CVE-2026-93168

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-93168", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-17T16:02:15.090Z", "datePublished": "2026-09-17T16:11:59.904Z", "dateUpdated": "2026-10-30T12:36:12.039Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:36:12.039Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndmaengine: xilinx_dma: Fix CPU stall in xilinx_dma_poll_timeout\n\nCurrently when calling xilinx_dma_poll_timeout with delay_us=0 and a\ncondition that is never fulfilled, the CPU busy-waits for prolonged time\nand the timeout triggers only with a massive delay causing a CPU stall.\n\nThis happens due to a huge underestimation of wall clock time in\npoll_timeout_us_atomic. Commit 7349a69cf312 (\"iopoll: Do not use\ntimekeeping in read_poll_timeout_atomic()\") changed the behavior to no\nlonger use ktime_get at the expense of underestimation of wall clock\ntime which appears to be very large for delay_us=0. Instead of timing\nout after approximately XILINX_DMA_LOOP_COUNT microseconds, the timeout\ntakes XILINX_DMA_LOOP_COUNT * 1000 * (time that the overhead of the for\nloop in poll_timeout_us_atomic takes) which is in the range of several\nminutes for XILINX_DMA_LOOP_COUNT=1000000. Fix this by using a non-zero\nvalue for delay_us. Use delay_us=10 to keep the delay in the hot path of\nstarting DMA transfers minimal but still avoid CPU stalls in case of\nunexpected hardware failures.\n\nOne-off measurement with delay_us=0 causes the cpu to busy wait around 7\nminutes in the timeout case. After applying this patch with delay_us=10\nthe measured timeout was 1053428 microseconds which is roughly\nequivalent to the expected 1000000 microseconds specified in\nXILINX_DMA_LOOP_COUNT.\n\nAdd a constant XILINX_DMA_POLL_DELAY_US for delay_us value."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/dma/xilinx/xilinx_dma.c"], "versions": [{"version": "9495f2648287029fb5545c34a0fa318426ebe84c", "lessThan": "4237b5cc181a17f5a2a797655c1ce2c64e01c550", "status": "affected", "versionType": "git"}, {"version": "9495f2648287029fb5545c34a0fa318426ebe84c", "lessThan": "2ba67aa183a3ce174d534425b67eda84f6e3c896", "status": "affected", "versionType": "git"}, {"version": "9495f2648287029fb5545c34a0fa318426ebe84c", "lessThan": "c30a26d4987a01e619449bf170f584c007e07d75", "status": "affected", "versionType": "git"}, {"version": "9495f2648287029fb5545c34a0fa318426ebe84c", "lessThan": "f786e7b3adbf3bd14964a1cedf9d55b6ad91dcd7", "status": "affected", "versionType": "git"}, {"version": "9495f2648287029fb5545c34a0fa318426ebe84c", "lessThan": "8b5654d317277e6e505c23f8fa7e415237fefc7f", "status": "affected", "versionType": "git"}, {"version": "9495f2648287029fb5545c34a0fa318426ebe84c", "lessThan": "aa99c4d1d63bbc26a5fc4c667d89b2595743c19d", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/dma/xilinx/xilinx_dma.c"], "versions": [{"version": "4.6", "status": "affected"}, {"version": "0", "lessThan": "4.6", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.114", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.6", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "6.6.160"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "6.12.114"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "6.18.57"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "7.2.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/4237b5cc181a17f5a2a797655c1ce2c64e01c550"}, {"url": "https://git.kernel.org/stable/c/2ba67aa183a3ce174d534425b67eda84f6e3c896"}, {"url": "https://git.kernel.org/stable/c/c30a26d4987a01e619449bf170f584c007e07d75"}, {"url": "https://git.kernel.org/stable/c/f786e7b3adbf3bd14964a1cedf9d55b6ad91dcd7"}, {"url": "https://git.kernel.org/stable/c/8b5654d317277e6e505c23f8fa7e415237fefc7f"}, {"url": "https://git.kernel.org/stable/c/aa99c4d1d63bbc26a5fc4c667d89b2595743c19d"}], "title": "dmaengine: xilinx_dma: Fix CPU stall in xilinx_dma_poll_timeout", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/dma/xilinx/xilinx_dma.