Re: [Crash-utility] [PATCH] ARM: fix unwinding on recent kernels

On Sat, Feb 11, 2012 at 08:00:34PM +0530, Rabin Vincent wrote: > Unwinding doesn't work on recent ARM kernels since after the following > commit the kernel doesn't perform the prel31_to_addr() conversion of the > offsets in the index table. The leads to crash not finding the correct > unwind instructions. > > http://git.kernel.org/linus/de66a979012dbc66b1ec0125795a3f79ee667b8a > > The patch below makes crash do the conversion itself if necessary. > > Rabin > > diff --git a/unwind_arm.c b/unwind_arm.c > index d86ec63..e804cfb 100644 > --- a/unwind_arm.c > +++ b/unwind_arm.c > @@ -71,6 +71,8 @@ struct unwind_table { > static struct unwind_table *kernel_unwind_table; > static struct unwind_table *module_unwind_tables; > > +static int index_in_prel31; > + > struct unwind_ctrl_block { > ulong vrs[16]; > ulong insn; > @@ -104,6 +106,7 @@ static int is_core_kernel_text(ulong); > static struct unwind_table *search_table(ulong); > static struct unwind_idx *search_index(const struct unwind_table > *, ulong); > static ulong prel31_to_addr(ulong, ulong); > +static void index_prel31_to_addr(struct unwind_table *); > static int unwind_frame(struct stackframe *, ulong); > > /* > @@ -187,6 +190,8 @@ init_kernel_unwind_table(void) > goto fail; > } > > + index_in_prel31 = > !is_kernel_text(kernel_unwind_table->idx[0].addr); Maybe add some comment explaining why we do this check (a reference to the kernel commit perhaps)?