{"id":"CVE-2026-90342","state":"PUBLISHED","title":"bpf: Fix mmap_lock deadlock on arena lock failure","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix mmap_lock deadlock on arena lock failure\n\nReported by the Sashiko AI review.\n\narena_vm_fault() returns VM_FAULT_RETRY when it can't take\narena->spinlock, but it never took mmap_lock. The fault path assumes a\nVM_FAULT_RETRY handler already dropped mmap_lock and re-takes it on the\nretry, so mmap_lock gets taken twice and can deadlock:\n\n\tdo_user_addr_fault()\n\t{\n\t\tfault = handle_mm_fault(...);   // calls arena_vm_fault()\n\t\tif (fault & VM_FAULT_RETRY)\n\t\t\tgoto retry;   // re-locks mmap_lock\n\t\tmmap_read_unlock(mm);\n\t}\n\nReturn VM_FAULT_SIGBUS instead, for two reasons:\n\n1. We could keep VM_FAULT_RETRY, but then we'd have to drop the fault\n   lock first and cap the retry ourselves, the way __folio_lock_or_retry()\n   does.\n\n2. A failed raw_res_spin_lock_irqsave() already means a possible deadlock\n   was detected, so retrying just hits the same lock again.\n\nSo returning VM_FAULT_RETRY here is overkill.","publishedAt":"2026-09-17T16:08:53.010Z","updatedAt":"2026-10-19T09:01:59.207Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b8467290edab4bafae352bf3f317055669a1a458","status":"affected","lessThan":"af8087f16714f7620c4db3e732baaa1b2337948f","versionType":"git"},{"version":"b8467290edab4bafae352bf3f317055669a1a458","status":"affected","lessThan":"0b10b945479c954393d62ee3229d2f224a4ca91c","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/arena.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.0","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/arena.c"]}],"references":["https://git.kernel.org/stable/c/af8087f16714f7620c4db3e732baaa1b2337948f","https://git.kernel.org/stable/c/0b10b945479c954393d62ee3229d2f224a4ca91c"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90342.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90342","state":"PUBLISHED","datePublished":"2026-09-17T16:08:53.010Z","dateUpdated":"2026-10-19T09:01:59.207Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.804Z"},"containers":{"cna":{"title":"bpf: Fix mmap_lock deadlock on arena lock failure","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix mmap_lock deadlock on arena lock failure\n\nReported by the Sashiko AI review.\n\narena_vm_fault() returns VM_FAULT_RETRY when it can't take\narena->spinlock, but it never took mmap_lock. The fault path assumes a\nVM_FAULT_RETRY handler already dropped mmap_lock and re-takes it on the\nretry, so mmap_lock gets taken twice and can deadlock:\n\n\tdo_user_addr_fault()\n\t{\n\t\tfault = handle_mm_fault(...);   // calls arena_vm_fault()\n\t\tif (fault & VM_FAULT_RETRY)\n\t\t\tgoto retry;   // re-locks mmap_lock\n\t\tmmap_read_unlock(mm);\n\t}\n\nReturn VM_FAULT_SIGBUS instead, for two reasons:\n\n1. We could keep VM_FAULT_RETRY, but then we'd have to drop the fault\n   lock first and cap the retry ourselves, the way __folio_lock_or_retry()\n   does.\n\n2. A failed raw_res_spin_lock_irqsave() already means a possible deadlock\n   was detected, so retrying just hits the same lock again.\n\nSo returning VM_FAULT_RETRY here is overkill."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b8467290edab4bafae352bf3f317055669a1a458","status":"affected","lessThan":"af8087f16714f7620c4db3e732baaa1b2337948f","versionType":"git"},{"version":"b8467290edab4bafae352bf3f317055669a1a458","status":"affected","lessThan":"0b10b945479c954393d62ee3229d2f224a4ca91c","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/arena.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.0","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/arena.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/af8087f16714f7620c4db3e732baaa1b2337948f"},{"url":"https://git.kernel.org/stable/c/0b10b945479c954393d62ee3229d2f224a4ca91c"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:01:59.207Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}