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "4237b5cc181a17f5a2a797655c1ce2c64e01c550", "status": "affected", "version": "9495f2648287029fb5545c34a0fa318426ebe84c", "versionType": "git"}, {"lessThan": "2ba67aa183a3ce174d534425b67eda84f6e3c896", "status": "affected", "version": "9495f2648287029fb5545c34a0fa318426ebe84c", "versionType": "git"}, {"lessThan": "c30a26d4987a01e619449bf170f584c007e07d75", "status": "affected", "version": "9495f2648287029fb5545c34a0fa318426ebe84c", "versionType": "git"}, {"lessThan": "f786e7b3adbf3bd14964a1cedf9d55b6ad91dcd7", "status": "affected", "version": "9495f2648287029fb5545c34a0fa318426ebe84c", "versionType": "git"}, {"lessThan": "8b5654d317277e6e505c23f8fa7e415237fefc7f", "status": "affected", "version": "9495f2648287029fb5545c34a0fa318426ebe84c", "versionType": "git"}, {"lessThan": "aa99c4d1d63bbc26a5fc4c667d89b2595743c19d", "status": "affected", "version": "9495f2648287029fb5545c34a0fa318426ebe84c", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/dma/xilinx/xilinx_dma.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.6"}, {"lessThan": "4.6", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.191", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.160", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.114", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.57", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.6", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndmaengine: xilinx_dma: Fix CPU stall in xilinx_dma_poll_timeout\n\nCurrently when calling xilinx_dma_poll_timeout with delay_us=0 and a\ncondition that is never fulfilled, the CPU busy-waits for prolonged time\nand the timeout triggers only with a massive delay causing a CPU stall.\n\nThis happens due to a huge underestimation of wall clock time in\npoll_timeout_us_atomic. Commit 7349a69cf312 (\"iopoll: Do not use\ntimekeeping in read_poll_timeout_atomic()\") changed the behavior to no\nlonger use ktime_get at the expense of underestimation of wall clock\ntime which appears to be very large for delay_us=0. Instead of timing\nout after approximately XILINX_DMA_LOOP_COUNT microseconds, the timeout\ntakes XILINX_DMA_LOOP_COUNT * 1000 * (time that the overhead of the for\nloop in poll_timeout_us_atomic takes) which is in the range of several\nminutes for XILINX_DMA_LOOP_COUNT=1000000. Fix this by using a non-zero\nvalue for delay_us. Use delay_us=10 to keep the delay in the hot path of\nstarting DMA transfers minimal but still avoid CPU stalls in case of\nunexpected hardware failures.\n\nOne-off measurement with delay_us=0 causes the cpu to busy wait around 7\nminutes in the timeout case. After applying this patch with delay_us=10\nthe measured timeout was 1053428 microseconds which is roughly\nequivalent to the expected 1000000 microseconds specified in\nXILINX_DMA_LOOP_COUNT.\n\nAdd a constant XILINX_DMA_POLL_DELAY_US for delay_us value."}], "id": "CVE-2026-93168", "lastModified": "2026-10-30T13:20:58.773", "metrics": {}, "published": "2026-09-17T17:18:12.403", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2ba67aa183a3ce174d534425b67eda84f6e3c896"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4237b5cc181a17f5a2a797655c1ce2c64e01c550"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8b5654d317277e6e505c23f8fa7e415237fefc7f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/aa99c4d1d63bbc26a5fc4c667d89b2595743c19d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c30a26d4987a01e619449bf170f584c007e07d75"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f786e7b3adbf3bd14964a1cedf9d55b6ad91dcd7"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9495f2648287029fb5545c34a0fa318426ebe84c,8b5654d317277e6e505c23f8fa7e415237fefc7f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9495f2648287029fb5545c34a0fa318426ebe84c,aa99c4d1d63bbc26a5fc4c667d89b2595743c19d)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4.6"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,4.6)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.6,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.3-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-19T07:45:06.232391+00:00", "updated": "2026-09-19T17:45:17.266495+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-399"]}