Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [RFC PATCH] kernel/kallsyms.c: only show legal kernel symbol | Date | Thu, 24 Oct 2013 11:51:18 +1030 |
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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).
Or, better, figure out a smart way of excluding them by knowing why these symbol addresses are wrong.
Thanks, Rusty.
> Cc: Russell King <linux@arm.linux.org.uk> > Cc: linux-arm-kernel@lists.infradead.org > Cc: Rusty Russell <rusty@rustcorp.com.au> > Cc: Chen Gang <gang.chen@asianux.com> > Signed-off-by: Ming Lei <tom.leiming@gmail.com> > --- > kernel/kallsyms.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c > index 3127ad5..184f271 100644 > --- a/kernel/kallsyms.c > +++ b/kernel/kallsyms.c > @@ -543,7 +543,7 @@ static int s_show(struct seq_file *m, void *p) > tolower(iter->type); > seq_printf(m, "%pK %c %s\t[%s]\n", (void *)iter->value, > type, iter->name, iter->module_name); > - } else > + } else if (iter->value >= CONFIG_PAGE_OFFSET) > seq_printf(m, "%pK %c %s\n", (void *)iter->value, > iter->type, iter->name); > return 0; > -- > 1.7.9.5
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