Messages in this thread | | | From | Ard Biesheuvel <> | Date | Wed, 4 Oct 2017 18:44:01 +0100 | Subject | Re: [PATCH] scripts/kallsyms: Ignore symbol type 'n' |
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On 4 October 2017 at 17:54, Guenter Roeck <linux@roeck-us.net> wrote: > gcc on aarch64 may emit synbols of type 'n' if the kernel is built with > '-frecord-gcc-switches'. In most cases, those symbols are reported > with nm as > 000000000000000e n $d > and with objdump as > 0000000000000000 l d .GCC.command.line 0000000000000000 .GCC.command.line > 000000000000000e l .GCC.command.line 0000000000000000 $d > > Those symbols are detected in is_arm_mapping_symbol() and ignored. However, > if "--prefix-symbols=<prefix>" is configured as well, the situation is > different. For example, in efi/libstub, arm64 images are built with > '--prefix-alloc-sections=.init --prefix-symbols=__efistub_'. > In combination with '-frecord-gcc-switches', the symbols are now reported > by nm as: > 000000000000000e n __efistub_$d > and by objdump as: > 0000000000000000 l d .GCC.command.line 0000000000000000 .GCC.command.line > 000000000000000e l .GCC.command.line 0000000000000000 __efistub_$d > > Those symbols are no longer ignored and included in the base address > calculation. This results in a base address of 000000000000000e, which > in turn causes kallsyms to abort with > kallsyms failure: > relative symbol value 0xffffff900800a000 out of range in relative mode > > The problem is seen in little endian arm64 builds with CONFIG_EFI enabled > and with '-frecord-gcc-switches' set in KCFLAGS. > > Explicitly ignore symbols of type 'n' since those are clearly debug > symbols. > > Cc: Josh Poimboeuf <jpoimboe@redhat.com> > Signed-off-by: Guenter Roeck <linux@roeck-us.net> > --- > scripts/kallsyms.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c > index 5d554419170b..9ee9bf7fd1a2 100644 > --- a/scripts/kallsyms.c > +++ b/scripts/kallsyms.c > @@ -158,7 +158,7 @@ static int read_symbol(FILE *in, struct sym_entry *s) > else if (str[0] == '$') > return -1; > /* exclude debugging symbols */ > - else if (stype == 'N') > + else if (stype == 'N' || stype == 'n') > return -1; > > /* include the type field in the symbol name, so that it gets
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
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