Re: [Crash-utility] [PATCH] Fix warning about kernel version inconsistency during crash startup

On 2023/07/24 16:33, lijiang wrote: > On Mon, Jul 24, 2023 at 3:07 PM HAGIO KAZUHITO(萩尾 一仁) < k-hagio-ab(a)nec.com&gt; > wrote: > >> On 2023/07/24 15:51, lijiang wrote: >>> How about reading out the linux_banner string to a buffer with readmem()? >> >> No, this is a version check for the namelist (vmlinux). >> >> > Ah, you are right, Kazu. > >>> 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? >>>> >>>> >>> I tried the "__start_rodata" symbol, but it does not work. >> >> How did you try? There is no "__start_rodata" symbol? >> >> I mean something like this: >> >> --- a/kernel.c >> +++ b/kernel.c >> @@ -11893,8 +11893,13 @@ int get_linux_banner_from_vmlinux(char *buf, >> size_t size) >> { >> struct bfd_section *sect; >> long offset; >> + ulong start_rodata; >> >> - if (!kernel_symbol_exists(".rodata")) >> + if (kernel_symbol_exists(".rodata")) >> + start_rodata = symbol_value(".rodata"); >> + else if (kernel_symbol_exists("__start_rodata")) >> + start_rodata = symbol_value("__start_rodata"); >> + else >> return FALSE; >> >> sect = bfd_get_section_by_name(st->bfd, ".rodata"); >> > > The ".rodata" is a section, I mistakenly replaced the ".rodata" with the > symbol "__start_rodata" in a debug patch, so it does not work. :-) > > diff --git a/kernel.c b/kernel.c > index 546eed9..3c50fa4 100644 > --- a/kernel.c > +++ b/kernel.c > @@ -11894,7 +11894,7 @@ int get_linux_banner_from_vmlinux(char *buf, size_t > size) > struct bfd_section *sect; > long offset; > > - if (!kernel_symbol_exists(".rodata")) > + if (!kernel_symbol_exists("__start_rodata")) > return FALSE; > > sect = bfd_get_section_by_name(st->bfd, ".rodata"); > @@ -11907,7 +11907,7 @@ int get_linux_banner_from_vmlinux(char *buf, size_t > size) > * value in vmlinux file, but relative offset to linux_banner > * object in .rodata section is idential. > */ > - offset = symbol_value("linux_banner") - symbol_value(".rodata"); > + offset = symbol_value("linux_banner") - > symbol_value("__start_rodata"); > > if (!bfd_get_section_contents(st->bfd, > sect, > @@ -11916,5 +11916,6 @@ int get_linux_banner_from_vmlinux(char *buf, size_t > size) > size)) > return FALSE; > > + error(INFO, "%s\n", buf); > return TRUE; > > For now, the get_linux_banner_from_vmlinux() works again with the debug > patch. Good, thanks for the test. I will send a patch for this.