Hi, I want to use new syscall io_uring in mips, Problem: Running ./liburing/examples/io_uring-cp of liburing in mips kernel, [ 132.538431] do_cpu invoked from kernel context![#1]: [ 132.597936] CPU: 2 PID: 4154 Comm: iou-wrk-4153 Not tainted 5.14.0-rc1+ #5 [ 132.680373] Hardware name: THTF CQTL630 Series/THTF-LS3A4000-7A1000-1W-VB1-ML4A, BIOS V2.0.3 05/08/2020 [ 133.560951] Hi : 0000000000000002 [ 133.603728] Lo : 000000000c49ba60 [ 133.646499] epc : ffffffff80217670 _save_fp+0x10/0xa0 [ 133.709104] ra : ffffffff80cb9c44 __schedule+0x574/0xad8 [ 133.775875] Status: 5400cce2 KX SX UX KERNEL EXL [ 133.832222] Cause : 1000002c (ExcCode 0b) [ 133.880215] PrId : 0014c004 (ICT Loongson-3) [ 135.382659] Call Trace: [ 135.411868] [<ffffffff80217670>] _save_fp+0x10/0xa0 [ 135.470296] [<ffffffff80cb9c44>] __schedule+0x574/0xad8 [ 135.532893] [<ffffffff80cba22c>] schedule+0x84/0x138 [ 135.592361] [<ffffffff80cbf714>] schedule_timeout+0x1bc/0x3c0 [ 135.661219] [<ffffffff80510588>] io_wqe_worker+0x110/0x350 [ 135.726947] [<ffffffff80205a6c>] ret_from_kernel_thread+0x14/0x1c [ 135.799981] [ 135.817718] Code: 000c6940 05a10011 00000000 <f4810a00> f4830a20 f4850a40 f4870a60 f4890a80 f48b0aa0 Reason: io-wq, fork worker threads from original user task(commit 3bfe6106693b6b4ba175ad1f929c4660b8f59ca8). This causes copy_thread with TIF_USEDFPU flag in mips, meaning save_fp in switch_to, triggering do_cpu trap, however cpid 1(fpu) don't allow kernel to use. Fix: clear FPU flag in kernel IO_WORKER thread_copy branch. wangyangbo (1): MIPS: Fix fpu trap invoked by io-worker arch/mips/kernel/process.c | 3 +++ 1 file changed, 3 insertions(+) -- 2.20.1
