CVE-2024-56613: sched/numa: fix memory leak due to the overwritten vma->numab_state

First published: Fri Dec 27 2024(Updated: )

In the Linux kernel, the following vulnerability has been resolved: sched/numa: fix memory leak due to the overwritten vma->numab_state [Problem Description] When running the hackbench program of LTP, the following memory leak is reported by kmemleak. # /opt/ltp/testcases/bin/hackbench 20 thread 1000 Running with 20*40 (== 800) tasks. # dmesg | grep kmemleak ... kmemleak: 480 new suspected memory leaks (see /sys/kernel/debug/kmemleak) kmemleak: 665 new suspected memory leaks (see /sys/kernel/debug/kmemleak) # cat /sys/kernel/debug/kmemleak unreferenced object 0xffff888cd8ca2c40 (size 64): comm "hackbench", pid 17142, jiffies 4299780315 hex dump (first 32 bytes): ac 74 49 00 01 00 00 00 4c 84 49 00 01 00 00 00 .tI.....L.I..... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc bff18fd4): [<ffffffff81419a89>] __kmalloc_cache_noprof+0x2f9/0x3f0 [<ffffffff8113f715>] task_numa_work+0x725/0xa00 [<ffffffff8110f878>] task_work_run+0x58/0x90 [<ffffffff81ddd9f8>] syscall_exit_to_user_mode+0x1c8/0x1e0 [<ffffffff81dd78d5>] do_syscall_64+0x85/0x150 [<ffffffff81e0012b>] entry_SYSCALL_64_after_hwframe+0x76/0x7e ... This issue can be consistently reproduced on three different servers: * a 448-core server * a 256-core server * a 192-core server [Root Cause] Since multiple threads are created by the hackbench program (along with the command argument 'thread'), a shared vma might be accessed by two or more cores simultaneously. When two or more cores observe that vma->numab_state is NULL at the same time, vma->numab_state will be overwritten. Although current code ensures that only one thread scans the VMAs in a single 'numa_scan_period', there might be a chance for another thread to enter in the next 'numa_scan_period' while we have not gotten till numab_state allocation [1]. Note that the command `/opt/ltp/testcases/bin/hackbench 50 process 1000` cannot the reproduce the issue. It is verified with 200+ test runs. [Solution] Use the cmpxchg atomic operation to ensure that only one thread executes the vma->numab_state assignment. [1] https://lore.kernel.org/lkml/1794be3c-358c-4cdc-a43d-a1f841d91ef7@amd.com/

Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Never miss a vulnerability like this again

Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.

Read MoreStart Free Trial

• agent/title
• agent/type
• agent/first-publish-date
• agent/author
• agent/weakness
• agent/severity
• agent/remedy
• collector/mitre-cve
• source/MITRE
• agent/last-modified-date
• collector/nvd-api
• source/NVD
• agent/software-canonical-lookup
• agent/software-canonical-lookup-request
• collector/usn-cve
• source/Ubuntu
• collector/launchpad-cve
• source/Launchpad
• agent/references
• agent/source
• agent/description
• agent/softwarecombine
• agent/tags
• agent/event
• collector/security-tracker-debian
• source/Debian
• collector/nvd-cve
• vendor/linux
• canonical/linux kernel
• version/linux kernel/6.4
• version/linux kernel/6.7
• version/linux kernel/6.13-rc1
• package-manager/debian