On Thu, Apr 24, 2014 at 04:50:25PM +0800, Alex Shi wrote:
I caught the following issue few times on my panda board on lsk. but I track the code path, looks like the upstream kernel has the same problem too.
...
[ 30.733612] [<c0008417>] (do_undefinstr+0x10b/0x13c) from [<c050cbe3>] (__und_svc_finish+0x1/0x3e) [ 30.743103] Exception stack(0xedd5fc50 to 0xedd5fc98) [ 30.748443] fc40: c13c14e0 80000000 00000080 00000000 [ 30.757141] fc60: c13c14e0 0000000c eac67284 c13c14e0 edc11518 c0df95c0 c0824410 eac67240 [ 30.765808] fc80: 00000000 edd5fcd8 c00171f9 c00cf998 80000133 ffffffff [ 30.772827] [<c050cbe3>] (__und_svc_finish+0x1/0x3e) from [<c00cf998>] (page_mapping+0x20/0x38) [ 30.782073] [<c00cf998>] (page_mapping+0x20/0x38) from [<c00171f9>] (flush_dcache_page+0x1d/0x60)
The real question is why is page_mapping triggering an undefined instruction exception. That I have no answer for.
This function is a hot path, so I doubt that it really is an undefined instruction. I suspect either your CPU has an erratum, or you have hardware problems.