mailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler
In the Linux kernel, the following vulnerability has been resolved: mailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler qcom_cpucp_mbox_irq_fn() calls mbox_chan_received_data() while holding chan->lock. Under PREEMPT_RT, spin_lock_irqsave() is converted to an rt_spinlock (rtmutex-based), which tracks ownership and can sleep. The callback chain triggered by mbox_chan_received_data() eventually reaches mailbox_clear_channel() -> mbox_send_message() -> add_to_rbuf(), which attempts to re-acquire the same chan->lock. Since rtmutex detects the re-entrant lock attempt by the same owner, the thread blocks waiting for a lock it already holds, causing a permanent deadlock. This deadlock manifests as 'irq/N-apss_cpucp_mbox' stuck in D state with the following call trace: rt_spin_lock -> mbox_send_message -> mailbox_clear_channel -> scmi_rx_callback -> mbox_chan_received_data [<- held chan->lock here] Fix by saving chan->cl locally and clearing the HW interrupt register inside the lock, then invoking mbox_chan_received_data() after releasing the lock. This preserves the mutual exclusion for chan->cl access while avoiding the lock re-entrancy that causes the PREEMPT_RT deadlock.
CVE-2026-90193
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-2026-90193
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": "0e2a9a03106cd5fa0dbc9047675e7645c55e2669",
"lessThan": "aa482273f32117c3adeba9b1cc945e0b5d33722d",
"versionType": "git"
},
{
"status": "affected",
"version": "0e2a9a03106cd5fa0dbc9047675e7645c55e2669",
"lessThan": "8b8de6400c86937ed57d680d06d716e167b381de",
"versionType": "git"
},
{
"status": "affected",
"version": "0e2a9a03106cd5fa0dbc9047675e7645c55e2669",
"lessThan": "e40b3edeaf25cd09e9c88edb1ef99373ca37593b",
"versionType": "git"
},
{
"status": "affected",
"version": "0e2a9a03106cd5fa0dbc9047675e7645c55e2669",
"lessThan": "3690aaa6d18f6775c3e7932fb8af8c5bf6a6b69c",
"versionType": "git"
}
],
"programFiles": [
"drivers/mailbox/qcom-cpucp-mbox.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.11"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.11",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.110",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.52",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.6",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/mailbox/qcom-cpucp-mbox.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-90193
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #36571 · Revision 1
- Added to Heist Feed
- Publisher date