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Add monitor factory in RROS #24

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shannmu opened this issue Feb 4, 2024 · 0 comments
Open

Add monitor factory in RROS #24

shannmu opened this issue Feb 4, 2024 · 0 comments

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@shannmu
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shannmu commented Feb 4, 2024

The RROS project lacks the capability for inter-thread synchronization, including: mutexs, semaphores, and condition variables. A monitor factory is needed to implement this functionality. For real-time operating systems, it is necessary to ensure that the kernel does not experience deadlock while implementing synchronization mechanisms, and to implement priority inheritance and the ceiling protocol.

shannmu added a commit to shannmu/RROS that referenced this issue Feb 4, 2024
The ` monitor factory` has implemented a synchronization mechanism inter threads, providing three types of synchronization methods to the user mode: mutexes, semaphores, and condition variables. During the implementation process, I believe it is worth mentioning that the following features were added or modified:

- Fixed bugs in `mutex.rs`.

- Added a `u_window` field to the RrosThread structure, which is used for kernel mode and user mode to interact data through shared memory.

- As mentioned above, the interaction of some data between kernel mode and user mode adopts shared memory. This change fixed a bug in control.rs, which uses `mmap` to create shared memory; and it implemented a memory allocator for shared memory.

- Added the setting of thread FIFO scheduling strategy and fixed some functions related to thread scheduling.

BUPT-OS#24
shannmu added a commit to shannmu/RROS that referenced this issue Nov 11, 2024
The ` monitor factory` has implemented a synchronization mechanism inter threads, providing three types of synchronization methods to the user mode: mutexes, semaphores, and condition variables. During the implementation process, I believe it is worth mentioning that the following features were added or modified:

- Fixed bugs in `mutex.rs`.

- Added a `u_window` field to the RrosThread structure, which is used for kernel mode and user mode to interact data through shared memory.

- As mentioned above, the interaction of some data between kernel mode and user mode adopts shared memory. This change fixed a bug in control.rs, which uses `mmap` to create shared memory; and it implemented a memory allocator for shared memory.

- Added the setting of thread FIFO scheduling strategy and fixed some functions related to thread scheduling.

BUPT-OS#24
shannmu pushed a commit to shannmu/RROS that referenced this issue Dec 15, 2024
The following processes run into a deadlock. CPU 41 was waiting for CPU 29
to handle a CSD request while holding spinlock "crashdump_lock", but CPU 29
was hung by that spinlock with IRQs disabled.

