Skip to main content
cve.nowby Sazabi
← All vulnerabilities
CVE-2026-97952

sunvdc: unmap LDC cookies when the descriptor send fails

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.5, 4.10, 4.15, 4.20, 4.21, and 7 more
None on Exploit-DB, Metasploit or GitHub

Summary

In 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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec · fixed in eb9c5f6747fe98b83c78cb5476a914e91d50e8e8; From a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec · fixed in 24564576be423f3b5d7e67cd7df848ac66646497; From a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec · fixed in 9251573e7cf7d797ae4a30b2a236af8242237a61; From a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec · fixed in b0de6463667e9bb9dc14a83a9c24c1b6b3f7b5f7; From a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec · fixed in ab81a5c1014a38dab0fb402609fd866b0bcb4726; From a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec · fixed in 57835952566f0be9b365a6eb3a70b397a9d5ef47; From a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec · fixed in f3322baa3a8ac87730feae952c1146269d78e098; From a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec · fixed in 0c6da21fa35e03fc74f09895433ccd6d4a9c3530; From 4.4.175 · fixed in 4.5; From 4.9.156 · fixed in 4.10; From 4.14.99 · fixed in 4.15; From 4.19.21 · fixed in 4.20; From 4.20.8 · fixed in 4.21

  • Linux Linux

    5.0

  • KernelLinux

    From 5.0.0 · fixed in 5.10.271; From 5.11.0 · fixed in 5.15.222; From 5.16.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.53; From 6.19.0 · fixed in 7.2.7

References 8

git.kernel.org