On 2023/07/24 10:17, HAGIO KAZUHITO(萩尾 一仁) wrote: > Hi Lianbo, > > Thank you for the fix. > > On 2023/07/21 13:36, Lianbo Jiang wrote: >> Currently, the symbol ".rodata" may not be found in some vmlinux, and >> the strings command will still be used to get the linux banner string, >> but this gets two strings as below: >> >> # strings /usr/lib/debug/usr/lib/modules/6.5.0-0.rc2.17.fc39.x86_64/vmlinux |grep "Linux version" >> Linux version 6.5.0-0.rc2.17.fc39.x86_64 (mockbuild@23a79bad375e4c2c8c60f2d40df7df49) (gcc (GCC) 13.1.1 20230614 (Red Hat 13.1.1-4), GNU ld version 2.40-9.fc39) # SMP PREEMPT_DYNAMIC >> Linux version 6.5.0-0.rc2.17.fc39.x86_64 (mockbuild@23a79bad375e4c2c8c60f2d40df7df49) (gcc (GCC) 13.1.1 20230614 (Red Hat 13.1.1-4), GNU ld version 2.40-9.fc39) #1 SMP PREEMPT_DYNAMIC Mon Jul 17 14:57:35 UTC 2023 >> >> In the verify_namelist(), the while-loop will only determine if the >> above first string(linux banner) matches and break the loop. But >> actually the above second string is correct one. Eventually, crash >> startup with the following warning: >> >> # ./crash -s /usr/lib/debug/usr/lib/modules/6.5.0-0.rc2.17.fc39.x86_64/vmlinux /var/crash/127.0.0.1-2023-07-20-20\:50\:50/vmcore >> WARNING: kernel version inconsistency between vmlinux and dumpfile >> >> # ./crash -s >> WARNING: kernel version inconsistency between vmlinux and live memory >> >> Let's always try to match the correct one, otherwise still prints a >> warning as before. >> >> Signed-off-by: Lianbo Jiang <lijiang@xxxxxxxxxx> >> --- >> kernel.c | 2 -- >> 1 file changed, 2 deletions(-) >> >> diff --git a/kernel.c b/kernel.c >> index 546eed95eebd..9801812387bd 100644 >> --- a/kernel.c >> +++ b/kernel.c >> @@ -1375,8 +1375,6 @@ verify_namelist() >> buffer3[i++] = *p1++; >> buffer3[i] = NULLCHAR; >> } >> - >> - break; >> } >> pclose(pipe); >> > > I think you are fixing the fallback routine and that's good, but it's > better to fix get_linux_banner_from_vmlinux() first if possible. It's > much faster. Isn't it possible? > > What do you see in "sections:" in "help -s"? And probably you can > determine the section where linux_banner is located, with the address of > linux_banner and KASLR offset. > > crash> help -s > ... > sections: > .text vma: ffffffff81000000 size: 14686984 > .rodata vma: ffffffff82000000 size: 5366231 > .pci_fixup vma: ffffffff8251e1e0 size: 14112 > ... > crash> sym linux_banner > ffffffffb5200a40 (D) linux_banner > crash> help -D | grep KERNELOFFSET > KERNELOFFSET=33200000 > > crash> eval ffffffffb5200a40 - 0x33200000 > hexadecimal: ffffffff82000a40 --> linux_banner is in ".rodata" If the vmlinux does not have only the ".rodata" symbol, is it possible to use "__start_rodata" symbol or something? i.e. is there no symbol that has the same address as .rodata section? crash> sym .rodata __start_rodata ffffffffb5200000 (d) .rodata ffffffffb5200000 (D) __start_rodata Thanks, Kazu > > > Thanks, > Kazu > -- > Crash-utility mailing list > Crash-utility@xxxxxxxxxx > https://listman.redhat.com/mailman/listinfo/crash-utility > Contribution Guidelines: https://github.com/crash-utility/crash/wiki -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/crash-utility Contribution Guidelines: https://github.com/crash-utility/crash/wiki