  PID: 17360    TASK: ffff95c1090c5c40  CPU: 41  COMMAND: "mrdiagd"
  !# 0 [ffffb80edbf37b58] __read_once_size at ffffffff9b871a40 include/linux/compiler.h:185:0
  !# 1 [ffffb80edbf37b58] atomic_read at ffffffff9b871a40 arch/x86/include/asm/atomic.h:27:0
  !# 2 [ffffb80edbf37b58] dump_stack at ffffffff9b871a40 lib/dump_stack.c:54:0
   # 3 [ffffb80edbf37b78] csd_lock_wait_toolong at ffffffff9b131ad5 kernel/smp.c:364:0
   # 4 [ffffb80edbf37b78] __csd_lock_wait at ffffffff9b131ad5 kernel/smp.c:384:0
   # 5 [ffffb80edbf37bf8] csd_lock_wait at ffffffff9b13267a kernel/smp.c:394:0
   # 6 [ffffb80edbf37bf8] smp_call_function_many at ffffffff9b13267a kernel/smp.c:843:0
   # 7 [ffffb80edbf37c50] smp_call_function at ffffffff9b13279d kernel/smp.c:867:0
   # 8 [ffffb80edbf37c50] on_each_cpu at ffffffff9b13279d kernel/smp.c:976:0
   # 9 [ffffb80edbf37c78] flush_tlb_kernel_range at ffffffff9b085c4b arch/x86/mm/tlb.c:742:0
   BUPT-OS#10 [ffffb80edbf37cb8] __purge_vmap_area_lazy at ffffffff9b23a1e0 mm/vmalloc.c:701:0
   BUPT-OS#11 [ffffb80edbf37ce0] try_purge_vmap_area_lazy at ffffffff9b23a2cc mm/vmalloc.c:722:0
   BUPT-OS#12 [ffffb80edbf37ce0] free_vmap_area_noflush at ffffffff9b23a2cc mm/vmalloc.c:754:0
   BUPT-OS#13 [ffffb80edbf37cf8] free_unmap_vmap_area at ffffffff9b23bb3b mm/vmalloc.c:764:0
   BUPT-OS#14 [ffffb80edbf37cf8] remove_vm_area at ffffffff9b23bb3b mm/vmalloc.c:1509:0
   BUPT-OS#15 [ffffb80edbf37d18] __vunmap at ffffffff9b23bb8a mm/vmalloc.c:1537:0
   BUPT-OS#16 [ffffb80edbf37d40] vfree at ffffffff9b23bc85 mm/vmalloc.c:1612:0
   BUPT-OS#17 [ffffb80edbf37d58] megasas_free_host_crash_buffer [megaraid_sas] at ffffffffc020b7f2 drivers/scsi/megaraid/megaraid_sas_fusion.c:3932:0
   BUPT-OS#18 [ffffb80edbf37d80] fw_crash_state_store [megaraid_sas] at ffffffffc01f804d drivers/scsi/megaraid/megaraid_sas_base.c:3291:0
   BUPT-OS#19 [ffffb80edbf37dc0] dev_attr_store at ffffffff9b56dd7b drivers/base/core.c:758:0
   BUPT-OS#20 [ffffb80edbf37dd0] sysfs_kf_write at ffffffff9b326acf fs/sysfs/file.c:144:0
   BUPT-OS#21 [ffffb80edbf37de0] kernfs_fop_write at ffffffff9b325fd4 fs/kernfs/file.c:316:0
   BUPT-OS#22 [ffffb80edbf37e20] __vfs_write at ffffffff9b29418a fs/read_write.c:480:0
   BUPT-OS#23 [ffffb80edbf37ea8] vfs_write at ffffffff9b294462 fs/read_write.c:544:0
   BUPT-OS#24 [ffffb80edbf37ee8] SYSC_write at ffffffff9b2946ec fs/read_write.c:590:0
   BUPT-OS#25 [ffffb80edbf37ee8] SyS_write at ffffffff9b2946ec fs/read_write.c:582:0
   BUPT-OS#26 [ffffb80edbf37f30] do_syscall_64 at ffffffff9b003ca9 arch/x86/entry/common.c:298:0
   BUPT-OS#27 [ffffb80edbf37f58] entry_SYSCALL_64 at ffffffff9ba001b1 arch/x86/entry/entry_64.S:238:0

  PID: 17355    TASK: ffff95c1090c3d80  CPU: 29  COMMAND: "mrdiagd"
  !# 0 [ffffb80f2d3c7d30] __read_once_size at ffffffff9b0f2ab0 include/linux/compiler.h:185:0
  !# 1 [ffffb80f2d3c7d30] native_queued_spin_lock_slowpath at ffffffff9b0f2ab0 kernel/locking/qspinlock.c:368:0
   # 2 [ffffb80f2d3c7d58] pv_queued_spin_lock_slowpath at ffffffff9b0f244b arch/x86/include/asm/paravirt.h:674:0
   # 3 [ffffb80f2d3c7d58] queued_spin_lock_slowpath at ffffffff9b0f244b arch/x86/include/asm/qspinlock.h:53:0
   # 4 [ffffb80f2d3c7d68] queued_spin_lock at ffffffff9b8961a6 include/asm-generic/qspinlock.h:90:0
   # 5 [ffffb80f2d3c7d68] do_raw_spin_lock_flags at ffffffff9b8961a6 include/linux/spinlock.h:173:0
   # 6 [ffffb80f2d3c7d68] __raw_spin_lock_irqsave at ffffffff9b8961a6 include/linux/spinlock_api_smp.h:122:0
   # 7 [ffffb80f2d3c7d68] _raw_spin_lock_irqsave at ffffffff9b8961a6 kernel/locking/spinlock.c:160:0
   # 8 [ffffb80f2d3c7d88] fw_crash_buffer_store [megaraid_sas] at ffffffffc01f8129 drivers/scsi/megaraid/megaraid_sas_base.c:3205:0
   # 9 [ffffb80f2d3c7dc0] dev_attr_store at ffffffff9b56dd7b drivers/base/core.c:758:0
   BUPT-OS#10 [ffffb80f2d3c7dd0] sysfs_kf_write at ffffffff9b326acf fs/sysfs/file.c:144:0
   BUPT-OS#11 [ffffb80f2d3c7de0] kernfs_fop_write at ffffffff9b325fd4 fs/kernfs/file.c:316:0
   BUPT-OS#12 [ffffb80f2d3c7e20] __vfs_write at ffffffff9b29418a fs/read_write.c:480:0
   BUPT-OS#13 [ffffb80f2d3c7ea8] vfs_write at ffffffff9b294462 fs/read_write.c:544:0
   BUPT-OS#14 [ffffb80f2d3c7ee8] SYSC_write at ffffffff9b2946ec fs/read_write.c:590:0
   BUPT-OS#15 [ffffb80f2d3c7ee8] SyS_write at ffffffff9b2946ec fs/read_write.c:582:0
   BUPT-OS#16 [ffffb80f2d3c7f30] do_syscall_64 at ffffffff9b003ca9 arch/x86/entry/common.c:298:0
   BUPT-OS#17 [ffffb80f2d3c7f58] entry_SYSCALL_64 at ffffffff9ba001b1 arch/x86/entry/entry_64.S:238:0

