ghsa-74hg-7r85-vvw3
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
PCI: aardvark: Fix kernel panic during PIO transfer
Trying to start a new PIO transfer by writing value 0 in PIO_START register when previous transfer has not yet completed (which is indicated by value 1 in PIO_START) causes an External Abort on CPU, which results in kernel panic:
SError Interrupt on CPU0, code 0xbf000002 -- SError
Kernel panic - not syncing: Asynchronous SError Interrupt
To prevent kernel panic, it is required to reject a new PIO transfer when previous one has not finished yet.
If previous PIO transfer is not finished yet, the kernel may issue a new PIO request only if the previous PIO transfer timed out.
In the past the root cause of this issue was incorrectly identified (as it often happens during link retraining or after link down event) and special hack was implemented in Trusted Firmware to catch all SError events in EL3, to ignore errors with code 0xbf000002 and not forwarding any other errors to kernel and instead throw panic from EL3 Trusted Firmware handler.
Links to discussion and patches about this issue: https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/commit/?id=3c7dcdac5c50 https://lore.kernel.org/linux-pci/20190316161243.29517-1-repk@triplefau.lt/ https://lore.kernel.org/linux-pci/971be151d24312cc533989a64bd454b4@www.loen.fr/ https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/1541
But the real cause was the fact that during link retraining or after link down event the PIO transfer may take longer time, up to the 1.44s until it times out. This increased probability that a new PIO transfer would be issued by kernel while previous one has not finished yet.
After applying this change into the kernel, it is possible to revert the mentioned TF-A hack and SError events do not have to be caught in TF-A EL3.
{
"affected": [],
"aliases": [
"CVE-2021-47229"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-21T15:15:12Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nPCI: aardvark: Fix kernel panic during PIO transfer\n\nTrying to start a new PIO transfer by writing value 0 in PIO_START register\nwhen previous transfer has not yet completed (which is indicated by value 1\nin PIO_START) causes an External Abort on CPU, which results in kernel\npanic:\n\n SError Interrupt on CPU0, code 0xbf000002 -- SError\n Kernel panic - not syncing: Asynchronous SError Interrupt\n\nTo prevent kernel panic, it is required to reject a new PIO transfer when\nprevious one has not finished yet.\n\nIf previous PIO transfer is not finished yet, the kernel may issue a new\nPIO request only if the previous PIO transfer timed out.\n\nIn the past the root cause of this issue was incorrectly identified (as it\noften happens during link retraining or after link down event) and special\nhack was implemented in Trusted Firmware to catch all SError events in EL3,\nto ignore errors with code 0xbf000002 and not forwarding any other errors\nto kernel and instead throw panic from EL3 Trusted Firmware handler.\n\nLinks to discussion and patches about this issue:\nhttps://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/commit/?id=3c7dcdac5c50\nhttps://lore.kernel.org/linux-pci/20190316161243.29517-1-repk@triplefau.lt/\nhttps://lore.kernel.org/linux-pci/971be151d24312cc533989a64bd454b4@www.loen.fr/\nhttps://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/1541\n\nBut the real cause was the fact that during link retraining or after link\ndown event the PIO transfer may take longer time, up to the 1.44s until it\ntimes out. This increased probability that a new PIO transfer would be\nissued by kernel while previous one has not finished yet.\n\nAfter applying this change into the kernel, it is possible to revert the\nmentioned TF-A hack and SError events do not have to be caught in TF-A EL3.",
"id": "GHSA-74hg-7r85-vvw3",
"modified": "2025-04-29T21:31:34Z",
"published": "2024-05-21T15:31:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47229"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1a1dbc4473974867fe8c5f195c17b341c8e82867"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3d213a4ddf49a860be6e795482c17f87e0c82b2a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/400e6b1860c8be61388d0b77814c53260f96e17a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4c90f90a91d75c3c73dd633827c90e8746d9f54d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b00a9aaa4be20ad6e3311fb78a485eae0899e89a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f18139966d072dab8e4398c95ce955a9742e04f7"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.