{"id":"CVE-2026-90193","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nmailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler\n\nqcom_cpucp_mbox_irq_fn() calls mbox_chan_received_data() while holding\nchan->lock","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nmailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler\n\nqcom_cpucp_mbox_irq_fn() calls mbox_chan_received_data() while holding\nchan->lock. Under PREEMPT_RT, s…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 < aa482273f32117c3adeba9b1cc945e0b5d33722d","Linux >= 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 < 8b8de6400c86937ed57d680d06d716e167b381de","Linux >= 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 < e40b3edeaf25cd09e9c88edb1ef99373ca37593b","Linux >= 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 < 3690aaa6d18f6775c3e7932fb8af8c5bf6a6b69c","Linux 6.11"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T17:17:14.030","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90193","references":[{"url":"https://git.kernel.org/stable/c/3690aaa6d18f6775c3e7932fb8af8c5bf6a6b69c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8b8de6400c86937ed57d680d06d716e167b381de","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/aa482273f32117c3adeba9b1cc945e0b5d33722d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e40b3edeaf25cd09e9c88edb1ef99373ca37593b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-17T16:21:47.862Z","epss":0.002,"epssPercentile":0.10171,"slug":"CVE-2026-90193","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nmailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler\n\nqcom_cpucp_mbox_irq_fn() calls mbox_chan_received_data() while holding\nchan->lock. Under PREEMPT_RT, spin_lock_irqsave() is converted to an\nrt_spinlock (rtmutex-based), which tracks ownership and can sleep.\n\nThe callback chain triggered by mbox_chan_received_data() eventually\nreaches mailbox_clear_channel() -> mbox_send_message() -> add_to_rbuf(),\nwhich attempts to re-acquire the same chan->lock. Since rtmutex detects\nthe re-entrant lock attempt by the same owner, the thread blocks waiting\nfor a lock it already holds, causing a permanent deadlock.\n\nThis deadlock manifests as 'irq/N-apss_cpucp_mbox' stuck in D state\nwith the following call trace:\n  rt_spin_lock -> mbox_send_message -> mailbox_clear_channel ->\n  scmi_rx_callback -> mbox_chan_received_data [<- held chan->lock here]\n\nFix by saving chan->cl locally and clearing the HW interrupt register\ninside the lock, then invoking mbox_chan_received_data() after releasing\nthe lock. This preserves the mutual exclusion for chan->cl access while\navoiding the lock re-entrancy that causes the PREEMPT_RT deadlock.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}