The lock is used to synchronize different sysfs operations, it doesn't
protect any resource that will be touched by an interrupt. Consequently
it's not required to disable IRQs. Replace the spinlock with a mutex to fix
the deadlock.

Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Link: https://lore.kernel.org/r/20230828221018.19471-1-junxiao.bi@oracle.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
shannmu pushed a commit to shannmu/RROS that referenced this issue Dec 15, 2024
Inline calls to bpf_get_smp_processor_id() helper in the JIT by emitting
a read from struct thread_info. The SP_EL0 system register holds the
pointer to the task_struct and thread_info is the first member of this
struct. We can read the cpu number from the thread_info.

Here is how the ARM64 JITed assembly changes after this commit:

                                      ARM64 JIT
                                     ===========

              BEFORE                                    AFTER
             --------                                  -------

int cpu = bpf_get_smp_processor_id();        int cpu = bpf_get_smp_processor_id();

mov     x10, #0xfffffffffffff4d0             mrs     x10, sp_el0
movk    x10, #0x802b, lsl BUPT-OS#16                ldr     w7, [x10, BUPT-OS#24]
movk    x10, #0x8000, lsl BUPT-OS#32
blr     x10
add     x7, x0, #0x0

               Performance improvement using benchmark[1]

./benchs/run_bench_trigger.sh glob-arr-inc arr-inc hash-inc

+---------------+-------------------+-------------------+--------------+
|      Name     |      Before       |        After      |   % change   |
|---------------+-------------------+-------------------+--------------|
| glob-arr-inc  | 23.380 ± 1.675M/s | 25.893 ± 0.026M/s |   + 10.74%   |
| arr-inc       | 23.928 ± 0.034M/s | 25.213 ± 0.063M/s |   + 5.37%    |
| hash-inc      | 12.352 ± 0.005M/s | 12.609 ± 0.013M/s |   + 2.08%    |
+---------------+-------------------+-------------------+--------------+

[1] anakryiko/linux@8dec900975ef

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240502151854.9810-5-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
shannmu pushed a commit to shannmu/RROS that referenced this issue Dec 15, 2024
Puranjay Mohan says:

====================
bpf: Inline helpers in arm64 and riscv JITs

Changes in v5 -> v6:
arm64 v5: https://lore.kernel.org/all/20240430234739.79185-1-puranjay@kernel.org/
riscv v2: https://lore.kernel.org/all/20240430175834.33152-1-puranjay@kernel.org/
- Combine riscv and arm64 changes in single series
- Some coding style fixes

Changes in v4 -> v5:
v4: https://lore.kernel.org/all/20240429131647.50165-1-puranjay@kernel.org/
- Implement the inlining of the bpf_get_smp_processor_id() in the JIT.

