Messages in this thread | | | Date | Thu, 24 Oct 2013 13:42:14 +0800 | Subject | Re: [RFC PATCH] kernel/kallsyms.c: only show legal kernel symbol | From | Ming Lei <> |
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On Thu, Oct 24, 2013 at 9:21 AM, Rusty Russell <rusty@rustcorp.com.au> wrote: > Ming Lei <tom.leiming@gmail.com> writes: >> Address of non-module kernel symbol should always be located >> from CONFIG_PAGE_OFFSET on, so only show these legal kernel >> symbols in /proc/kallsyms. >> >> On ARM, some symbols(see below) may drop in relocatable code, so >> perf can't parse kernel symbols any more from /proc/kallsyms, this >> patch fixes the problem. >> >> 00000000 t __vectors_start >> 00000020 A cpu_v7_suspend_size >> 00001000 t __stubs_start >> 00001004 t vector_rst >> 00001020 t vector_irq >> 000010a0 t vector_dabt >> 00001120 t vector_pabt >> 000011a0 t vector_und >> 00001220 t vector_addrexcptn >> 00001224 t vector_fiq >> 00001224 T vector_fiq_offset >> >> The issue can be fixed in scripts/kallsyms.c too, but looks this >> approach is easier. > > This fix looks hacky; if these symbols are not available, don't just > remove them from /proc/kallsyms, but don't put them in the kernel at > all. > > That way, they won't interfere with other kallsyms uses (eg. backtrace).
Yes, I agree.
> Or, better, figure out a smart way of excluding them by knowing why > these symbol addresses are wrong.
Actually the problem is caused by commit b9b32bf70f2(ARM: use linker magic for vectors and vector stubs), maybe Russell can figure out a smart way to exclude these symbols.
Thanks, -- Ming Lei
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