{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nriscv: Flush current cpu icache before other cpus\n\nOn SiFive Unmatched, I recently fell onto the following BUG when booting:\n\n[    0.000000] ftrace: allocating 36610 entries in 144 pages\n[    0.000000] Oops - illegal instruction [#1]\n[    0.000000] Modules linked in:\n[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.1+ #5\n[    0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT)\n[    0.000000] epc : riscv_cpuid_to_hartid_mask+0x6/0xae\n[    0.000000]  ra : __sbi_rfence_v02+0xc8/0x10a\n[    0.000000] epc : ffffffff80007240 ra : ffffffff80009964 sp : ffffffff81803e10\n[    0.000000]  gp : ffffffff81a1ea70 tp : ffffffff8180f500 t0 : ffffffe07fe30000\n[    0.000000]  t1 : 0000000000000004 t2 : 0000000000000000 s0 : ffffffff81803e60\n[    0.000000]  s1 : 0000000000000000 a0 : ffffffff81a22238 a1 : ffffffff81803e10\n[    0.000000]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000\n[    0.000000]  a5 : 0000000000000000 a6 : ffffffff8000989c a7 : 0000000052464e43\n[    0.000000]  s2 : ffffffff81a220c8 s3 : 0000000000000000 s4 : 0000000000000000\n[    0.000000]  s5 : 0000000000000000 s6 : 0000000200000100 s7 : 0000000000000001\n[    0.000000]  s8 : ffffffe07fe04040 s9 : ffffffff81a22c80 s10: 0000000000001000\n[    0.000000]  s11: 0000000000000004 t3 : 0000000000000001 t4 : 0000000000000008\n[    0.000000]  t5 : ffffffcf04000808 t6 : ffffffe3ffddf188\n[    0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000002\n[    0.000000] [<ffffffff80007240>] riscv_cpuid_to_hartid_mask+0x6/0xae\n[    0.000000] [<ffffffff80009474>] sbi_remote_fence_i+0x1e/0x26\n[    0.000000] [<ffffffff8000b8f4>] flush_icache_all+0x12/0x1a\n[    0.000000] [<ffffffff8000666c>] patch_text_nosync+0x26/0x32\n[    0.000000] [<ffffffff8000884e>] ftrace_init_nop+0x52/0x8c\n[    0.000000] [<ffffffff800f051e>] ftrace_process_locs.isra.0+0x29c/0x360\n[    0.000000] [<ffffffff80a0e3c6>] ftrace_init+0x80/0x130\n[    0.000000] [<ffffffff80a00f8c>] start_kernel+0x5c4/0x8f6\n[    0.000000] ---[ end trace f67eb9af4d8d492b ]---\n[    0.000000] Kernel panic - not syncing: Attempted to kill the idle task!\n[    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---\n\nWhile ftrace is looping over a list of addresses to patch, it always failed\nwhen patching the same function: riscv_cpuid_to_hartid_mask. Looking at the\nbacktrace, the illegal instruction is encountered in this same function.\nHowever, patch_text_nosync, after patching the instructions, calls\nflush_icache_range. But looking at what happens in this function:\n\nflush_icache_range -> flush_icache_all\n                   -> sbi_remote_fence_i\n                   -> __sbi_rfence_v02\n                   -> riscv_cpuid_to_hartid_mask\n\nThe icache and dcache of the current cpu are never synchronized between the\npatching of riscv_cpuid_to_hartid_mask and calling this same function.\n\nSo fix this by flushing the current cpu's icache before asking for the other\ncpus to do the same."
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "arch/riscv/mm/cacheflush.c"
               ],
               "versions": [
                  {
                     "version": "fab957c11efe",
                     "lessThan": "427faa29e06f",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "fab957c11efe",
                     "lessThan": "f1c7aa87c423",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "fab957c11efe",
                     "lessThan": "bb8958d5dc79",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "arch/riscv/mm/cacheflush.c"
               ],
               "versions": [
                  {
                     "version": "4.15",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "4.15",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.10.73",
                     "lessThanOrEqual": "5.10.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.14.12",
                     "lessThanOrEqual": "5.14.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.15",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/427faa29e06f0709476ea1bd59758f997ec8b64e"
            },
            {
               "url": "https://git.kernel.org/stable/c/f1c7aa87c423e765e3862349c2f095fdfccdd9b3"
            },
            {
               "url": "https://git.kernel.org/stable/c/bb8958d5dc79acbd071397abb57b8756375fe1ce"
            }
         ],
         "title": "riscv: Flush current cpu icache before other cpus",
         "x_generator": {
            "engine": "bippy-a5840b7849dd"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2021-47414",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}