NOTE: This needs to be based on:
https://lore.kernel.org/all/20240430175834.33152-1-puranjay@kernel.org/
to be built.

Manual run of bpf-ci with this series rebased on above:
kernel-patches/bpf#6929

Changes in v3 -> v4:
v3: https://lore.kernel.org/all/20240426121349.97651-1-puranjay@kernel.org/
- Fix coding style issue related to C89 standards.

Changes in v2 -> v3:
v2: https://lore.kernel.org/all/20240424173550.16359-1-puranjay@kernel.org/
- Fixed the xlated dump of percpu mov to "r0 = &(void __percpu *)(r0)"
- Made ARM64 and x86-64 use the same code for inlining. The only difference
  that remains is the per-cpu address of the cpu_number.

Changes in v1 -> v2:
v1: https://lore.kernel.org/all/20240405091707.66675-1-puranjay12@gmail.com/
- Add a patch to inline bpf_get_smp_processor_id()
- Fix an issue in MRS instruction encoding as pointed out by Will
- Remove CONFIG_SMP check because arm64 kernel always compiles with CONFIG_SMP

This series adds the support of internal only per-CPU instructions and inlines
the bpf_get_smp_processor_id() helper call for ARM64 and RISC-V BPF JITs.

Here is an example of calls to bpf_get_smp_processor_id() and
percpu_array_map_lookup_elem() before and after this series on ARM64.

                                         BPF
                                        =====
              BEFORE                                       AFTER
             --------                                     -------

int cpu = bpf_get_smp_processor_id();           int cpu = bpf_get_smp_processor_id();
(85) call bpf_get_smp_processor_id#229032       (85) call bpf_get_smp_processor_id#8

p = bpf_map_lookup_elem(map, &zero);            p = bpf_map_lookup_elem(map, &zero);
(18) r1 = map[id:78]                            (18) r1 = map[id:153]
(18) r2 = map[id:82][0]+65536                   (18) r2 = map[id:157][0]+65536
(85) call percpu_array_map_lookup_elem#313512   (07) r1 += 496
                                                (61) r0 = *(u32 *)(r2 +0)
                                                (35) if r0 >= 0x1 goto pc+5
                                                (67) r0 <<= 3
                                                (0f) r0 += r1
                                                (79) r0 = *(u64 *)(r0 +0)
                                                (bf) r0 = &(void __percpu *)(r0)
                                                (05) goto pc+1
                                                (b7) r0 = 0

                                      ARM64 JIT
                                     ===========

              BEFORE                                       AFTER
             --------                                     -------

int cpu = bpf_get_smp_processor_id();           int cpu = bpf_get_smp_processor_id();
mov     x10, #0xfffffffffffff4d0                mrs     x10, sp_el0
movk    x10, #0x802b, lsl BUPT-OS#16                   ldr     w7, [x10, BUPT-OS#24]
movk    x10, #0x8000, lsl BUPT-OS#32
blr     x10
add     x7, x0, #0x0

p = bpf_map_lookup_elem(map, &zero);            p = bpf_map_lookup_elem(map, &zero);
mov     x0, #0xffff0003ffffffff                 mov     x0, #0xffff0003ffffffff
movk    x0, #0xce5c, lsl BUPT-OS#16                    movk    x0, #0xe0f3, lsl BUPT-OS#16
movk    x0, #0xca00                             movk    x0, #0x7c00
mov     x1, #0xffff8000ffffffff                 mov     x1, #0xffff8000ffffffff
movk    x1, #0x8bdb, lsl BUPT-OS#16                    movk    x1, #0xb0c7, lsl BUPT-OS#16
movk    x1, #0x6000                             movk    x1, #0xe000
mov     x10, #0xffffffffffff3ed0                add     x0, x0, #0x1f0
movk    x10, #0x802d, lsl BUPT-OS#16                   ldr     w7, [x1]
movk    x10, #0x8000, lsl BUPT-OS#32                   cmp     x7, #0x1
blr     x10                                     b.cs    0x0000000000000090
add     x7, x0, #0x0                            lsl     x7, x7, BUPT-OS#3
                                                add     x7, x7, x0
                                                ldr     x7, [x7]
                                                mrs     x10, tpidr_el1
                                                add     x7, x7, x10
                                                b       0x0000000000000094
                                                mov     x7, #0x0

