On 2019-02-12 12:47:22 [+0000], Bernd Edlinger wrote: > The harden_branch_predictor function uses smp_processor_id, > which complains about being used in a preemptible context: > > BUG: using smp_processor_id() in preemptible [00000000] code: trie_map_rand.e/4938 > caller is debug_smp_processor_id+0x18/0x24 > CPU: 0 PID: 4938 Comm: trie_map_rand.e Not tainted 4.14.93-rt53-g74e4d87 #1 > Hardware name: Altera SOCFPGA > [<8011162c>] (unwind_backtrace) from [<8010bfd4>] (show_stack+0x20/0x24) > [<8010bfd4>] (show_stack) from [<806732e8>] (dump_stack+0x78/0x94) > [<806732e8>] (dump_stack) from [<8041c254>] (check_preemption_disabled+0xec/0x128) > [<8041c254>] (check_preemption_disabled) from [<8041c2a8>] (debug_smp_processor_id+0x18/0x24) > [<8041c2a8>] (debug_smp_processor_id) from [<8011518c>] (__do_user_fault+0x34/0x100) > [<8011518c>] (__do_user_fault) from [<801155d0>] (do_page_fault+0x2f4/0x328) > [<801155d0>] (do_page_fault) from [<80101268>] (do_DataAbort+0x48/0xc8) > [<80101268>] (do_DataAbort) from [<8010d300>] (__dabt_usr+0x40/0x60) > Exception stack(0xae2fdfb0 to 0xae2fdff8) > dfa0: c31b0fc6 76c8f7d8 00000000 00000001 > dfc0: 00000001 00c79780 0004f7f4 00c79780 7ea2e550 7ea2e408 7ea2e58c 3fc99999 > dfe0: 00000100 7ea2e3d0 00033d24 00018edc 600c0010 ffffffff > > Work around the issue by disabling preemption while clearing > the branch predictor table. Can you verify if this only happens on RT or also on !RT? From what it looks like to me, it should also happen on non-RT. Sebastian
