sunvdc: unmap LDC cookies when the descriptor send fails

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-97952
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-25 11:17:22 UTC
Updated2026-09-25 11:17:22 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: sunvdc: unmap LDC cookies when the descriptor send fails __send_request() maps the request's pages into the LDC channel's map table (ldc_map_sg()), fills in the descriptor and marks it VIO_DESC_READY before ringing the doorbell via __vdc_tx_trigger(). When the trigger fails, the error path only prints a message: the descriptor stays READY and the cookies are never unmapped. The mapping is normally released in vdc_end_one() when the peer completes the descriptor - but a descriptor whose doorbell was never sent will never complete, and since dr->prod is not advanced on failure, the reset path (vdc_requeue_inflight(), which walks [cons, prod)) never visits it either. The map table entries are leaked permanently. Since commit a11f6ca9aef9 ("sunvdc: Do not spin in an infinite loop when vio_ldc_send() returns EAGAIN") trigger failures occur in practice under load, so every resulting I/O error also leaks one request's worth of entries from the fixed-size (8192 entries per channel) map table. Because the allocator hands out contiguous ranges, fragmentation makes large multi-segment requests fail first as the table drains, until ldc_map_sg() fails permanently and the disk is dead until reboot. It also makes any retry-based recovery unusable: requeuing the request on -EAGAIN remaps the pages on every attempt, overwriting desc->cookies and orphaning the previous mapping, so the table drains at the retry rate. This is the memory exhaustion observed when the requeue approach was first tested in October 2025. Roll back on failure: unmap the cookies, mark the descriptor FREE again and clear the request entry. If the trigger failed with -ENOTCONN, __vdc_tx_trigger() has already reset the port, which tears down and reallocates both the dring and the LDC channel including its map table - nothing to roll back, and the stale descriptor must not be touched.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec ab81a5c1014a38dab0fb402609fd866b0bcb4726 git Not specified
CNA Linux Linux affected a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec 57835952566f0be9b365a6eb3a70b397a9d5ef47 git Not specified
CNA Linux Linux affected a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec f3322baa3a8ac87730feae952c1146269d78e098 git Not specified
CNA Linux Linux affected a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec 0c6da21fa35e03fc74f09895433ccd6d4a9c3530 git Not specified
CNA Linux Linux affected 627e656239c63d8a81672d08de7885e89c12fa75 git Not specified
CNA Linux Linux affected a1ef7d5da9b2c145f811a80bb8197df6037a7572 git Not specified
CNA Linux Linux affected 7ab4b6526fdcdfa7772984bbcd2ac4fd14fa223b git Not specified
CNA Linux Linux affected 3fbba4e55051d01a72b56ea192064175924bf56a git Not specified
CNA Linux Linux affected 3e380fc2ae4d18210eec9c472b12e2b2544f7dc1 git Not specified
CNA Linux Linux affected 4.4.175 4.5 semver Not specified
CNA Linux Linux affected 4.9.156 4.10 semver Not specified
CNA Linux Linux affected 4.14.99 4.15 semver Not specified
CNA Linux Linux affected 4.19.21 4.20 semver Not specified
CNA Linux Linux affected 4.20.8 4.21 semver Not specified
CNA Linux Linux affected 5.0 Not specified
CNA Linux Linux unaffected 5.0 semver Not specified
CNA Linux Linux unaffected 6.12.111 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.53 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.7 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc3 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/0c6da21fa35e03fc74f09895433ccd6d4a9c3530 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ab81a5c1014a38dab0fb402609fd866b0bcb4726 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/57835952566f0be9b365a6eb3a70b397a9d5ef47 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f3322baa3a8ac87730feae952c1146269d78e098 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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