<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/144847>144847</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Linux kernel version is unknown
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          jakesteele
      </td>
    </tr>
</table>

<pre>
    OS: Linux Cachy 6.15.2-2 
LLVM Version: 20.7.1
Perf Version: `perf version 6.15-2`

Command I am running:
```
~/llvm-project/build/bin tags/llvmorg-20.1.7^0 jacob@Server
❯ sudo ./perf2bolt -p perf.data -o bolt.fdata /usr/src/debug/linux-cachyos/vmlinux
```

```
PERF2BOLT: Starting data aggregation job for perf.data
PERF2BOLT: spawning perf job to read branch events
PERF2BOLT: spawning perf job to read mem events
PERF2BOLT: spawning perf job to read process events
PERF2BOLT: spawning perf job to read task events
BOLT-INFO: Target architecture: x86_64
BOLT-INFO: BOLT version: 6146a88f60492b520a36f8f8f3231e15f3cc6082
BOLT-INFO: Linux kernel binary detected
BOLT-INFO: first alloc address is 0xffffffff81000000
BOLT-INFO: static input executable detected
BOLT-INFO: enabling lite mode
BOLT-WARNING: ignoring symbol __end_rodata at 0xffffffff834c6000, which lies outside .BTF_ids
BOLT-WARNING: ignoring symbol __end_rodata_hpage_align at 0xffffffff83600000, which lies outside .BTF_ids
BOLT-WARNING: ignoring symbol __end_rodata_aligned at 0xffffffff83600000, which lies outside .BTF_ids
BOLT-WARNING: split function detected on input : task_rq_lock.cold
BOLT-ERROR: symbol seen in the middle of the function srso_untrain_ret/1(*2). Skipping.
BOLT-ERROR: symbol seen in the middle of the function retbleed_untrain_ret/1(*2). Skipping.
BOLT-INFO: pre-processing profile using perf data aggregator
BOLT-INFO: binary build-id is:     873e93cae96bc10932d87f1da57dcee21256f08d
PERF2BOLT: spawning perf job to read buildid list
PERF2BOLT-WARNING: build-id matched a different file name
PERF2BOLT: waiting for perf task events collection to finish...
PERF2BOLT: parsing perf-script task events output
PERF2BOLT: input binary is associated with 0 PID(s)
PERF2BOLT: waiting for perf events collection to finish...
PERF2BOLT: parse branch events...
PERF2BOLT: read 264338 samples and 6877582 LBR entries
PERF2BOLT: 0 samples (0.0%) were ignored
PERF2BOLT: traces mismatching disassembled function contents: 6923 (0.1%)
PERF2BOLT: out of range traces involving unknown regions: 630520 (9.5%)
PERF2BOLT: waiting for perf mem events collection to finish...
BOLT-ERROR: while running linux-kernel-rewriter in pre-CFG state: Linux kernel version is unknown
```

However I clearly see it:
```
❯ strings /usr/src/debug/linux-cachyos/vmlinux | grep 'Linux version'
Linux version 6.15.2-2-cachyos (linux-cachyos@cachyos) (clang version 20.1.6, LLD 20.1.6) # SMP Thu, 19 Jun 2025 03:26:16 +0000
Linux version 6.15.2-2-cachyos (linux-cachyos@cachyos) (clang version 20.1.6, LLD 20.1.6) #1 SMP Thu, 19 Jun 2025 03:26:16 +0000
```

I believe it's failing to parse the string for some reason. 
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJy8V0tv4zgS_jX0pWCBot4HH5x0ezaLTHcjacweDYosyexQpJak7M5lf_uC8iOJM7uzwQ5GMGCwWFVfqd7i3qveIK5IcUOKTws-hZ11qx_8CX1A1LhorXxefX0k2RrulZl-wi0Xu2cok7RI2JIBoev7-99-hd_QeWVN5GM0qZKU0PU3dN3rC1LSMZL2R9KsZMlISQldE7q-tcPAjYQ74AO4yRhlepLFm8hy_NH1vwjbaL0flqOzP1AEwjbtpLSM_8pA4L0_cVjXLxlN0qQixWcKP7iwLcnpI7o9uqj1MyPNJ7LegJ-khYSwTTSPtVYHWI4QD4nkgcPSQiQm3XwibDN5R9jGO0HYRmI79REyumcpontsNGE_zJQr86-O3z4_bNjN1_vv0T-PgbugTA8zDO97hz0P0VM_bAuddS8mXYv6kR-iv2aOmT1YcMgltI4bsQPcown-fxcbcPiwzOisQO8_LBe4f3oRivzLuy-br1HoO3c9BuBO7FRAESaHkfyzLrdlfs0cD-fkiucyzUte111J84a1BaM8K7u6q7uMZSmmRZcJUdKaXes5JvoTOoMaWmW4ewaJER7lNW-nnA_AtbYCuJQuvr_yQH92p6dO6fxcC_rAgxKgzDgFwJ8opsBbjf8RCA1vdXSfVgFhsBLPHP9YP3y5-_JLZFK9sS4y-eehtRq2WzRy6-wxocJrs7JclNEsdguHnRI70Ao92Cl4JRGSm--brZL-gxjb3ch73HKtenONVx7d8OfizUgo_ywsP2oVoJuMmMvuHAuw5hSoyBTTdev-udVWPCXC6kuoPj88fH2Y1Rwt9YhRDsIOYVBSagTbzacLgnfebicTHFdm6zB2s5SwmrA1I6xJ4PFJjaMyffJ_YDgMrUaUH8I5p93ocHmq67l2ne2URpj8pZLfNCvrrhWc6mfu0UslQflIjU9dZdhkgmNTtiKlTcZkXXWp5EUlBSJLWVF2tJYf6HURREnQyofXUq9DfDFk4EHsYuqAVF2HDk2A-d0MH_Aa88DV3JnPTfh1zwJhtcajr4OFThnld0mSXOsYubt4bemFU2N4o8ZOYZzCtdQx705eVB6491YoHrPyoMIOKHy7-0RY7Qlr_tDqjxuMbwfI73DNnmdlnmU1eD6MGj3EMV7WVVXUDO5vHgBNcArfjQR6ESCspgklrCCsgQM6PJY9vgt-cFygh0H5OX7ztFSee49Dq1G-ZL2wJswTJQ6ChmVHiPQIca3VTiGWjeOmxzOEMnur9xFgMk_GHmIh9cqao8aMFoxGnU1S_L7Od85_Gan_JQBvi_ywiwl52oXguGEc59LS4cGpgC4WfyzS280v80zBdxPsvG4pf36T9zvJ3-wB9-jgDoRG7vRzbCygwvv969XWFGJb9h_ch4BUt9A7HIGw6mjneWSzKm6Tr0mXPfOsJ3r8reKcXiCaeCs0N_1Fft7_yjgI7u8_XU6RMYPHX7_B990UL9MG_j5FblYAzUi2ZiXJ1mkJhN2chvdfZlf6QcOuInkHLWqF-zl6rPLQcTXvDcGeCjoOh2Ps5tz0dsBYxN6aBBZylckma_gCV2lV0Cwt8jxd7FaC06rrKKurtsCiq6u666pKoiyxYGWRL9QqGknLtKFlntM0SXlX0aZjTMqua_KS5BQHrnQSd_PEun6hvJ9wleZ5nVcLzVvUfv4QYczgAeZbwlj8LnGreeVvpz46NrZ3_6ImqKBx9Qcpv5icXu1CGGP5ErYhbNOrsJvaRNjh9MHw_stitiEm78nI_Yr9OwAA__9ogTML">