{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98644", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.362Z", "datePublished": "2026-10-18T15:20:15.380Z", "dateUpdated": "2026-10-19T09:23:13.963Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:23:13.963Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Avoid soft lockup in __htab_map_lookup_and_delete_batch()\n\n__htab_map_lookup_and_delete_batch() has no rescheduling point. The\nbatch count bounds how many entries are copied out, not how many\nbuckets are visited, so one BPF_MAP_LOOKUP_BATCH call can walk the\nmap end to end. The empty-bucket fast path is worse: it stays inside\na single rcu_read_lock() / bpf_disable_instrumentation() section for\nany run of consecutive empty buckets.\n\nThat holds up on small maps, but it falls apart at scale. On a\n144-CPU arm64 host running a CONFIG_PREEMPT_NONE kernel, periodic\nBPF_MAP_LOOKUP_BATCH calls against an LRU hash map with 16,777,216\nbuckets held a CPU inside the batch op for 77+ seconds and triggered\nthe soft lockup watchdog.\n\nCommit 75134f16e7dd (\"bpf: Add schedule points in batch ops\") fixed this\nsame problem in the generic batch ops, but not in this htab-native path,\nwhich every htab-based hash map variant uses for its lookup[_and_delete]\nbatch ops.\n\nComplete that fix here. Leave the critical section after 64 consecutive\nempty buckets, call cond_resched_tasks_rcu_qs(), and resume at the saved\nbucket cursor. No locks are held at that point, and resuming from the\ncursor is already the function's behavior for non-empty buckets. Add the\nsame call to the per-bucket loop after copy_to_user(), where every lock\nhas been dropped. cond_resched_rcu() is not enough here: sleeping with\nbpf_prog_active elevated makes tracing programs on that CPU silently\nskip their invocations.\n\nPlain cond_resched() is not enough either. It is a no-op under PREEMPT\nand PREEMPT_LAZY, the only models arm64 and x86 have offered since\ncommit 7dadeaa6e851 (\"sched: Further restrict the preemption modes\").\nIt is also never a Tasks RCU quiescent state, in any model: the\nreschedule counts as a preemption. The walking task stays a holdout and\nstalls every synchronize_rcu_tasks() caller, ftrace and BPF trampoline\nteardown included, until the syscall returns [1].\ncond_resched_tasks_rcu_qs() is the usual tool for that [2]. It reports\nthe quiescent state at each yield and still reschedules as\ncond_resched() does on PREEMPT_NONE and PREEMPT_VOLUNTARY kernels." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/hashtab.c" ], "versions": [ { "version": "057996380a42bb64ccc04383cfa9c0ace4ea11f0", "lessThan": "5c8b1869cb99a32a962388848cd19604fb41263e", "status": "affected", "versionType": "git" }, { "version": "057996380a42bb64ccc04383cfa9c0ace4ea11f0", "lessThan": "ca5bd55fc508fbb5c08c62206d02237a5b6fc7e8", "status": "affected", "versionType": "git" }, { "version": "057996380a42bb64ccc04383cfa9c0ace4ea11f0", "lessThan": "77a3b52b4455e6377e549539e757bc55eedefb51", "status": "affected", "versionType": "git" }, { "version": "057996380a42bb64ccc04383cfa9c0ace4ea11f0", "lessThan": "f0c09de08ec077098b7e1563f2285f1c136cd816", "status": "affected", "versionType": "git" }, { "version": "057996380a42bb64ccc04383cfa9c0ace4ea11f0", "lessThan": "44f9bcb5ab2b268bc763ed3ebec83308b4972936", "status": "affected", "versionType": "git" }, { "version": "057996380a42bb64ccc04383cfa9c0ace4ea11f0", "lessThan": "4e48fe9b1c77966bede0a73feb3059d7595f642d", "status": "affected", "versionType": "git" }, { "version": "057996380a42bb64ccc04383cfa9c0ace4ea11f0", "lessThan": "85136bf22404474a815fc0ed26ec0d1cbc1bc3f9", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/hashtab.c" ], "versions": [ { "version": "5.6", "status": "affected" }, { "version": "0", "lessThan": "5.6", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.222", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.189", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.158", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.55", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.9", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.6", "versionEndExcluding": "5.15.222" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.6", "versionEndExcluding": "6.1.189" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.6", "versionEndExcluding": "6.6.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.6", "versionEndExcluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.6", "versionEndExcluding": "6.18.55" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.6", "versionEndExcluding": "7.2.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.6", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5c8b1869cb99a32a962388848cd19604fb41263e" }, { "url": "https://git.kernel.org/stable/c/ca5bd55fc508fbb5c08c62206d02237a5b6fc7e8" }, { "url": "https://git.kernel.org/stable/c/77a3b52b4455e6377e549539e757bc55eedefb51" }, { "url": "https://git.kernel.org/stable/c/f0c09de08ec077098b7e1563f2285f1c136cd816" }, { "url": "https://git.kernel.org/stable/c/44f9bcb5ab2b268bc763ed3ebec83308b4972936" }, { "url": "https://git.kernel.org/stable/c/4e48fe9b1c77966bede0a73feb3059d7595f642d" }, { "url": "https://git.kernel.org/stable/c/85136bf22404474a815fc0ed26ec0d1cbc1bc3f9" } ], "title": "bpf: Avoid soft lockup in __htab_map_lookup_and_delete_batch()", "x_generator": { "engine": "bippy-1.2.0" } } } }