Vulnerability-Lookup

GHSA-2HC3-VPVV-MWV3

Vulnerability from github – Published: 2026-08-06 09:30 – Updated: 2026-08-06 09:30

Details

In the Linux kernel, the following vulnerability has been resolved:

btrfs: do not trim a device which is not writeable

[BUG] There is a bug report that btrfs/242 can randomly fail with the following NULL pointer dereference:

run fstests btrfs/242 at 2026-06-01 10:25:08 BTRFS: device fsid d4d7f234-487c-4787-88e4-47a8b68c9874 devid 1 transid 9 /dev/sdc (8:32) scanned by mount (122609) BTRFS info (device sdc): first mount of filesystem d4d7f234-487c-4787-88e4-47a8b68c9874 BTRFS info (device sdc): using crc32c checksum algorithm BTRFS warning (device sdc): devid 2 uuid fbe72d72-3272-482d-80fb-ab88ed398192 is missing BTRFS warning (device sdc): devid 2 uuid fbe72d72-3272-482d-80fb-ab88ed398192 is missing BTRFS info (device sdc): allowing degraded mounts BTRFS info (device sdc): turning on async discard BTRFS info (device sdc): enabling free space tree Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018 user pgtable: 4k pages, 48-bit VAs, pgdp=000000013fd6b000 CPU: 4 UID: 0 PID: 122625 Comm: fstrim Not tainted 7.0.10-2-default #1 PREEMPT(full) openSUSE Tumbleweed e9a5f6b24978fba3bf015a992f865837fdfff3dd Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20250812-19.fc42 08/12/2025 pstate: 01400005 (nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) pc : btrfs_trim_fs+0x34c/0xa00 [btrfs] lr : btrfs_trim_fs+0x1f0/0xa00 [btrfs] Call trace: btrfs_trim_fs+0x34c/0xa00 [btrfs f02c1d570ceea621c69d302ba75dd61868083840] (P) btrfs_ioctl_fitrim+0xe8/0x178 [btrfs f02c1d570ceea621c69d302ba75dd61868083840] btrfs_ioctl+0xdd4/0x2bd8 [btrfs f02c1d570ceea621c69d302ba75dd61868083840] __arm64_sys_ioctl+0xac/0x108 invoke_syscall.constprop.0+0x5c/0xd0 el0_svc_common.constprop.0+0x40/0xf0 do_el0_svc+0x24/0x40 el0_svc+0x40/0x1d0 el0t_64_sync_handler+0xa0/0xe8 el0t_64_sync+0x1b0/0x1b8 Code: 17ffff83 f94017e0 f9002be0 f9402ea0 (f9400c00) ---[ end trace 0000000000000000 ]---

Also the reporter is very kind to test the following ASSERT() added to btrfs_trim_free_extents_throttle():

ASSERT(device->bdev,
       "devid=%llu path=%s dev_state=0x%lx\n",
       device->devid, btrfs_dev_name(device), device->dev_state);

And it shows the following output:

assertion failed: device->bdev, in extent-tree.c:6630 (devid=2 path=/dev/sdd dev_state=0x82)

Which means the device->bdev is NULL, and the dev_state is BTRFS_DEV_STATE_IN_FS_METADATA | BTRFS_DEV_STATE_ITEM_FOUND, without BTRFS_DEV_STATE_WRITEABLE flag set.

[CAUSE] The pc points to the following call chain:

btrfs_trim_fs() |- btrfs_trim_free_extents() |- btrfs_trim_free_extents_throttle() |- bdev_max_discard_sectors(device->bdev)

So the NULL pointer dereference is caused by device->bdev being NULL.

This looks impossible by a quick glance, as just before calling btrfs_trim_free_extents_throttle(), we have skipped any device that has BTRFS_DEV_STATE_MISSING flag set.

However in this particular case, there is a window where the missing device is later re-scanned, causing btrfs to remove the BTRFS_DEV_STATE_MISSING flag:

btrfs_control_ioctl() |- btrfs_scan_one_device() |- device_list_add() |- rcu_assign_pointer(device->name, name); | This updates the missing device's path to the new good path. | |- clear_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state) This removes the BTRFS_DEV_STATE_MISSING flag.

