mm/kmemleak: avoid soft lockup when scanning task stacks
In the Linux kernel, the following vulnerability has been resolved: mm/kmemleak: avoid soft lockup when scanning task stacks Patch series "mm/kmemleak: avoid soft lockup when scanning task", v3. kmemleak_scan() scans every task stack under one rcu_read_lock() with no reschedule point, which can trip the soft lockup watchdog on hosts with very many threads. That prints the following message, depending on the workload+host configuration: watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537] scan_block kmemleak_scan kmemleak_scan_thread kthread Patch 1 walks the tasks with find_ge_pid() so the scan reschedules between tasks Patches 2-3 let the scan loops stop early once a scan is interrupted. This patch (of 3): kmemleak_scan() walks every thread and scans its kernel stack under a single rcu_read_lock() with no reschedule point. On a host with very many threads -- amplified by KASAN/lockdep in debug builds -- this loop can hog a CPU long enough to trip the soft lockup watchdog: watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537] scan_block kmemleak_scan kmemleak_scan_thread kthread A cond_resched() cannot be added directly: the loop runs inside an RCU read-side critical section. Walk the tasks one PID at a time with find_ge_pid(), taking the RCU read lock only to look up and pin each task. The stack is then scanned with no lock held, so cond_resched() runs between tasks and the scan stops early on scan_should_stop(). This follows the next_tgid()/task_seq
CVE-2026-89759
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-89759
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
"lessThan": "f1cd6c4c35243377882c47236281d03ee3be6eeb",
"versionType": "git"
},
{
"status": "affected",
"version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
"lessThan": "9a1b12c06c192290b8479de48f66f1e75d89c4b7",
"versionType": "git"
},
{
"status": "affected",
"version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
"lessThan": "3fc8044251de21555fb02c365fa681bab8b0db55",
"versionType": "git"
},
{
"status": "affected",
"version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
"lessThan": "1838c704bcb4fd3556cf67513c6f97a39099e35c",
"versionType": "git"
},
{
"status": "affected",
"version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
"lessThan": "5d10d4e19e6daa487f0cd0ea6cba472325de92f9",
"versionType": "git"
}
],
"programFiles": [
"mm/kmemleak.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.10"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.10",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.109",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"mm/kmemleak.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89759
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #46721 · Revision 1
- Added to Heist Feed
- Publisher date