              Performance improvement found using benchmark[1]

./benchs/run_bench_trigger.sh glob-arr-inc arr-inc hash-inc

  +---------------+-------------------+-------------------+--------------+
  |      Name     |      Before       |        After      |   % change   |
  |---------------+-------------------+-------------------+--------------|
  | glob-arr-inc  | 23.380 ± 1.675M/s | 25.893 ± 0.026M/s |   + 10.74%   |
  | arr-inc       | 23.928 ± 0.034M/s | 25.213 ± 0.063M/s |   + 5.37%    |
  | hash-inc      | 12.352 ± 0.005M/s | 12.609 ± 0.013M/s |   + 2.08%    |
  +---------------+-------------------+-------------------+--------------+

[1] anakryiko/linux@8dec900975ef

             RISCV64 JIT output for `call bpf_get_smp_processor_id`
            =======================================================

                  Before                           After
                 --------                         -------

           auipc   t1,0x848c                  ld    a5,32(tp)
           jalr    604(t1)
           mv      a5,a0

  Benchmark using [1] on Qemu.

  ./benchs/run_bench_trigger.sh glob-arr-inc arr-inc hash-inc

  +---------------+------------------+------------------+--------------+
  |      Name     |     Before       |       After      |   % change   |
  |---------------+------------------+------------------+--------------|
  | glob-arr-inc  | 1.077 ± 0.006M/s | 1.336 ± 0.010M/s |   + 24.04%   |
  | arr-inc       | 1.078 ± 0.002M/s | 1.332 ± 0.015M/s |   + 23.56%   |
  | hash-inc      | 0.494 ± 0.004M/s | 0.653 ± 0.001M/s |   + 32.18%   |
  +---------------+------------------+------------------+--------------+
====================

Link: https://lore.kernel.org/r/20240502151854.9810-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
shannmu pushed a commit to shannmu/RROS that referenced this issue Dec 15, 2024
scx_ops_bypass() can currently race on the ops enable / disable path as
follows:

1. scx_ops_bypass(true) called on enable path, bypass depth is set to 1
2. An op on the init path exits, which schedules scx_ops_disable_workfn()
3. scx_ops_bypass(false) is called on the disable path, and bypass depth
   is decremented to 0
4. kthread is scheduled to execute scx_ops_disable_workfn()
5. scx_ops_bypass(true) called, bypass depth set to 1
6. scx_ops_bypass() races when iterating over CPUs

While it's not safe to take any blocking locks on the bypass path, it is
safe to take a raw spinlock which cannot be preempted. This patch therefore
updates scx_ops_bypass() to use a raw spinlock to synchronize, and changes
scx_ops_bypass_depth to be a regular int.

Without this change, we observe the following warnings when running the
'exit' sched_ext selftest (sometimes requires a couple of runs):

