga9 |
| Mageia:9 | kernel-firmware | 0 | 20240909-1.mga9 |
| Mageia:9 | kernel-firmware-nonfree | 0 | 20240909-1.mga9.nonfree |
| Mageia:9 | kernel-linus | 0 | 6.6.58-2.mga9 |
| Mageia:9 | kmod-virtualbox | 0 | 7.0.20-57.mga9 |
| Mageia:9 | kmod-xtables-addons | 0 | 3.24-65.mga9 |
| Mageia:9 | radeon-firmware | 0 | 20240909-1.mga9.nonfree |
| SUSE:Linux Enterprise High Availability Extension 15 SP5 | kernel-default | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise High Availability Extension 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Live Patching 12 SP5 | kernel-default | 0 | 4.12.14-122.255.1 |
| SUSE:Linux Enterprise Live Patching 12 SP5 | kgraft-patch-SLE12-SP5_Update_67 | 0 | 1-8.5.1 |
| SUSE:Linux Enterprise Live Patching 15 SP5 | kernel-default | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Live Patching 15 SP5 | kernel-livepatch-SLE15-SP5-RT_Update_23 | 0 | 1-150500.11.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP5 | kernel-livepatch-SLE15-SP5_Update_21 | 0 | 1-150500.11.5.1 |
| SUSE:Linux Enterprise Live Patching 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6-RT_Update_5 | 0 | 1-150600.1.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6_Update_6 | 0 | 1-150600.13.3.5 |
| SUSE:Linux Enterprise Micro 5.5 | kernel-default | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Micro 5.5 | kernel-default-base | 0 | 5.14.21-150500.55.88.1.150500.6.39.4 |
| SUSE:Linux Enterprise Micro 5.5 | kernel-rt | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Linux Enterprise Micro 5.5 | kernel-source-rt | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP5 | kernel-64kb | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP5 | kernel-default | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP5 | kernel-default-base | 0 | 5.14.21-150500.55.88.1.150500.6.39.4 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP5 | kernel-source | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP5 | kernel-zfcpdump | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-64kb | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-default-base | 0 | 6.4.0-150600.23.30.1.150600.12.12.6 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-source | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-zfcpdump | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-coco | 0 | 6.4.0-15061.9.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-coco_debug | 0 | 6.4.0-15061.9.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-source-coco | 0 | 6.4.0-15061.9.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-syms-coco | 0 | 6.4.0-15061.9.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP5 | kernel-docs | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP5 | kernel-obs-build | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP5 | kernel-source | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP5 | kernel-syms | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-docs | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-obs-build | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-source | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-syms | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Legacy 15 SP5 | kernel-default | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Legacy 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP5 | kernel-azure | 0 | 5.14.21-150500.33.75.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP5 | kernel-source-azure | 0 | 5.14.21-150500.33.75.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP5 | kernel-syms-azure | 0 | 5.14.21-150500.33.75.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP6 | kernel-azure | 0 | 6.4.0-150600.8.17.2 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP6 | kernel-source-azure | 0 | 6.4.0-150600.8.17.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP6 | kernel-syms-azure | 0 | 6.4.0-150600.8.17.1 |
| SUSE:Linux Enterprise Server 12 SP5-LTSS | kernel-default | 0 | 4.12.14-122.255.1 |
| SUSE:Linux Enterprise Server 12 SP5-LTSS | kernel-source | 0 | 4.12.14-122.255.1 |
| SUSE:Linux Enterprise Server 12 SP5-LTSS | kernel-syms | 0 | 4.12.14-122.255.1 |
| SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 | kernel-default | 0 | 4.12.14-122.255.1 |
| SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 | kernel-source | 0 | 4.12.14-122.255.1 |
| SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 | kernel-syms | 0 | 4.12.14-122.255.1 |
| SUSE:Linux Enterprise Workstation Extension 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Real Time Module 15 SP5 | kernel-rt | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Real Time Module 15 SP5 | kernel-rt_debug | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Real Time Module 15 SP5 | kernel-source-rt | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Real Time Module 15 SP5 | kernel-syms-rt | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Real Time Module 15 SP6 | kernel-rt | 0 | 6.4.0-150600.10.17.1 |
