CVE-2026-43299 (GCVE-0-2026-43299)

Vulnerability from cvelistv5 – Published: 2026-05-08 13:11 – Updated: 2026-05-11 22:21
VLAI
Title
btrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure()
Summary
In the Linux kernel, the following vulnerability has been resolved: btrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure() [BUG] There is a bug report that when btrfs hits ENOSPC error in a critical path, btrfs flips RO (this part is expected, although the ENOSPC bug still needs to be addressed). The problem is after the RO flip, if there is a read repair pending, we can hit the ASSERT() inside btrfs_repair_io_failure() like the following: BTRFS info (device vdc): relocating block group 30408704 flags metadata|raid1 ------------[ cut here ]------------ BTRFS: Transaction aborted (error -28) WARNING: fs/btrfs/extent-tree.c:3235 at __btrfs_free_extent.isra.0+0x453/0xfd0, CPU#1: btrfs/383844 Modules linked in: kvm_intel kvm irqbypass [...] ---[ end trace 0000000000000000 ]--- BTRFS info (device vdc state EA): 2 enospc errors during balance BTRFS info (device vdc state EA): balance: ended with status: -30 BTRFS error (device vdc state EA): parent transid verify failed on logical 30556160 mirror 2 wanted 8 found 6 BTRFS error (device vdc state EA): bdev /dev/nvme0n1 errs: wr 0, rd 0, flush 0, corrupt 10, gen 0 [...] assertion failed: !(fs_info->sb->s_flags & SB_RDONLY) :: 0, in fs/btrfs/bio.c:938 ------------[ cut here ]------------ assertion failed: !(fs_info->sb->s_flags & SB_RDONLY) :: 0, in fs/btrfs/bio.c:938 kernel BUG at fs/btrfs/bio.c:938! Oops: invalid opcode: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 868 Comm: kworker/u8:13 Tainted: G W N 6.19.0-rc6+ #4788 PREEMPT(full) Tainted: [W]=WARN, [N]=TEST Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 Workqueue: btrfs-endio simple_end_io_work RIP: 0010:btrfs_repair_io_failure.cold+0xb2/0x120 RSP: 0000:ffffc90001d2bcf0 EFLAGS: 00010246 RAX: 0000000000000051 RBX: 0000000000001000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8305cf42 RDI: 00000000ffffffff RBP: 0000000000000002 R08: 00000000fffeffff R09: ffffffff837fa988 R10: ffffffff8327a9e0 R11: 6f69747265737361 R12: ffff88813018d310 R13: ffff888168b8a000 R14: ffffc90001d2bd90 R15: ffff88810a169000 FS: 0000000000000000(0000) GS:ffff8885e752c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 ------------[ cut here ]------------ [CAUSE] The cause of -ENOSPC error during the test case btrfs/124 is still unknown, although it's known that we still have cases where metadata can be over-committed but can not be fulfilled correctly, thus if we hit such ENOSPC error inside a critical path, we have no choice but abort the current transaction. This will mark the fs read-only. The problem is inside the btrfs_repair_io_failure() path that we require the fs not to be mount read-only. This is normally fine, but if we are doing a read-repair meanwhile the fs flips RO due to a critical error, we can enter btrfs_repair_io_failure() with super block set to read-only, thus triggering the above crash. [FIX] Just replace the ASSERT() with a proper return if the fs is already read-only.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 908960c6c0fb3b3ce3971dc0ca47b581d256b968 , < f6df18c001e3dcebc08482d0adeacd0cfea08593 (git)
Affected: 908960c6c0fb3b3ce3971dc0ca47b581d256b968 , < 8ceaad6cd6e7fa5f73b0b2796a2e85d75d37e9f3 (git)
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Linux Linux Affected: 3.13
Unaffected: 0 , < 3.13 (semver)
Unaffected: 6.19.6 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/bio.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "f6df18c001e3dcebc08482d0adeacd0cfea08593",
              "status": "affected",
              "version": "908960c6c0fb3b3ce3971dc0ca47b581d256b968",
              "versionType": "git"
            },
            {
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          "vendor": "Linux",
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              "version": "3.13"
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            },
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              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
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      "cpeApplicability": [
        {
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            {
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.6",
                  "versionStartIncluding": "3.13",
                  "vulnerable": true
