git: 02d90458669d - main - tslog: Handle curthread equal to NULL

The branch main has been updated by cperciva:

URL: https://cgit.FreeBSD.org/src/commit/?id=02d90458669d6f8063ef32e35069e9246f487b37

commit 02d90458669d6f8063ef32e35069e9246f487b37
Author:     Colin Percival <cperciva@FreeBSD.org>
AuthorDate: 2023-05-21 20:03:33 +0000
Commit:     Colin Percival <cperciva@FreeBSD.org>
CommitDate: 2023-06-04 17:16:22 +0000

    tslog: Handle curthread equal to NULL
    
    Early in the kernel boot, curthread goes through three stages:
    
    1. Kernel crash when you try to access it, because PCPU doesn't exist.
    2. NULL, because PCU exists but isn't initialized.
    3. &thread0, which is where most of the kernel boot process runs.
    
    This broke TSLOG from inside hammer_time since the scripts which parse
    logged records didn't understand that NULL meant &thread0.
    
    Tell tslog to record &thread0 as the active thread if passed NULL.
    
    Sponsored by:   https://www.patreon.com/cperciva
    Differential Revision:  https://reviews.freebsd.org/D40324
---
 sys/kern/kern_tslog.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/kern/kern_tslog.c b/sys/kern/kern_tslog.c
index 5eba7719880d..3629f7d88a93 100644
--- a/sys/kern/kern_tslog.c
+++ b/sys/kern/kern_tslog.c
@@ -59,6 +59,10 @@ tslog(void * td, int type, const char * f, const char * s)
 	uint64_t tsc = get_cyclecount();
 	long pos;
 
+	/* A NULL thread is thread0 before curthread is set. */
+	if (td == NULL)
+		td = &thread0;
+
 	/* Grab a slot. */
 	pos = atomic_fetchadd_long(&nrecs, 1);