This allows the missing device to re-appear and clear the BTRFS_DEV_STATE_MISSING flag. However the device still does not have the BTRFS_DEV_STATE_WRITEABLE flag set, nor is its bdev pointer updated.

The bdev pointer remains NULL, triggering the crash later.

[FIX] This is a big de-synchronization between BTRFS_DEV_STATE_MISSING and device->bdev pointer, and shows a gap in btrfs's re-appearing-device handling.

The proper handling of re-appearing device will need quite some extra work, which is out of the context of this small ---truncated---

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64593"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-06T08:16:34Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: do not trim a device which is not writeable\n\n[BUG]\nThere is a bug report that btrfs/242 can randomly fail with the\nfollowing NULL pointer dereference:\n\n  run fstests btrfs/242 at 2026-06-01 10:25:08\n  BTRFS: device fsid d4d7f234-487c-4787-88e4-47a8b68c9874 devid 1 transid 9 /dev/sdc (8:32) scanned by mount (122609)\n  BTRFS info (device sdc): first mount of filesystem d4d7f234-487c-4787-88e4-47a8b68c9874\n  BTRFS info (device sdc): using crc32c checksum algorithm\n  BTRFS warning (device sdc): devid 2 uuid fbe72d72-3272-482d-80fb-ab88ed398192 is missing\n  BTRFS warning (device sdc): devid 2 uuid fbe72d72-3272-482d-80fb-ab88ed398192 is missing\n  BTRFS info (device sdc): allowing degraded mounts\n  BTRFS info (device sdc): turning on async discard\n  BTRFS info (device sdc): enabling free space tree\n  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018\n  user pgtable: 4k pages, 48-bit VAs, pgdp=000000013fd6b000\n  CPU: 4 UID: 0 PID: 122625 Comm: fstrim Not tainted 7.0.10-2-default #1 PREEMPT(full) openSUSE Tumbleweed e9a5f6b24978fba3bf015a992f865837fdfff3dd\n  Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20250812-19.fc42 08/12/2025\n  pstate: 01400005 (nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)\n  pc : btrfs_trim_fs+0x34c/0xa00 [btrfs]\n  lr : btrfs_trim_fs+0x1f0/0xa00 [btrfs]\n  Call trace:\n   btrfs_trim_fs+0x34c/0xa00 [btrfs f02c1d570ceea621c69d302ba75dd61868083840] (P)\n   btrfs_ioctl_fitrim+0xe8/0x178 [btrfs f02c1d570ceea621c69d302ba75dd61868083840]\n   btrfs_ioctl+0xdd4/0x2bd8 [btrfs f02c1d570ceea621c69d302ba75dd61868083840]\n   __arm64_sys_ioctl+0xac/0x108\n   invoke_syscall.constprop.0+0x5c/0xd0\n   el0_svc_common.constprop.0+0x40/0xf0\n   do_el0_svc+0x24/0x40\n   el0_svc+0x40/0x1d0\n   el0t_64_sync_handler+0xa0/0xe8\n   el0t_64_sync+0x1b0/0x1b8\n  Code: 17ffff83 f94017e0 f9002be0 f9402ea0 (f9400c00)\n  ---[ end trace 0000000000000000  ]---\n\nAlso the reporter is very kind to test the following ASSERT() added to\nbtrfs_trim_free_extents_throttle():\n\n\tASSERT(device-\u003ebdev,\n\t       \"devid=%llu path=%s dev_state=0x%lx\\n\",\n\t       device-\u003edevid, btrfs_dev_name(device), device-\u003edev_state);\n\nAnd it shows the following output:\n\n  assertion failed: device-\u003ebdev, in extent-tree.c:6630 (devid=2 path=/dev/sdd dev_state=0x82)\n\nWhich means the device-\u003ebdev is NULL, and the dev_state is\nBTRFS_DEV_STATE_IN_FS_METADATA | BTRFS_DEV_STATE_ITEM_FOUND, without\nBTRFS_DEV_STATE_WRITEABLE flag set.