{
  "cveId": "CVE-2021-47414",
  "url": "https://patchblox.com/security/cve/CVE-2021-47414",
  "summary": "CVE-2021-47414 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47414, released May 21, 2024. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  riscv: Flush current cpu icache before other cpu...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  riscv: Flush current cpu icache before other cpus  On SiFive Unmatched, I recently fell onto the following BUG when booting:  [    0.000000] ftrace: allocating 36610 entries in 144 pages [    0.000000] Oops - illegal instruction [#1] [    0.000000] Modules linked in: [    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.1\u002B #5 [    0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT) [    0.000000] epc : riscv_cpuid_to_hartid_mask\u002B0x6/0xae [    0.000000]  ra : __sbi_rfence_v02\u002B0xc8/0x10a [    0.000000] epc : ffffffff80007240 ra : ffffffff80009964 sp : ffffffff81803e10 [    0.000000]  gp : ffffffff81a1ea70 tp : ffffffff8180f500 t0 : ffffffe07fe30000 [    0.000000]  t1 : 0000000000000004 t2 : 0000000000000000 s0 : ffffffff81803e60 [    0.000000]  s1 : 0000000000000000 a0 : ffffffff81a22238 a1 : ffffffff81803e10 [    0.000000]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000 [    0.000000]  a5 : 0000000000000000 a6 : ffffffff8000989c a7 : 0000000052464e43 [    0.000000]  s2 : ffffffff81a220c8 s3 : 0000000000000000 s4 : 0000000000000000 [    0.000000]  s5 : 0000000000000000 s6 : 0000000200000100 s7 : 0000000000000001 [    0.000000]  s8 : ffffffe07fe04040 s9 : ffffffff81a22c80 s10: 0000000000001000 [    0.000000]  s11: 0000000000000004 t3 : 0000000000000001 t4 : 0000000000000008 [    0.000000]  t5 : ffffffcf04000808 t6 : ffffffe3ffddf188 [    0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000002 [    0.000000] [\u003Cffffffff80007240\u003E] riscv_cpuid_to_hartid_mask\u002B0x6/0xae [    0.000000] [\u003Cffffffff80009474\u003E] sbi_remote_fence_i\u002B0x1e/0x26 [    0.000000] [\u003Cffffffff8000b8f4\u003E] flush_icache_all\u002B0x12/0x1a [    0.000000] [\u003Cffffffff8000666c\u003E] patch_text_nosync\u002B0x26/0x32 [    0.000000] [\u003Cffffffff8000884e\u003E] ftrace_init_nop\u002B0x52/0x8c [    0.000000] [\u003Cffffffff800f051e\u003E] ftrace_process_locs.isra.0\u002B0x29c/0x360 [    0.000000] [\u003Cffffffff80a0e3c6\u003E] ftrace_init\u002B0x80/0x130 [    0.000000] [\u003Cffffffff80a00f8c\u003E] start_kernel\u002B0x5c4/0x8f6 [    0.000000] ---[ end trace f67eb9af4d8d492b ]--- [    0.000000] Kernel panic - not syncing: Attempted to kill the idle task! [    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---  While ftrace is looping over a list of addresses to patch, it always failed when patching the same function: riscv_cpuid_to_hartid_mask. Looking at the backtrace, the illegal instruction is encountered in this same function. However, patch_text_nosync, after patching the instructions, calls flush_icache_range. But looking at what happens in this function:  flush_icache_range -\u003E flush_icache_all                    -\u003E sbi_remote_fence_i                    -\u003E __sbi_rfence_v02                    -\u003E riscv_cpuid_to_hartid_mask  The icache and dcache of the current cpu are never synchronized between the patching of riscv_cpuid_to_hartid_mask and calling this same function.  So fix this by flushing the current cpu\u0027s icache before asking for the other cpus to do the same.",
  "published": "2024-05-21T15:15:26Z",
  "severity": "medium",
  "cvss": 5.5,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00222,
  "epssPercentile": 0.12925,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "5.14.12-1",
      "fix": "DEBIAN-CVE-2021-47414",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47414",
      "released": "2024-05-21T15:15:26Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "5.14.12-1",
      "fix": "DEBIAN-CVE-2021-47414",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47414",
      "released": "2024-05-21T15:15:26Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "5.14.12-1",
      "fix": "DEBIAN-CVE-2021-47414",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47414",
      "released": "2024-05-21T15:15:26Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}