.[root@virtme-ng sched_ext]# ./runner -t exit
===== START =====
TEST: exit
...
[   14.935078] WARNING: CPU: 2 PID: 360 at kernel/sched/ext.c:4332 scx_ops_bypass+0x1ca/0x280
[   14.935126] Modules linked in:
[   14.935150] CPU: 2 UID: 0 PID: 360 Comm: sched_ext_ops_h Not tainted 6.11.0-virtme BUPT-OS#24
[   14.935192] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[   14.935242] Sched_ext: exit (enabling+all)
[   14.935244] RIP: 0010:scx_ops_bypass+0x1ca/0x280
[   14.935300] Code: ff ff ff e8 48 96 10 00 fb e9 08 ff ff ff c6 05 7b 34 e8 01 01 90 48 c7 c7 89 86 88 87 e8 be 1d f8 ff 90 0f 0b 90 90 eb 95 90 <0f> 0b 90 41 8b 84 24 24 0a 00 00 eb 97 90 0f 0b 90 41 8b 84 24 24
[   14.935394] RSP: 0018:ffffb706c0957ce0 EFLAGS: 00010002
[   14.935424] RAX: 0000000000000009 RBX: 0000000000000001 RCX: 00000000e3fb8b2a
[   14.935465] RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff88a4c080
[   14.935512] RBP: 0000000000009b56 R08: 0000000000000004 R09: 00000003f12e520a
[   14.935555] R10: ffffffff863a9795 R11: 0000000000000000 R12: ffff8fc5fec31300
[   14.935598] R13: ffff8fc5fec31318 R14: 0000000000000286 R15: 0000000000000018
[   14.935642] FS:  0000000000000000(0000) GS:ffff8fc5fe680000(0000) knlGS:0000000000000000
[   14.935684] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   14.935721] CR2: 0000557d92890b88 CR3: 000000002464a000 CR4: 0000000000750ef0
[   14.935765] PKRU: 55555554
[   14.935782] Call Trace:
[   14.935802]  <TASK>
[   14.935823]  ? __warn+0xce/0x220
[   14.935850]  ? scx_ops_bypass+0x1ca/0x280
[   14.935881]  ? report_bug+0xc1/0x160
[   14.935909]  ? handle_bug+0x61/0x90
[   14.935934]  ? exc_invalid_op+0x1a/0x50
[   14.935959]  ? asm_exc_invalid_op+0x1a/0x20
[   14.935984]  ? raw_spin_rq_lock_nested+0x15/0x30
[   14.936019]  ? scx_ops_bypass+0x1ca/0x280
[   14.936046]  ? srso_alias_return_thunk+0x5/0xfbef5
[   14.936081]  ? __pfx_scx_ops_disable_workfn+0x10/0x10
[   14.936111]  scx_ops_disable_workfn+0x146/0xac0
[   14.936142]  ? finish_task_switch+0xa9/0x2c0
[   14.936172]  ? srso_alias_return_thunk+0x5/0xfbef5
[   14.936211]  ? __pfx_scx_ops_disable_workfn+0x10/0x10
[   14.936244]  kthread_worker_fn+0x101/0x2c0
[   14.936268]  ? __pfx_kthread_worker_fn+0x10/0x10
[   14.936299]  kthread+0xec/0x110
[   14.936327]  ? __pfx_kthread+0x10/0x10
[   14.936351]  ret_from_fork+0x37/0x50
[   14.936374]  ? __pfx_kthread+0x10/0x10
[   14.936400]  ret_from_fork_asm+0x1a/0x30
[   14.936427]  </TASK>
[   14.936443] irq event stamp: 21002
[   14.936467] hardirqs last  enabled at (21001): [<ffffffff863aa35f>] resched_cpu+0x9f/0xd0
[   14.936521] hardirqs last disabled at (21002): [<ffffffff863dd0ba>] scx_ops_bypass+0x11a/0x280
[   14.936571] softirqs last  enabled at (20642): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0
[   14.936622] softirqs last disabled at (20637): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0
[   14.936672] ---[ end trace 0000000000000000 ]---
[   14.953282] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[   14.953352] ------------[ cut here ]------------
[   14.953383] WARNING: CPU: 2 PID: 360 at kernel/sched/ext.c:4335 scx_ops_bypass+0x1d8/0x280
[   14.953428] Modules linked in:
[   14.953453] CPU: 2 UID: 0 PID: 360 Comm: sched_ext_ops_h Tainted: G        W          6.11.0-virtme BUPT-OS#24
[   14.953505] Tainted: [W]=WARN
[   14.953527] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[   14.953574] RIP: 0010:scx_ops_bypass+0x1d8/0x280
[   14.953603] Code: c6 05 7b 34 e8 01 01 90 48 c7 c7 89 86 88 87 e8 be 1d f8 ff 90 0f 0b 90 90 eb 95 90 0f 0b 90 41 8b 84 24 24 0a 00 00 eb 97 90 <0f> 0b 90 41 8b 84 24 24 0a 00 00 eb 92 f3 0f 1e fa 49 8d 84 24 f0
[   14.953693] RSP: 0018:ffffb706c0957ce0 EFLAGS: 00010046
[   14.953722] RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000001
[   14.953763] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8fc5fec31318
[   14.953804] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
[   14.953845] R10: ffffffff863a9795 R11: 0000000000000000 R12: ffff8fc5fec31300
[   14.953888] R13: ffff8fc5fec31318 R14: 0000000000000286 R15: 0000000000000018
[   14.953934] FS:  0000000000000000(0000) GS:ffff8fc5fe680000(0000) knlGS:0000000000000000
[   14.953974] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   14.954009] CR2: 0000557d92890b88 CR3: 000000002464a000 CR4: 0000000000750ef0
[   14.954052] PKRU: 55555554
[   14.954068] Call Trace:
[   14.954085]  <TASK>
[   14.954102]  ? __warn+0xce/0x220
[   14.954126]  ? scx_ops_bypass+0x1d8/0x280
[   14.954150]  ? report_bug+0xc1/0x160
[   14.954178]  ? handle_bug+0x61/0x90
[   14.954203]  ? exc_invalid_op+0x1a/0x50
[   14.954226]  ? asm_exc_invalid_op+0x1a/0x20
[   14.954250]  ? raw_spin_rq_lock_nested+0x15/0x30
[   14.954285]  ? scx_ops_bypass+0x1d8/0x280
[   14.954311]  ? __mutex_unlock_slowpath+0x3a/0x260
[   14.954343]  scx_ops_disable_workfn+0xa3e/0xac0
[   14.954381]  ? __pfx_scx_ops_disable_workfn+0x10/0x10
[   14.954413]  kthread_worker_fn+0x101/0x2c0
[   14.954442]  ? __pfx_kthread_worker_fn+0x10/0x10
[   14.954479]  kthread+0xec/0x110
[   14.954507]  ? __pfx_kthread+0x10/0x10
[   14.954530]  ret_from_fork+0x37/0x50
[   14.954553]  ? __pfx_kthread+0x10/0x10
[   14.954576]  ret_from_fork_asm+0x1a/0x30
[   14.954603]  </TASK>
[   14.954621] irq event stamp: 21002
[   14.954644] hardirqs last  enabled at (21001): [<ffffffff863aa35f>] resched_cpu+0x9f/0xd0
[   14.954686] hardirqs last disabled at (21002): [<ffffffff863dd0ba>] scx_ops_bypass+0x11a/0x280
[   14.954735] softirqs last  enabled at (20642): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0
[   14.954782] softirqs last disabled at (20637): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0
[   14.954829] ---[ end trace 0000000000000000 ]---
[   15.022283] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[   15.092282] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[   15.149282] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
ok 1 exit #
=====  END  =====

