git: 89889ab470b9 - main - LinuxKPI: Allow wake_up to be executed within a critical section

The branch main has been updated by wulf:

URL: https://cgit.FreeBSD.org/src/commit/?id=89889ab470b9f1a1cd36913dd219b78efbf484df

commit 89889ab470b9f1a1cd36913dd219b78efbf484df
Author:     Vladimir Kondratyev <wulf@FreeBSD.org>
AuthorDate: 2022-01-18 20:14:13 +0000
Commit:     Vladimir Kondratyev <wulf@FreeBSD.org>
CommitDate: 2022-01-18 20:14:13 +0000

    LinuxKPI: Allow wake_up to be executed within a critical section
    
    by replaceing of spin_lock() call with spin_lock_irqsave()
    
    This fixes following panic in drm-kmod:
    
    panic: mi_switch: switch in a critical section
    cpuid = 2
    time = 1636939794
    KDB: stack backtrace:
    db_trace_self_wrapper() at db_trace_self_wrapper+0x2b
    vpanic() at vpanic+0x187
    panic() at panic+0x43
    mi_switch() at mi_switch+0x198
    __mtx_lock_sleep() at __mtx_lock_sleep+0x1c9
    __mtx_lock_flags() at __mtx_lock_flags+0xa2
    linux_wake_up() at linux_wake_up+0x38
    __active_retire() at __active_retire+0xb7
    dma_fence_signal() at dma_fence_signal+0x100
    dma_resv_add_shared_fence() at dma_resv_add_shared_fence+0x96
    i915_gem_do_execbuffer() at i915_gem_do_execbuffer+0x11d0
    i915_gem_execbuffer2_ioctl() at i915_gem_execbuffer2_ioctl+0x19a
    drm_ioctl_kernel() at drm_ioctl_kernel+0x72
    drm_ioctl() at drm_ioctl+0x2c4
    linux_file_ioctl() at linux_file_ioctl+0x297
    kern_ioctl() at kern_ioctl+0x1dc
    sys_ioctl() at sys_ioctl+0x124
    amd64_syscall() at amd64_syscall+0x124
    fast_syscall_common() at fast_syscall_common+0xf8
    --- syscall (54, FreeBSD ELF64, sys_ioctl)
    
    MFC after:      1 week
    Reviewed by:    manu
    Reported by:    Graham Perrin <grahamperrin_AT_gmail_DOT_com>
    PR:             261166
    Differential Revision:  https://reviews.freebsd.org/D33888
---
 sys/compat/linuxkpi/common/src/linux_schedule.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sys/compat/linuxkpi/common/src/linux_schedule.c b/sys/compat/linuxkpi/common/src/linux_schedule.c
index 656d8697d169..02074be8eb19 100644
--- a/sys/compat/linuxkpi/common/src/linux_schedule.c
+++ b/sys/compat/linuxkpi/common/src/linux_schedule.c
@@ -202,9 +202,11 @@ void
 linux_wake_up(wait_queue_head_t *wqh, unsigned int state, int nr, bool locked)
 {
 	wait_queue_t *pos, *next;
+	unsigned long flags;
 
 	if (!locked)
-		spin_lock(&wqh->lock);
+		spin_lock_irqsave(&wqh->lock, flags);
+
 	list_for_each_entry_safe(pos, next, &wqh->task_list, task_list) {
 		if (pos->func == NULL) {
 			if (wake_up_task(pos->private, state) != 0 && --nr == 0)
@@ -215,7 +217,7 @@ linux_wake_up(wait_queue_head_t *wqh, unsigned int state, int nr, bool locked)
 		}
 	}
 	if (!locked)
-		spin_unlock(&wqh->lock);
+		spin_unlock_irqrestore(&wqh->lock, flags);
 }
 
 void