\n\n[CAUSE]\nThe pc points to the following call chain:\n\n  btrfs_trim_fs()\n  |- btrfs_trim_free_extents()\n     |- btrfs_trim_free_extents_throttle()\n        |- bdev_max_discard_sectors(device-\u003ebdev)\n\nSo the NULL pointer dereference is caused by device-\u003ebdev being NULL.\n\nThis looks impossible by a quick glance, as just before calling\nbtrfs_trim_free_extents_throttle(), we have skipped any device that has\nBTRFS_DEV_STATE_MISSING flag set.\n\nHowever in this particular case, there is a window where the missing\ndevice is later re-scanned, causing btrfs to remove the\nBTRFS_DEV_STATE_MISSING flag:\n\n  btrfs_control_ioctl()\n  |- btrfs_scan_one_device()\n     |- device_list_add()\n        |- rcu_assign_pointer(device-\u003ename, name);\n        |  This updates the missing device\u0027s path to the new good path.\n        |\n        |- clear_bit(BTRFS_DEV_STATE_MISSING, \u0026device-\u003edev_state)\n           This removes the BTRFS_DEV_STATE_MISSING flag.\n\nThis allows the missing device to re-appear and clear the\nBTRFS_DEV_STATE_MISSING flag.  However the device still does not have\nthe BTRFS_DEV_STATE_WRITEABLE flag set, nor is its bdev pointer updated.\n\nThe bdev pointer remains NULL, triggering the crash later.\n\n[FIX]\nThis is a big de-synchronization between BTRFS_DEV_STATE_MISSING and\ndevice-\u003ebdev pointer, and shows a gap in btrfs\u0027s re-appearing-device\nhandling.\n\nThe proper handling of re-appearing device will need quite some extra\nwork, which is out of the context of this small\n---truncated---",
  "id": "GHSA-2hc3-vpvv-mwv3",
  "modified": "2026-08-06T09:30:33Z",
  "published": "2026-08-06T09:30:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64593"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/02c903fc6fc7e16c5d1f22d18784f1208acf43e3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1b1937eb08f51319bf71575484cde2b8c517aedc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/210af872eafa0cf572a84cb303c0f9d2914c1226"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3d8fa4b828a86b33c60858e58aaab6df273ede05"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7a64521802997257b144e6edfb4e278dbeb972dd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9c894159c5b8adc84072e3af0e55b0473a69564e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b4af31b898a948e29861cb0bae734058f9a49d9b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f41ae7e6664f3c4361129728f2c4d5f3ed995251"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-64593 (GCVE-0-2026-64593)

