{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2022-49214", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-02-26T01:49:39.292Z", "datePublished": "2025-02-26T01:55:49.677Z", "dateUpdated": "2026-05-11T18:55:21.234Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T18:55:21.234Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/64s: Don't use DSISR for SLB faults\n\nSince commit 46ddcb3950a2 (\"powerpc/mm: Show if a bad page fault on data\nis read or write.\") we use page_fault_is_write(regs->dsisr) in\n__bad_page_fault() to determine if the fault is for a read or write, and\nchange the message printed accordingly.\n\nBut SLB faults, aka Data Segment Interrupts, don't set DSISR (Data\nStorage Interrupt Status Register) to a useful value. All ISA versions\nfrom v2.03 through v3.1 specify that the Data Segment Interrupt sets\nDSISR \"to an undefined value\". As far as I can see there's no mention of\nSLB faults setting DSISR in any BookIV content either.\n\nThis manifests as accesses that should be a read being incorrectly\nreported as writes, for example, using the xmon \"dump\" command:\n\n 0:mon> d 0x5deadbeef0000000\n 5deadbeef0000000\n [359526.415354][ C6] BUG: Unable to handle kernel data access on write at 0x5deadbeef0000000\n [359526.415611][ C6] Faulting instruction address: 0xc00000000010a300\n cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf400]\n pc: c00000000010a300: mread+0x90/0x190\n\nIf we disassemble the PC, we see a load instruction:\n\n 0:mon> di c00000000010a300\n c00000000010a300 89490000 lbz r10,0(r9)\n\nWe can also see in exceptions-64s.S that the data_access_slb block\ndoesn't set IDSISR=1, which means it doesn't load DSISR into pt_regs. So\nthe value we're using to determine if the fault is a read/write is some\nstale value in pt_regs from a previous page fault.\n\nRework the printing logic to separate the SLB fault case out, and only\nprint read/write in the cases where we can determine it.\n\nThe result looks like eg:\n\n 0:mon> d 0x5deadbeef0000000\n 5deadbeef0000000\n [ 721.779525][ C6] BUG: Unable to handle kernel data access at 0x5deadbeef0000000\n [ 721.779697][ C6] Faulting instruction address: 0xc00000000014cbe0\n cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf390]\n\n 0:mon> d 0\n 0000000000000000\n [ 742.793242][ C6] BUG: Kernel NULL pointer dereference at 0x00000000\n [ 742.793316][ C6] Faulting instruction address: 0xc00000000014cbe0\n cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf390]" } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/powerpc/mm/fault.c" ], "versions": [ { "version": "46ddcb3950a28c0df4815e8dbb8d4b91d5d9f22d", "lessThan": "4a852ff9b7bea9c640540e2c1bc70bd3ba455d61", "status": "affected", "versionType": "git" }, { "version": "46ddcb3950a28c0df4815e8dbb8d4b91d5d9f22d", "lessThan": "a3dae36d632b2cf6eb20314273e512a96cb43c9a", "status": "affected", "versionType": "git" }, { "version": "46ddcb3950a28c0df4815e8dbb8d4b91d5d9f22d", "lessThan": "093449bb182db885dae816d62874cccab7a4c42a", "status": "affected", "versionType": "git" }, { "version": "46ddcb3950a28c0df4815e8dbb8d4b91d5d9f22d", "lessThan": "d4679ac8ea2e5078704aa1c026db36580cc1bf9a", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/powerpc/mm/fault.c" ], "versions": [ { "version": "5.5", "status": "affected" }, { "version": "0", "lessThan": "5.5", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.33", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.16.19", "lessThanOrEqual": "5.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.17.2", "lessThanOrEqual": "5.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.18", "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": "5.5", "versionEndExcluding": "5.15.33" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.16.19" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.17.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4a852ff9b7bea9c640540e2c1bc70bd3ba455d61" }, { "url": "https://git.kernel.org/stable/c/a3dae36d632b2cf6eb20314273e512a96cb43c9a" }, { "url": "https://git.kernel.org/stable/c/093449bb182db885dae816d62874cccab7a4c42a" }, { "url": "https://git.kernel.org/stable/c/d4679ac8ea2e5078704aa1c026db36580cc1bf9a" } ], "title": "powerpc/64s: Don't use DSISR for SLB faults", "x_generator": { "engine": "bippy-1.2.0" } } } }