{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2024-27031",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2024-27031"
  ],
  "published": "2024-05-01T12:57:40Z",
  "summary": "NFS: Fix nfs_netfs_issue_read() xarray locking for writeback interrupt",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFS: Fix nfs_netfs_issue_read() xarray locking for writeback interrupt\n\nThe loop inside nfs_netfs_issue_read() currently does not disable\ninterrupts while iterating through pages in the xarray to submit\nfor NFS read.  This is not safe though since after taking xa_lock,\nanother page in the mapping could be processed for writeback inside\nan interrupt, and deadlock can occur.  The fix is simple and clean\nif we use xa_for_each_range(), which handles the iteration with RCU\nwhile reducing code complexity.\n\nThe problem is easily reproduced with the following test:\n mount -o vers=3,fsc 127.0.0.1:/export /mnt/nfs\n dd if=/dev/zero of=/mnt/nfs/file1.bin bs=4096 count=1\n echo 3 > /proc/sys/vm/drop_caches\n dd if=/mnt/nfs/file1.bin of=/dev/null\n umount /mnt/nfs\n\nOn the console with a lockdep-enabled kernel a message similar to\nthe following will be seen:\n\n ================================\n WARNING: inconsistent lock state\n 6.7.0-lockdbg+ #10 Not tainted\n --------------------------------\n inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.\n test5/1708 [HC0[0]:SC0[0]:HE1:SE1] takes:\n ffff888127baa598 (&xa->xa_lock#4){+.?.}-{3:3}, at:\nnfs_netfs_issue_read+0x1b2/0x4b0 [nfs]\n {IN-SOFTIRQ-W} state was registered at:\n   lock_acquire+0x144/0x380\n   _raw_spin_lock_irqsave+0x4e/0xa0\n   __folio_end_writeback+0x17e/0x5c0\n   folio_end_writeback+0x93/0x1b0\n   iomap_finish_ioend+0xeb/0x6a0\n   blk_update_request+0x204/0x7f0\n   blk_mq_end_request+0x30/0x1c0\n   blk_complete_reqs+0x7e/0xa0\n   __do_softirq+0x113/0x544\n   __irq_exit_rcu+0xfe/0x120\n   irq_exit_rcu+0xe/0x20\n   sysvec_call_function_single+0x6f/0x90\n   asm_sysvec_call_function_single+0x1a/0x20\n   pv_native_safe_halt+0xf/0x20\n   default_idle+0x9/0x20\n   default_idle_call+0x67/0xa0\n   do_idle+0x2b5/0x300\n   cpu_startup_entry+0x34/0x40\n   start_secondary+0x19d/0x1c0\n   secondary_startup_64_no_verify+0x18f/0x19b\n irq event stamp: 176891\n hardirqs last  enabled at (176891): [<ffffffffa67a0be4>]\n_raw_spin_unlock_irqrestore+0x44/0x60\n hardirqs last disabled at (176890): [<ffffffffa67a0899>]\n_raw_spin_lock_irqsave+0x79/0xa0\n softirqs last  enabled at (176646): [<ffffffffa515d91e>]\n__irq_exit_rcu+0xfe/0x120\n softirqs last disabled at (176633): [<ffffffffa515d91e>]\n__irq_exit_rcu+0xfe/0x120\n\n other info that might help us debug this:\n  Possible unsafe locking scenario:\n\n        CPU0\n        ----\n   lock(&xa->xa_lock#4);\n   <Interrupt>\n     lock(&xa->xa_lock#4);\n\n  *** DEADLOCK ***\n\n 2 locks held by test5/1708:\n  #0: ffff888127baa498 (&sb->s_type->i_mutex_key#22){++++}-{4:4}, at:\n      nfs_start_io_read+0x28/0x90 [nfs]\n  #1: ffff888127baa650 (mapping.invalidate_lock#3){.+.+}-{4:4}, at:\n      page_cache_ra_unbounded+0xa4/0x280\n\n stack backtrace:\n CPU: 6 PID: 1708 Comm: test5 Kdump: loaded Not tainted 6.7.0-lockdbg+\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39\n04/01/2014\n Call Trace:\n  dump_stack_lvl+0x5b/0x90\n  mark_lock+0xb3f/0xd20\n  __lock_acquire+0x77b/0x3360\n  _raw_spin_lock+0x34/0x80\n  nfs_netfs_issue_read+0x1b2/0x4b0 [nfs]\n  netfs_begin_read+0x77f/0x980 [netfs]\n  nfs_netfs_readahead+0x45/0x60 [nfs]\n  nfs_readahead+0x323/0x5a0 [nfs]\n  read_pages+0xf3/0x5c0\n  page_cache_ra_unbounded+0x1c8/0x280\n  filemap_get_pages+0x38c/0xae0\n  filemap_read+0x206/0x5e0\n  nfs_file_read+0xb7/0x140 [nfs]\n  vfs_read+0x2a9/0x460\n  ksys_read+0xb7/0x140",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.6.20-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.6.20+rpt-rpi-2712",
            "binary_version": "1:6.6.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.20+rpt-rpi-v6",
            "binary_version": "1:6.6.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.20+rpt-rpi-v7",
            "binary_version": "1:6.6.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.20+rpt-rpi-v7l",
            "binary_version": "1:6.6.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.20+rpt-rpi-v8",
            "binary_version": "1:6.6.20-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.6.20-1+rpt1": {
            "linux_commit": "6f16847710cc0502450788b9f12f0a14d3429668",
            "upstream_version": "6.6.20",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.6.23"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2024-27031"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ad27382f8495f8ef6d2c66c413d756bfd13c0598"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8df1678c021ffeb20ef8a203bd9413f3ed9b0e9a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8a2e5977cecd3cde6a0e3e86b7b914d00240e5dc"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/fd5860ab6341506004219b080aea40213b299d2e"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-12T04:54:46Z"
  }
}