| SUSE:Real Time Module 15 SP6 | kernel-rt_debug | 0 | 6.4.0-150600.10.17.1 |
| SUSE:Real Time Module 15 SP6 | kernel-source-rt | 0 | 6.4.0-150600.10.17.1 |
| SUSE:Real Time Module 15 SP6 | kernel-syms-rt | 0 | 6.4.0-150600.10.17.1 |
| Ubuntu:20.04:LTS | linux-aws-5.15 | 0 | 5.15.0-1073.79~20.04.1 |
| Ubuntu:20.04:LTS | linux-azure-5.15 | 0 | 5.15.0-1078.87~20.04.1 |
| Ubuntu:20.04:LTS | linux-gcp-5.15 | 0 | 5.15.0-1072.80~20.04.1 |
| Ubuntu:20.04:LTS | linux-hwe-5.15 | 0 | 5.15.0-127.137~20.04.1 |
| Ubuntu:20.04:LTS | linux-ibm-5.15 | 0 | 5.15.0-1066.69~20.04.1 |
| Ubuntu:20.04:LTS | linux-intel-iotg-5.15 | 0 | 5.15.0-1071.77~20.04.1 |
| Ubuntu:20.04:LTS | linux-lowlatency-hwe-5.15 | 0 | 5.15.0-127.137~20.04.1 |
| Ubuntu:20.04:LTS | linux-oracle-5.15 | 0 | 5.15.0-1071.77~20.04.1 |
| Ubuntu:22.04:LTS | linux | 0 | 5.15.0-127.137 |
| Ubuntu:22.04:LTS | linux-aws | 0 | 5.15.0-1073.79 |
| Ubuntu:22.04:LTS | linux-azure | 0 | 5.15.0-1078.87 |
| Ubuntu:22.04:LTS | linux-gcp | 0 | 5.15.0-1072.80 |
| Ubuntu:22.04:LTS | linux-gke | 0 | 5.15.0-1070.76 |
| Ubuntu:22.04:LTS | linux-gkeop | 0 | 5.15.0-1056.63 |
| Ubuntu:22.04:LTS | linux-ibm | 0 | 5.15.0-1066.69 |
| Ubuntu:22.04:LTS | linux-intel-iotg | 0 | 5.15.0-1071.77 |
| Ubuntu:22.04:LTS | linux-kvm | 0 | 5.15.0-1070.75 |
| Ubuntu:22.04:LTS | linux-lowlatency | 0 | 5.15.0-127.137 |
| Ubuntu:22.04:LTS | linux-nvidia | 0 | 5.15.0-1068.69 |
| Ubuntu:22.04:LTS | linux-oracle | 0 | 5.15.0-1071.77 |
| Ubuntu:22.04:LTS | linux-raspi | 0 | 5.15.0-1066.69 |
| Ubuntu:22.04:LTS | linux-xilinx-zynqmp | 0 | 5.15.0-1039.43 |
| Ubuntu:24.10 | linux | 0 | 6.11.0-18.18 |
| Ubuntu:24.10 | linux-aws | 0 | 6.11.0-1009.10 |
| Ubuntu:24.10 | linux-azure | 0 | 6.11.0-1009.9 |
| Ubuntu:24.10 | linux-gcp | 0 | 6.11.0-1009.9 |
| Ubuntu:24.10 | linux-lowlatency | 0 | 6.11.0-1010.11 |
| Ubuntu:24.10 | linux-oracle | 0 | 6.11.0-1011.12 |
| Ubuntu:24.10 | linux-raspi | 0 | 6.11.0-1008.8 |
| Ubuntu:24.10 | linux-realtime | 0 | 6.11.0-1005.5 |
| openSUSE:Leap 15.5 | kernel-azure | 0 | 5.14.21-150500.33.75.1 |
| openSUSE:Leap 15.5 | kernel-rt | 0 | 5.14.21-150500.13.79.1 |
| openSUSE:Leap 15.5 | kernel-rt_debug | 0 | 5.14.21-150500.13.79.1 |
| openSUSE:Leap 15.5 | kernel-source-azure | 0 | 5.14.21-150500.33.75.1 |
| openSUSE:Leap 15.5 | kernel-source-rt | 0 | 5.14.21-150500.13.79.1 |
| openSUSE:Leap 15.5 | kernel-syms-azure | 0 | 5.14.21-150500.33.75.1 |
| openSUSE:Leap 15.5 | kernel-syms-rt | 0 | 5.14.21-150500.13.79.1 |
| openSUSE:Leap 15.6 | dtb-aarch64 | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-64kb | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-azure | 0 | 6.4.0-150600.8.17.2 |
| openSUSE:Leap 15.6 | kernel-debug | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-default-base | 0 | 6.4.0-150600.23.30.1.150600.12.12.6 |
| openSUSE:Leap 15.6 | kernel-docs | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-kvmsmall | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-obs-build | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-obs-qa | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-rt | 0 | 6.4.0-150600.10.17.1 |
| openSUSE:Leap 15.6 | kernel-rt_debug | 0 | 6.4.0-150600.10.17.1 |
| openSUSE:Leap 15.6 | kernel-source | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-source-azure | 0 | 6.4.0-150600.8.17.1 |
| openSUSE:Leap 15.6 | kernel-source-rt | 0 | 6.4.0-150600.10.17.1 |
| openSUSE:Leap 15.6 | kernel-syms | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-syms-azure | 0 | 6.4.0-150600.8.17.1 |
| openSUSE:Leap 15.6 | kernel-syms-rt | 0 | 6.4.0-150600.10.17.1 |
| openSUSE:Leap 15.6 | kernel-zfcpdump | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap Micro 5.5 | kernel-rt | 0 | 5.14.21-150500.13.79.1 |
| openSUSE:Tumbleweed | kernel-source | 0 | 6.11.8-1.1 |
| openSUSE:Tumbleweed | kernel-source-longterm | 0 | 6.12.11-1.1 |
Related vulnerabilities
- CVE-2025-39885 In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix recursive… Also affects linux
- CVE-2025-39883 In the Linux kernel, the following vulnerability has been resolved: mm/memory-failure… Also affects linux
- CVE-2025-39876 In the Linux kernel, the following vulnerability has been resolved: net: fec: Fix… Also affects linux
- CVE-2025-39869 In the Linux kernel, the following vulnerability has been resolved: dmaengine: ti: edma… Also affects linux
- CVE-2025-39873 In the Linux kernel, the following vulnerability has been resolved: can: xilinx_can… Also affects linux
- CVE-2025-39863 In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: fix… Also affects linux
- CVE-2025-39865 In the Linux kernel, the following vulnerability has been resolved: tee: fix NULL pointer… Also affects linux
- CVE-2025-39866 In the Linux kernel, the following vulnerability has been resolved: fs: writeback: fix… Also affects linux