Re: [PATCH v2 00/14] hrtimer Rust API

[Dirk Behme]

On 18.09.2024 00:27, Andreas Hindborg wrote:
> Hi!
>
> This series adds support for using the `hrtimer` subsystem from Rust code.
>
> I tried breaking up the code in some smaller patches, hopefully that will
> ease the review process a bit.

Just fyi, having all 14 patches applied I get [1] on the first (doctest) 
Example from hrtimer.rs.

This is from lockdep:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/locking/lockdep.c#n4785

Having just a quick look I'm not sure what the root cause is. Maybe 
mutex in interrupt context? Or a more subtle one?

Best regards

Dirk

[1]

    # rust_doctest_kernel_hrtimer_rs_0.location: rust/kernel/hrtimer.rs:10
rust_doctests_kernel: Timer called

=============================
[ BUG: Invalid wait context ]
6.11.0-rc1-arm64 #28 Tainted: G                 N
-----------------------------
swapper/5/0 is trying to lock:
ffff0004409ab900 (rust/doctests_kernel_generated.rs:1238){+.+.}-{3:3}, 
at: rust_helper_mutex_lock+0x10/0x18
other info that might help us debug this:
context-{2:2}
no locks held by swapper/5/0.
stack backtrace:
CPU: 5 UID: 0 PID: 0 Comm: swapper/5 Tainted: G N 6.11.0-rc1-arm64 #28
Tainted: [N]=TEST
Hardware name: ARM64 based board (DT)
Call trace:
 $x.11+0x98/0xb4
 show_stack+0x14/0x1c
 $x.3+0x3c/0x94
 dump_stack+0x14/0x1c
 $x.205+0x538/0x594
 $x.179+0xd0/0x18c
 __mutex_lock+0xa0/0xa4
 mutex_lock_nested+0x20/0x28
 rust_helper_mutex_lock+0x10/0x18

_RNvXs_NvNvNvCslTRHJHclVGW_25doctests_kernel_generated32rust_doctest_kernel_hrtimer_rs_04main41__doctest_main_rust_kernel_hrtimer_rs_10_0NtB4_17ArcIntrusiveTimerNtNtCsclYTRz49wqv_6kernel7hrtimer13TimerCallback3run+0x5c/0xd0

_RNvXs1_NtNtCsclYTRz49wqv_6kernel7hrtimer3arcINtNtNtB9_4sync3arc3ArcNtNvNvNvCslTRHJHclVGW_25doctests_kernel_generated32rust_doctest_kernel_hrtimer_rs_04main41__doctest_main_rust_kernel_hrtimer_rs_10_017ArcIntrusiveTimerENtB7_16RawTimerCallback3runB1b_+0x20/0x2c
 $x.90+0x64/0x70
 hrtimer_interrupt+0x1d4/0x2ac
 arch_timer_handler_phys+0x34/0x40
 $x.62+0x50/0x54
 generic_handle_domain_irq+0x28/0x40
 $x.154+0x58/0x6c
 $x.471+0x10/0x20
 el1_interrupt+0x70/0x94
 el1h_64_irq_handler+0x14/0x1c
 el1h_64_irq+0x64/0x68
 arch_local_irq_enable+0x4/0x8
 cpuidle_enter+0x34/0x48
 $x.37+0x58/0xe4
 cpu_startup_entry+0x30/0x34
 $x.2+0xf8/0x118
 $x.13+0x0/0x4
rust_doctests_kernel: Timer called
rust_doctests_kernel: Timer called
rust_doctests_kernel: Timer called
rust_doctests_kernel: Timer called
rust_doctests_kernel: Counted to 5
    ok 22 rust_doctest_kernel_hrtimer_rs_0
    # rust_doctest_kernel_hrtimer_rs_1.location: rust/kernel/hrtimer.rs:137
rust_doctests_kernel: Hello from the future
rust_doctests_kernel: Flag raised
    ok 23 rust_doctest_kernel_hrtimer_rs_1
    # rust_doctest_kernel_hrtimer_rs_2.location: rust/kernel/hrtimer.rs:76
rust_doctests_kernel: Timer called
rust_doctests_kernel: Flag raised
    ok 24 rust_doctest_kernel_hrtimer_rs_2