On 04/25/2014 04:57 PM, Russell King - ARM Linux wrote:
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.
Thanks for your response, Russell!
Maybe hardware is not stable. but even so, do you think using down_read rwsem is appropriate in interrupt handler?
Another panic: [ 30.390350] ------------[ cut here ]------------ [ 30.390350] WARNING: at kernel/exit.c:714 do_exit+0x43/0x870() [ 30.400390] Modules linked in: [ 30.405853] CPU: 0 PID: 809 Comm: jbd2/mmcblk0p2- Tainted: G D 3.10.37+ #109 [ 30.414276] [<c001292d>] (unwind_backtrace+0x1/0xcc) from [<c0010279>] (show_stack+0x11/0x14) [ 30.422729] [<c0010279>] (show_stack+0x11/0x14) from [<c0030819>] (warn_slowpath_common+0x45/0x5c) [ 30.432739] [<c0030819>] (warn_slowpath_common+0x45/0x5c) from [<c003089f>] (warn_slowpath_null+0x17/0x1c) [ 30.443084] [<c003089f>] (warn_slowpath_null+0x17/0x1c) from [<c003441b>] (do_exit+0x43/0x870) [ 30.443084] [<c003441b>] (do_exit+0x43/0x870) from [<c00105af>] (die+0x333/0x350) [ 30.458557] [<c00105af>] (die+0x333/0x350) from [<c0008417>] (do_undefinstr+0x10b/0x13c) [ 30.468749] [<c0008417>] (do_undefinstr+0x10b/0x13c) from [<c050cbe3>] (__und_svc_finish+0x1/0x3e) [ 30.476806] Exception stack(0xedd5fc50 to 0xedd5fc98) [ 30.483612] fc40: c13c14e0 80000000 00000080 00000000 [ 30.488555] fc60: c13c14e0 0000000c eac67284 c13c14e0 edc11518 c0df95c0 c0824410 eac67240 [ 30.498504] fc80: 00000000 edd5fcd8 c00171f9 c00cf998 80000133 ffffffff [ 30.504699] [<c050cbe3>] (__und_svc_finish+0x1/0x3e) from [<c00cf998>] (page_mapping+0x20/0x38) [ 30.508514] [<c00cf998>] (page_mapping+0x20/0x38) from [<c00171f9>] (flush_dcache_page+0x1d/0x60) [ 30.518493] [<c00171f9>] (flush_dcache_page+0x1d/0x60) from [<c00e26c3>] (blk_queue_bounce+0x1a3/0x2a0) [ 30.528533] [<c00e26c3>] (blk_queue_bounce+0x1a3/0x2a0) from [<c02ca5bb>] (blk_queue_bio+0x1f/0x364) [ 30.538513] [<c02ca5bb>] (blk_queue_bio+0x1f/0x364) from [<c02c9661>] (generic_make_request+0x65/0x88) [ 30.548522] [<c02c9661>] (generic_make_request+0x65/0x88) from [<c02c96e5>] (submit_bio+0x61/0x104) [ 30.565826] [<c02c96e5>] (submit_bio+0x61/0x104) from [<c010f017>] (_submit_bh+0x127/0x19c) [ 30.572967] [<c010f017>] (_submit_bh+0x127/0x19c) from [<c0194def>] (jbd2_journal_commit_transaction+0x70b/0x161c)