And with it, the test passes without issue after 1000s of runs:

.[root@virtme-ng sched_ext]# ./runner -t exit
===== START =====
TEST: exit
DESCRIPTION: Verify we can cleanly exit a scheduler in multiple places
OUTPUT:
[    7.412856] sched_ext: BPF scheduler "exit" enabled
[    7.427924] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[    7.466677] sched_ext: BPF scheduler "exit" enabled
[    7.475923] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[    7.512803] sched_ext: BPF scheduler "exit" enabled
[    7.532924] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[    7.586809] sched_ext: BPF scheduler "exit" enabled
[    7.595926] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[    7.661923] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[    7.723923] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
ok 1 exit #
=====  END  =====

=============================

RESULTS:

PASSED:  1
SKIPPED: 0
FAILED:  0

Fixes: f0e1a06 ("sched_ext: Implement BPF extensible scheduler class")
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Richardhongyu pushed a commit that referenced this issue Jan 3, 2025
The ` monitor factory` has implemented a synchronization mechanism inter threads, providing three types of synchronization methods to the user mode: mutexes, semaphores, and condition variables. During the implementation process, I believe it is worth mentioning that the following features were added or modified:

- Fixed bugs in `mutex.rs`.

- Added a `u_window` field to the RrosThread structure, which is used for kernel mode and user mode to interact data through shared memory.

- As mentioned above, the interaction of some data between kernel mode and user mode adopts shared memory. This change fixed a bug in control.rs, which uses `mmap` to create shared memory; and it implemented a memory allocator for shared memory.

- Added the setting of thread FIFO scheduling strategy and fixed some functions related to thread scheduling.

#24
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