                },
                {
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                  "versionStartIncluding": "3.13",
                  "vulnerable": true
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure()\n\n[BUG]\nThere is a bug report that when btrfs hits ENOSPC error in a critical\npath, btrfs flips RO (this part is expected, although the ENOSPC bug\nstill needs to be addressed).\n\nThe problem is after the RO flip, if there is a read repair pending, we\ncan hit the ASSERT() inside btrfs_repair_io_failure() like the following:\n\n  BTRFS info (device vdc): relocating block group 30408704 flags metadata|raid1\n  ------------[ cut here ]------------\n  BTRFS: Transaction aborted (error -28)\n  WARNING: fs/btrfs/extent-tree.c:3235 at __btrfs_free_extent.isra.0+0x453/0xfd0, CPU#1: btrfs/383844\n  Modules linked in: kvm_intel kvm irqbypass\n  [...]\n  ---[ end trace 0000000000000000 ]---\n  BTRFS info (device vdc state EA): 2 enospc errors during balance\n  BTRFS info (device vdc state EA): balance: ended with status: -30\n  BTRFS error (device vdc state EA): parent transid verify failed on logical 30556160 mirror 2 wanted 8 found 6\n  BTRFS error (device vdc state EA): bdev /dev/nvme0n1 errs: wr 0, rd 0, flush 0, corrupt 10, gen 0\n  [...]\n  assertion failed: !(fs_info-\u003esb-\u003es_flags \u0026 SB_RDONLY) :: 0, in fs/btrfs/bio.c:938\n  ------------[ cut here ]------------\n  assertion failed: !(fs_info-\u003esb-\u003es_flags \u0026 SB_RDONLY) :: 0, in fs/btrfs/bio.c:938\n  kernel BUG at fs/btrfs/bio.c:938!\n  Oops: invalid opcode: 0000 [#1] SMP NOPTI\n  CPU: 0 UID: 0 PID: 868 Comm: kworker/u8:13 Tainted: G        W        N  6.19.0-rc6+ #4788 PREEMPT(full)\n  Tainted: [W]=WARN, [N]=TEST\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014\n  Workqueue: btrfs-endio simple_end_io_work\n  RIP: 0010:btrfs_repair_io_failure.cold+0xb2/0x120\n  RSP: 0000:ffffc90001d2bcf0 EFLAGS: 00010246\n  RAX: 0000000000000051 RBX: 0000000000001000 RCX: 0000000000000000\n  RDX: 0000000000000000 RSI: ffffffff8305cf42 RDI: 00000000ffffffff\n  RBP: 0000000000000002 R08: 00000000fffeffff R09: ffffffff837fa988\n  R10: ffffffff8327a9e0 R11: 6f69747265737361 R12: ffff88813018d310\n  R13: ffff888168b8a000 R14: ffffc90001d2bd90 R15: ffff88810a169000\n  FS:  0000000000000000(0000) GS:ffff8885e752c000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  ------------[ cut here ]------------\n\n[CAUSE]\nThe cause of -ENOSPC error during the test case btrfs/124 is still\nunknown, although it\u0027s known that we still have cases where metadata can\nbe over-committed but can not be fulfilled correctly, thus if we hit\nsuch ENOSPC error inside a critical path, we have no choice but abort\nthe current transaction.\n\nThis will mark the fs read-only.\n\nThe problem is inside the btrfs_repair_io_failure() path that we require\nthe fs not to be mount read-only. This is normally fine, but if we are\ndoing a read-repair meanwhile the fs flips RO due to a critical error,\nwe can enter btrfs_repair_io_failure() with super block set to\nread-only, thus triggering the above crash.\n\n[FIX]\nJust replace the ASSERT() with a proper return if the fs is already\nread-only."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:21:52.285Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f6df18c001e3dcebc08482d0adeacd0cfea08593"
        },
        {
          "url": "https://git.kernel.org/stable/c/8ceaad6cd6e7fa5f73b0b2796a2e85d75d37e9f3"
        }
      ],
      "title": "btrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43299",
    "datePublished": "2026-05-08T13:11:20.872Z",
    "dateReserved": "2026-05-01T14:12:56.000Z",
    "dateUpdated": "2026-05-11T22:21:52.285Z",
    "state": "PUBLISHED"
  },
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  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-43299",
      "date": "2026-10-03",
      "epss": "0.00117",
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      "current_release_date": "2026-10-03T00:55:18Z",
      "cve": "CVE-2026-43299",
      "id": "CVE-2026-43299",
      "initial_release_date": "2026-05-12T03:31:06Z",
      "product_status:known_affected": "385",
      "product_status:known_not_affected": "4",
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      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-43299",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-43299.json",
      "version": "4"
    }
  }
}



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