On Fri, 2023-09-22 at 07:52 +0100, anton.iva...@cambridgegreys.com
wrote:
>
> +++ b/arch/um/include/asm/processor-generic.h
> @@ -44,6 +44,9 @@ struct thread_struct {
> } cb;
> } u;
> } request;
> +#if defined(CONFIG_PREEMPT) || defined(CONFIG_PREEMPT_VOLUNTARY)
> + u8 fpu[2048] __aligned(64); /* Intel docs require xsave/xrestore area to
> be aligned to 64 bytes */
> +#endif
Looks like you used spaces instead of tabs in a few places such as here.
> +#ifdef CONFIG_64BIT
> + if (likely(cpu_has(&boot_cpu_data, X86_FEATURE_XSAVEOPT)))
> + __builtin_ia32_xsaveopt64(¤t->thread.fpu,
> KNOWN_387_FEATURES);
> + else {
> + if (likely(cpu_has(&boot_cpu_data, X86_FEATURE_XSAVE)))
> + __builtin_ia32_xsave64(¤t->thread.fpu,
> KNOWN_387_FEATURES);
> + else
> + __builtin_ia32_fxsave64(¤t->thread.fpu);
> + }
Still think the else if chains would look better, but it also doesn't
matter much.
> mm = &init_mm;
> hvc = INIT_HVC(mm, force, userspace);
> +
> + preempt_disable();
Also here spaces instead of tabs. Interesting you display tabs as 4
spaces when the kernel really does everything with tabs being 8 spaces
wide :)
But anyway that's all nitpicking, the real problem I found when running
this now was this:
BUG: sleeping function called from invalid context at
kernel/locking/rwsem.c:1519
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 282, name: startup.sh
preempt_count: 2, expected: 0
no locks held by startup.sh/282.
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<0000000060044b82>] copy_process+0xa02/0x244e
softirqs last enabled at (0): [<0000000060044b82>] copy_process+0xa02/0x244e
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 0 PID: 282 Comm: startup.sh Not tainted 6.6.0-rc1 #147
Stack:
7229be60 60500273 00000002 6003cfc9
606bd782 00000000 60b3e968 00000000
7229bea0 60526312 00000081 00000000
Call Trace:
[<6051cbaa>] ? _printk+0x0/0x94
[<6002a5b4>] show_stack+0x13d/0x14c
[<60500273>] ? dump_stack_print_info+0xde/0xed
[<6003cfc9>] ? um_set_signals+0x0/0x3f
[<60526312>] dump_stack_lvl+0x62/0x96
[<6051cbaa>] ? _printk+0x0/0x94
[<6052729b>] ? debug_lockdep_rcu_enabled+0x0/0x3b
[<60526360>] dump_stack+0x1a/0x1c
[<60073561>] __might_resched+0x2bb/0x2d9
[<60073640>] __might_sleep+0xc1/0xcb
[<6052bad8>] down_read+0x32/0x1c3
[<6002c94e>] force_flush_all+0x74/0x105
[<6002926e>] fork_handler+0x14/0x96
I had enabled CONFIG_DEBUG_ATOMIC_SLEEP because that's actually
something I'd really like to have in our testing.
But with that issue I don't even know how we get there really. It
doesn't even happen every time we fork?
I'll dig a little bit, but did you try enabling
CONFIG_DEBUG_ATOMIC_SLEEP also?
johannes
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