RDMA/ucma: Lock the handler in ucma_write_cm_event()
In the Linux kernel, the following vulnerability has been resolved: RDMA/ucma: Lock the handler in ucma_write_cm_event() ctx->file may only be changed under the handler lock and the xa_lock, which is what stops uevents being queued for a ctx while ucma_migrate_id() moves it to another file. The CM core takes that lock before invoking ucma_event_handler(), but the write() paths that queue uevents themselves do not. ucma_write_cm_event() re-reads ctx->file for each of its four dereferences, so ucma_migrate_id() can swap it mid-sequence: mutex_lock(&ctx->file->mut); /* file A */ list_add_tail(&uevent->list, &ctx->file->event_list); /* file B */ mutex_unlock(&ctx->file->mut); /* file B */ wake_up_interruptible(&ctx->file->poll_wait); /* file B */ The window is the mutex_lock() itself: the writer sleeps in it while the migration reassigns ctx->file. The list_add_tail() then runs on file B's event_list holding only file A's mutex: list_add corruption. prev->next should be next (ffff888101320f30), but was ffff88814a08c418. (prev=ffff88814a075c18). kernel BUG at lib/list_debug.c:32! Call Trace: ucma_write_cm_event+0x36e/0x5e0 and file A's mut is left held forever, wedging its next writer in D state. The uevent is also stranded on a list ucma_cleanup_ctx_events() will not walk, so it outlives its context. /dev/infiniband/rdma_cm is 0666 and no RDMA device is involved, so an unprivileged user reaches all of this. Take the handler lock, as ucma_cleanup_mc_events() does; ctx->cm_id is pi
CVE-2026-89507
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-2026-89507
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": "a3c9d0fcd3715541bbf97da2ddde9d032e2fe6d5",
"lessThan": "4f8bb11dd2ff365e7cff1c9964ab4607292d364e",
"versionType": "git"
},
{
"status": "affected",
"version": "a3c9d0fcd3715541bbf97da2ddde9d032e2fe6d5",
"lessThan": "0be1955040a2eceed0ecfc387fdc92305411d273",
"versionType": "git"
},
{
"status": "affected",
"version": "a3c9d0fcd3715541bbf97da2ddde9d032e2fe6d5",
"lessThan": "f4cc21c6a8e9d392871477f9fd98d68e5ad80272",
"versionType": "git"
}
],
"programFiles": [
"drivers/infiniband/core/ucma.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.18"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.18",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/infiniband/core/ucma.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89507
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #35034 · Revision 1
- Added to Heist Feed
- Publisher date