{"id":"AZL-97146","summary":"CVE-2026-74601 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Use current_context for safe per-CPU buffer swap\n\nThe ring_buffer_swap_cpu() function currently checks the per-CPU\ncommitting counter to determine if a buffer is actively being written to\nbefore performing the swap. However, there exists a race window where\nthis check can be bypassed:\n\n    ring_buffer_lock_reserve\n        cpu_buffer = buffer-\u003ebuffers[cpu];       // cpu_buffer_a\n        rb_reserve_next_event\n            rb_start_commit // inc committing\n            if (unlikely(READ_ONCE(cpu_buffer-\u003ebuffer) != buffer)) {...}\n            __rb_reserve_next\n                rb_move_tail\n                    rb_end_commit(cpu_buffer);   // dec committing =\u003e 0\n                    /* interrupt hits here, successfully swaps! */\n                    local_inc(&cpu_buffer-\u003ecommitting);\n\n    ring_buffer_unlock_commit\n        cpu_buffer = buffer-\u003ebuffers[cpu];      // cpu_buffer_b\n        rb_commit\n            rb_end_commit\n            RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer-\u003ecommitting))\n                                                // triggers warning\n\nThe committing counter can temporarily drop to 0 during a single write\noperation (within rb_move_tail), creating a window where swap can\nsucceed even though the write is still in progress. This leads to\ninconsistent buffer state and triggers the RB_WARN_ON in rb_commit().\n\nReplace the committing counter check with current_context checks, which\nare set at the entry of ring_buffer_lock_reserve() and remain valid\nthroughout the entire write operation, providing a reliable indicator of\nbuffer busy state during swap.","modified":"2026-08-30T05:26:50Z","published":"2026-08-22T16:16:32Z","upstream":["CVE-2026-74601"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74601"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-97146.json"}}],"schema_version":"1.9.0"}