Vulnerability from cvelistv5 – Published: 2026-08-06 07:13 – Updated: 2026-08-06 07:13

Title

btrfs: do not trim a device which is not writeable

Summary

In the Linux kernel, the following vulnerability has been resolved: btrfs: do not trim a device which is not writeable [BUG] There is a bug report that btrfs/242 can randomly fail with the following NULL pointer dereference: run fstests btrfs/242 at 2026-06-01 10:25:08 BTRFS: device fsid d4d7f234-487c-4787-88e4-47a8b68c9874 devid 1 transid 9 /dev/sdc (8:32) scanned by mount (122609) BTRFS info (device sdc): first mount of filesystem d4d7f234-487c-4787-88e4-47a8b68c9874 BTRFS info (device sdc): using crc32c checksum algorithm BTRFS warning (device sdc): devid 2 uuid fbe72d72-3272-482d-80fb-ab88ed398192 is missing BTRFS warning (device sdc): devid 2 uuid fbe72d72-3272-482d-80fb-ab88ed398192 is missing BTRFS info (device sdc): allowing degraded mounts BTRFS info (device sdc): turning on async discard BTRFS info (device sdc): enabling free space tree Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018 user pgtable: 4k pages, 48-bit VAs, pgdp=000000013fd6b000 CPU: 4 UID: 0 PID: 122625 Comm: fstrim Not tainted 7.0.10-2-default #1 PREEMPT(full) openSUSE Tumbleweed e9a5f6b24978fba3bf015a992f865837fdfff3dd Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20250812-19.fc42 08/12/2025 pstate: 01400005 (nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) pc : btrfs_trim_fs+0x34c/0xa00 [btrfs] lr : btrfs_trim_fs+0x1f0/0xa00 [btrfs] Call trace: btrfs_trim_fs+0x34c/0xa00 [btrfs f02c1d570ceea621c69d302ba75dd61868083840] (P) btrfs_ioctl_fitrim+0xe8/0x178 [btrfs f02c1d570ceea621c69d302ba75dd61868083840] btrfs_ioctl+0xdd4/0x2bd8 [btrfs f02c1d570ceea621c69d302ba75dd61868083840] __arm64_sys_ioctl+0xac/0x108 invoke_syscall.constprop.0+0x5c/0xd0 el0_svc_common.constprop.0+0x40/0xf0 do_el0_svc+0x24/0x40 el0_svc+0x40/0x1d0 el0t_64_sync_handler+0xa0/0xe8 el0t_64_sync+0x1b0/0x1b8 Code: 17ffff83 f94017e0 f9002be0 f9402ea0 (f9400c00) ---[ end trace 0000000000000000 ]--- Also the reporter is very kind to test the following ASSERT() added to btrfs_trim_free_extents_throttle(): ASSERT(device->bdev, "devid=%llu path=%s dev_state=0x%lx\n", device->devid, btrfs_dev_name(device), device->dev_state); And it shows the following output: assertion failed: device->bdev, in extent-tree.c:6630 (devid=2 path=/dev/sdd dev_state=0x82) Which means the device->bdev is NULL, and the dev_state is BTRFS_DEV_STATE_IN_FS_METADATA | BTRFS_DEV_STATE_ITEM_FOUND, without BTRFS_DEV_STATE_WRITEABLE flag set. [CAUSE] The pc points to the following call chain: btrfs_trim_fs() |- btrfs_trim_free_extents() |- btrfs_trim_free_extents_throttle() |- bdev_max_discard_sectors(device->bdev) So the NULL pointer dereference is caused by device->bdev being NULL. This looks impossible by a quick glance, as just before calling btrfs_trim_free_extents_throttle(), we have skipped any device that has BTRFS_DEV_STATE_MISSING flag set. However in this particular case, there is a window where the missing device is later re-scanned, causing btrfs to remove the BTRFS_DEV_STATE_MISSING flag: btrfs_control_ioctl() |- btrfs_scan_one_device() |- device_list_add() |- rcu_assign_pointer(device->name, name); | This updates the missing device's path to the new good path. | |- clear_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state) This removes the BTRFS_DEV_STATE_MISSING flag. This allows the missing device to re-appear and clear the BTRFS_DEV_STATE_MISSING flag. However the device still does not have the BTRFS_DEV_STATE_WRITEABLE flag set, nor is its bdev pointer updated. The bdev pointer remains NULL, triggering the crash later. [FIX] This is a big de-synchronization between BTRFS_DEV_STATE_MISSING and device->bdev pointer, and shows a gap in btrfs's re-appearing-device handling. The proper handling of re-appearing device will need quite some extra work, which is out of the context of this small ---truncated---

Severity

No CVSS data available.

