git: c589d6a09f5e - stable/15 - buf: Relax an assertion in BUF_UNLOCK

The branch stable/15 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=c589d6a09f5ec9096784d14a4a0fb136ea3de208

commit c589d6a09f5ec9096784d14a4a0fb136ea3de208
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2026-02-22 19:26:17 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2026-03-31 15:57:29 +0000

    buf: Relax an assertion in BUF_UNLOCK
    
    The BUF_UNLOCK macro asserts that B_REMFREE is not set, as it is up to
    the lock owner to complete the dequeue from the free list before
    releasing the lock.  However, if the thread has acquired the lock
    multiple times, then releasing the recursive lock should be ok.  Modify
    the assertion to reflect this.
    
    This was triggered by an out-of-tree filesystem.
    
    Reviewed by:    kib
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D55418
    
    (cherry picked from commit eaeb356ce3491f05b6a99ccd485180a42df22c46)
---
 sys/sys/buf.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/sys/buf.h b/sys/sys/buf.h
index f08f05e6d50f..85ff5f3dfdc1 100644
--- a/sys/sys/buf.h
+++ b/sys/sys/buf.h
@@ -321,7 +321,7 @@ struct buf {
  * it has been handed off to biodone.
  */
 #define	BUF_UNLOCK(bp) do {						\
-	KASSERT(((bp)->b_flags & B_REMFREE) == 0,			\
+	KASSERT(((bp)->b_flags & B_REMFREE) == 0 || BUF_LOCKRECURSED(bp), \
 	    ("BUF_UNLOCK %p while B_REMFREE is still set.", (bp)));	\
 									\
 	BUF_UNLOCK_RAW((bp));						\