On 10.03.21 17:49, Philippe Gerum wrote: > > Jan Kiszka <[email protected]> writes: > >> On 09.03.21 05:45, hongzha1 via Xenomai wrote: >>> Ask for switching back to oob mode once ptrace core tell that >>> current is resuming from a stopped state, leaving space for >>> other runnable RT threads of the process to take over. >>> >>> Signed-off-by: hongzha1 <[email protected]> >>> >>> diff --git a/kernel/cobalt/dovetail/kevents.c >>> b/kernel/cobalt/dovetail/kevents.c >>> index 966a63ce0..a640c4d9e 100644 >>> --- a/kernel/cobalt/dovetail/kevents.c >>> +++ b/kernel/cobalt/dovetail/kevents.c >>> @@ -492,6 +492,8 @@ static void handle_ptrace_cont(void) >>> unregister_debugged_thread(curr); >>> >>> xnthread_set_localinfo(curr, XNHICCUP); >>> + >>> + dovetail_request_ucall(current); >>> } >>> >>> xnlock_put_irqrestore(&nklock, s); >>> diff --git a/kernel/cobalt/dovetail/sched.c b/kernel/cobalt/dovetail/sched.c >>> index de7c43b70..2bdddfeef 100644 >>> --- a/kernel/cobalt/dovetail/sched.c >>> +++ b/kernel/cobalt/dovetail/sched.c >>> @@ -56,9 +56,21 @@ int pipeline_leave_inband(void) >>> >>> int pipeline_leave_oob_prepare(void) >>> { >>> - dovetail_leave_oob(); >>> + int suspmask = XNRELAX; >>> + struct xnthread *curr = xnthread_current(); >>> >>> - return XNRELAX; >>> + dovetail_leave_oob(); >>> + /* >>> + * If current is being debugged, record that it should migrate >>> + * back in case it resumes in userspace. If it resumes in >>> + * kernel space, i.e. over a restarting syscall, the >>> + * associated hardening will clear XNCONTHI. >>> + */ >>> + if (xnthread_test_state(curr, XNSSTEP)) { >>> + xnthread_set_info(curr, XNCONTHI); >>> + suspmask |= XNDBGSTOP; >>> + } >>> + return suspmask; >>> } >>> >>> void pipeline_leave_oob_finish(void) >>> >> >> I've applied this to wip/dovetail, but that alone does not fix >> ptrace/gdb use cases yet: >> >> (gdb latency -> run) >> [ 52.097078] ------------[ cut here ]------------ >> [ 52.097079] WARNING: CPU: 2 PID: 1318 at ../kernel/irq/pipeline.c:316 >> inband_irq_enable+0x10/0x20 >> [ 52.097079] Modules linked in: 9p >> [ 52.097080] CPU: 2 PID: 1318 Comm: latency Not tainted 5.10.19+ #41 >> [ 52.097080] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS >> rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 >> [ 52.097080] IRQ stage: Linux >> [ 52.097081] RIP: 0010:inband_irq_enable+0x10/0x20 >> [ 52.097081] Code: 00 00 00 01 75 ee e8 cf fa ff ff 53 9d 5b c3 66 66 2e >> 0f 1f 84 00 00 00 00 00 80 3d 9a 38 b3 02 00 75 09 9c 58 f6 c4 02 75 02 <0f> >> 0b eb 8c 66 66 2e 0f 1f 84 00 00 00 00 00 90 0f 1f 44 00 00 48 >> [ 52.097081] RSP: 0000:ffffc90000783f20 EFLAGS: 00010046 >> [ 52.097082] RAX: 0000000000000046 RBX: ffffc90000783f58 RCX: >> 0000000000000000 >> [ 52.097082] RDX: ffffc90000783ef0 RSI: ffffffff8109e600 RDI: >> ffffffff81d4eee2 >> [ 52.097082] RBP: ffff888006e70000 R08: 0000000000000000 R09: >> 0000000000000000 >> [ 52.097083] R10: 0000000000000000 R11: 0000000000000000 R12: >> 0000000000004000 >> [ 52.097083] R13: 0000000000000000 R14: 0000000000000000 R15: >> 0000000000000000 >> [ 52.097083] FS: 00007ffff7fe6640(0000) GS:ffff88803ed00000(0000) >> knlGS:0000000000000000 >> [ 52.097084] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [ 52.097084] CR2: 00007ffff7243610 CR3: 00000000070c6001 CR4: >> 0000000000370ee0 >> [ 52.097084] Call Trace: >> [ 52.097084] noist_exc_debug+0xf7/0x180 >> [ 52.097085] ? asm_exc_debug+0x23/0x30 >> [ 52.097085] asm_exc_debug+0x2b/0x30 >> [ 52.097085] RIP: 0033:0x401df3 >> [ 52.097086] Code: 00 00 e9 b0 fb ff ff ff 25 62 44 20 00 68 44 00 00 00 >> e9 a0 fb ff ff ff 25 5a 44 20 00 68 45 00 00 00 e9 90 fb ff ff 31 ed 90 <e8> >> f9 30 01 00 48 8d 65 d8 5b 41 5c 41 5d 41 70 44 40 00 48 c7 c1 >> [ 52.097086] RSP: 002b:00007fffffffe1c0 EFLAGS: 00000346 >> [ 52.097086] RAX: 00007ffff7ffe0e0 RBX: 00007ffff7ffe0e0 RCX: >> 00007ffff7df23c7 >> [ 52.097087] RDX: 0000103e00000000 RSI: 0000000000000000 RDI: >> 0000000000000000 >> [ 52.097087] RBP: 00007fffffffe3a0 R08: 00007ffff6e8f008 R09: >> 0000000000000009 >> [ 52.097087] R10: 00007ffff7ffd990 R11: 0000000000000206 R12: >> 0000000000000000 >> [ 52.097087] R13: 00007ffff7ffe110 R14: 00007ffff7ffe110 R15: >> 00007ffff7fe6640 >> [ 52.097088] irq event stamp: 0 >> [ 52.097088] hardirqs last enabled at (0): [<0000000000000000>] 0x0 >> [ 52.097088] hardirqs last disabled at (0): [<ffffffff8106c648>] >> copy_process+0x718/0x1cd0 >> [ 52.097089] softirqs last enabled at (0): [<ffffffff8106c648>] >> copy_process+0x718/0x1cd0 >> [ 52.097089] softirqs last disabled at (0): [<0000000000000000>] 0x0 >> [ 52.097089] ---[ end trace b07496576d3779dc ]--- >> >> Do I miss some other patch? >> >> Jan > > This may help: > > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c > index 719ef25e43d0cd1..f15a07967070264 100644 > --- a/arch/x86/kernel/traps.c > +++ b/arch/x86/kernel/traps.c > @@ -1025,7 +1025,7 @@ static __always_inline void exc_debug_user(struct > pt_regs *regs, > goto out; > > /* It's safe to allow irq's after DR6 has been saved */ > - local_irq_enable(); > + local_irq_enable_full(); > > if (v8086_mode(regs)) { > handle_vm86_trap((struct kernel_vm86_regs *)regs, 0, > X86_TRAP_DB); > @@ -1038,7 +1038,7 @@ static __always_inline void exc_debug_user(struct > pt_regs *regs, > send_sigtrap(regs, 0, get_si_code(dr6)); > > out_irq: > - local_irq_disable(); > + local_irq_disable_full(); > out: > instrumentation_end(); > irqentry_exit_to_user_mode(regs); >
Yep, better. Please queue up. Thanks, Jan -- Siemens AG, T RDA IOT Corporate Competence Center Embedded Linux
