[+cc Christoph Lameter, Pekka Enberg ] Hi Meelis, On 06/16/2014 05:21 AM, Meelis Roos wrote:
Back to an old dragon that seems to have more heads than thought. Background is that I got RED state exceptions from recursive faults on sparc64 during reboot via PROM, from running PROM code where PROM has all the cobtrol over the machine. In Sun Ultra 5 and Sun Blade 100 it resulted in RED state exception that looped and hung the machine. This is still a problem in current kernels. Now while debugging a different issue on Sun Fire V100, I noticed a different crash dump on reboot, showing also recursive fault from PROM space. The messages are different (because of newer PROM generation?) but the problem seems same, except no hang happens - that's why I had not noticed it before. Since V100 has LOM (remote lights-out management), I could test it more easily and decided to bisect it.
Is still only with the SLAB allocator and modular CONFIG_SUN_OPENPROMFS?
but it came out clearly finally (each bad commit was clearly bad, each good commit was tested for 3 reboots without a problem). Bisect resulted in his commit being at fault: 8cb06c983822103da1cfe57b9901e60a00e61f67 is the first bad commit commit 8cb06c983822103da1cfe57b9901e60a00e61f67 Author: Peter Hurley<peter@xxxxxxxxxxxxxxxxxx> Date: Sat Jun 15 10:21:18 2013 -0400 n_tty: Remove alias ptrs in __receive_buf() The char and flag buffer local alias pointers, p and f, are unnecessary; remove them. Signed-off-by: Peter Hurley<peter@xxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman<gregkh@xxxxxxxxxxxxxxxxxxx> :040000 040000 ddc901fe810f43bc06a64397735b469b11e403e8 96d92e4e242c4b2ff11b25c005bccd093865b350 M driversAnd it was the same commit [8cb06c983822103da1cfe57b9901e60a00e61f67] there. So something seems to trigger with this commit. ttyS0 is sunsu conole on V100. Ultra 5 had sunsab. So the serial driver seems to be at least different. David, can you suggest a way to dump the whole state of sparc64 MMU to see if we leave some state different than before on reboot PROM call?
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