Assigner

Linux

References

8 references

URL	Tags
https://git.kernel.org/stable/c/f41ae7e6664f3c436…
https://git.kernel.org/stable/c/210af872eafa0cf57…
https://git.kernel.org/stable/c/3d8fa4b828a86b33c…
https://git.kernel.org/stable/c/9c894159c5b8adc84…
https://git.kernel.org/stable/c/02c903fc6fc7e16c5…
https://git.kernel.org/stable/c/7a64521802997257b…
https://git.kernel.org/stable/c/b4af31b898a948e29…
https://git.kernel.org/stable/c/1b1937eb08f51319b…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 499f377f49f085ee4aa214c738e948e88626f39b , < f41ae7e6664f3c4361129728f2c4d5f3ed995251 (git) Affected: 499f377f49f085ee4aa214c738e948e88626f39b , < 210af872eafa0cf572a84cb303c0f9d2914c1226 (git) Affected: 499f377f49f085ee4aa214c738e948e88626f39b , < 3d8fa4b828a86b33c60858e58aaab6df273ede05 (git) Affected: 499f377f49f085ee4aa214c738e948e88626f39b , < 9c894159c5b8adc84072e3af0e55b0473a69564e (git) Affected: 499f377f49f085ee4aa214c738e948e88626f39b , < 02c903fc6fc7e16c5d1f22d18784f1208acf43e3 (git) Affected: 499f377f49f085ee4aa214c738e948e88626f39b , < 7a64521802997257b144e6edfb4e278dbeb972dd (git) Affected: 499f377f49f085ee4aa214c738e948e88626f39b , < b4af31b898a948e29861cb0bae734058f9a49d9b (git) Affected: 499f377f49f085ee4aa214c738e948e88626f39b , < 1b1937eb08f51319bf71575484cde2b8c517aedc (git)
Linux	Linux	Affected: 4.3 Unaffected: 0 , < 4.3 (semver) Unaffected: 5.10.261 , ≤ 5.10.* (semver) Unaffected: 5.15.212 , ≤ 5.15.* (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.96 , ≤ 6.12.* (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/extent-tree.c"
          ],
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          "vendor": "Linux",
          "versions": [
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          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.3"
            },
            {
              "lessThan": "4.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                },
                {
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                },
                {
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.96",
                  "versionStartIncluding": "4.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.39",
                  "versionStartIncluding": "4.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.4",
                  "versionStartIncluding": "4.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2-rc1",
                  "versionStartIncluding": "4.3",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: do not trim a device which is not writeable\n\n[BUG]\nThere is a bug report that btrfs/242 can randomly fail with the\nfollowing NULL pointer dereference:\n\n  run fstests btrfs/242 at 2026-06-01 10:25:08\n  BTRFS: device fsid d4d7f234-487c-4787-88e4-47a8b68c9874 devid 1 transid 9 /dev/sdc (8:32) scanned by mount (122609)\n  BTRFS info (device sdc): first mount of filesystem d4d7f234-487c-4787-88e4-47a8b68c9874\n  BTRFS info (device sdc): using crc32c checksum algorithm\n  BTRFS warning (device sdc): devid 2 uuid fbe72d72-3272-482d-80fb-ab88ed398192 is missing\n  BTRFS warning (device sdc): devid 2 uuid fbe72d72-3272-482d-80fb-ab88ed398192 is missing\n  BTRFS info (device sdc): allowing degraded mounts\n  BTRFS info (device sdc): turning on async discard\n  BTRFS info (device sdc): enabling free space tree\n  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018\n  user pgtable: 4k pages, 48-bit VAs, pgdp=000000013fd6b000\n  CPU: 4 UID: 0 PID: 122625 Comm: fstrim Not tainted 7.0.10-2-default #1 PREEMPT(full) openSUSE Tumbleweed e9a5f6b24978fba3bf015a992f865837fdfff3dd\n  Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20250812-19.fc42 08/12/2025\n  pstate: 01400005 (nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)\n  pc : btrfs_trim_fs+0x34c/0xa00 [btrfs]\n  lr : btrfs_trim_fs+0x1f0/0xa00 [btrfs]\n  Call trace:\n   btrfs_trim_fs+0x34c/0xa00 [btrfs f02c1d570ceea621c69d302ba75dd61868083840] (P)\n   btrfs_ioctl_fitrim+0xe8/0x178 [btrfs f02c1d570ceea621c69d302ba75dd61868083840]\n   btrfs_ioctl+0xdd4/0x2bd8 [btrfs f02c1d570ceea621c69d302ba75dd61868083840]\n   __arm64_sys_ioctl+0xac/0x108\n   invoke_syscall.constprop.0+0x5c/0xd0\n   el0_svc_common.constprop.0+0x40/0xf0\n   do_el0_svc+0x24/0x40\n   el0_svc+0x40/0x1d0\n   el0t_64_sync_handler+0xa0/0xe8\n   el0t_64_sync+0x1b0/0x1b8\n  Code: 17ffff83 f94017e0 f9002be0 f9402ea0 (f9400c00)\n  ---[ end trace 0000000000000000  ]---\n\nAlso the reporter is very kind to test the following ASSERT() added to\nbtrfs_trim_free_extents_throttle():\n\n\tASSERT(device-\u003ebdev,\n\t       \"devid=%llu path=%s dev_state=0x%lx\\n\",\n\t       device-\u003edevid, btrfs_dev_name(device), device-\u003edev_state);\n\nAnd it shows the following output:\n\n  assertion failed: device-\u003ebdev, in extent-tree.c:6630 (devid=2 path=/dev/sdd dev_state=0x82)\n\nWhich means the device-\u003ebdev is NULL, and the dev_state is\nBTRFS_DEV_STATE_IN_FS_METADATA | BTRFS_DEV_STATE_ITEM_FOUND, without\nBTRFS_DEV_STATE_WRITEABLE flag set.\n\n[CAUSE]\nThe pc points to the following call chain:\n\n  btrfs_trim_fs()\n  |- btrfs_trim_free_extents()\n     |- btrfs_trim_free_extents_throttle()\n        |- bdev_max_discard_sectors(device-\u003ebdev)\n\nSo the NULL pointer dereference is caused by device-\u003ebdev being NULL.\n\nThis looks impossible by a quick glance, as just before calling\nbtrfs_trim_free_extents_throttle(), we have skipped any device that has\nBTRFS_DEV_STATE_MISSING flag set.\n\nHowever in this particular case, there is a window where the missing\ndevice is later re-scanned, causing btrfs to remove the\nBTRFS_DEV_STATE_MISSING flag:\n\n  btrfs_control_ioctl()\n  |- btrfs_scan_one_device()\n     |- device_list_add()\n        |- rcu_assign_pointer(device-\u003ename, name);\n        |  This updates the missing device\u0027s path to the new good path.\n        |\n        |- clear_bit(BTRFS_DEV_STATE_MISSING, \u0026device-\u003edev_state)\n           This removes the BTRFS_DEV_STATE_MISSING flag.\n\nThis allows the missing device to re-appear and clear the\nBTRFS_DEV_STATE_MISSING flag.  However the device still does not have\nthe BTRFS_DEV_STATE_WRITEABLE flag set, nor is its bdev pointer updated.\n\nThe bdev pointer remains NULL, triggering the crash later.\n\n[FIX]\nThis is a big de-synchronization between BTRFS_DEV_STATE_MISSING and\ndevice-\u003ebdev pointer, and shows a gap in btrfs\u0027s re-appearing-device\nhandling.\n\nThe proper handling of re-appearing device will need quite some extra\nwork, which is out of the context of this small\n---truncated---"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-06T07:13:49.700Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f41ae7e6664f3c4361129728f2c4d5f3ed995251"
        },
        {
          "url": "https://git.kernel.org/stable/c/210af872eafa0cf572a84cb303c0f9d2914c1226"
        },
        {
          "url": "https://git.kernel.org/stable/c/3d8fa4b828a86b33c60858e58aaab6df273ede05"
        },
        {
          "url": "https://git.kernel.org/stable/c/9c894159c5b8adc84072e3af0e55b0473a69564e"
        },
        {
          "url": "https://git.kernel.org/stable/c/02c903fc6fc7e16c5d1f22d18784f1208acf43e3"
        },
        {
          "url": "https://git.kernel.org/stable/c/7a64521802997257b144e6edfb4e278dbeb972dd"
        },
        {
          "url": "https://git.kernel.org/stable/c/b4af31b898a948e29861cb0bae734058f9a49d9b"
        },
        {
          "url": "https://git.kernel.org/stable/c/1b1937eb08f51319bf71575484cde2b8c517aedc"
        }
      ],
      "title": "btrfs: do not trim a device which is not writeable",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64593",
    "datePublished": "2026-08-06T07:13:49.700Z",
    "dateReserved": "2026-07-19T15:36:31.799Z",
    "dateUpdated": "2026-08-06T07:13:49.700Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

GHSA-2HC3-VPVV-MWV3

CVE-2026-64593 (GCVE-0-2026-64593)

Tags

Sightings

Nomenclature