Index: sys/sys/proc.h
===================================================================
--- sys/sys/proc.h	(wersja 243142)
+++ sys/sys/proc.h	(kopia robocza)
@@ -528,6 +528,7 @@
 	int		p_traceflag;	/* (o) Kernel trace points. */
 	struct vnode	*p_tracevp;	/* (c + o) Trace to vnode. */
 	struct ucred	*p_tracecred;	/* (o) Credentials to trace with. */
+	rlim_t		p_tracefsize;	/* (c) File size limit of the tracer. */
 	struct vnode	*p_textvp;	/* (b) Vnode of executable. */
 	u_int		p_lock;		/* (c) Proclock (prevent swap) count. */
 	struct sigiolst	p_sigiolst;	/* (c) List of sigio sources. */
Index: sys/kern/vfs_vnops.c
===================================================================
--- sys/kern/vfs_vnops.c	(wersja 243142)
+++ sys/kern/vfs_vnops.c	(kopia robocza)
@@ -1820,17 +1820,27 @@
 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio,
     const struct thread *td)
 {
+	struct proc *p;
+	rlim_t fsize;
 
 	if (vp->v_type != VREG || td == NULL)
 		return (0);
-	PROC_LOCK(td->td_proc);
-	if ((uoff_t)uio->uio_offset + uio->uio_resid >
-	    lim_cur(td->td_proc, RLIMIT_FSIZE)) {
-		kern_psignal(td->td_proc, SIGXFSZ);
-		PROC_UNLOCK(td->td_proc);
+	p = td->td_proc;
+	PROC_LOCK(p);
+	/*
+	 * If this is ktrace file, use fsize limit of the tracer, otherwise
+	 * use fsize limit of the process doing the write.
+	 */
+	if (vp == p->p_tracevp)
+		fsize = p->p_tracefsize;
+	else
+		fsize = lim_cur(p, RLIMIT_FSIZE);
+	if ((uoff_t)uio->uio_offset + uio->uio_resid > fsize) {
+		kern_psignal(p, SIGXFSZ);
+		PROC_UNLOCK(p);
 		return (EFBIG);
 	}
-	PROC_UNLOCK(td->td_proc);
+	PROC_UNLOCK(p);
 	return (0);
 }
 
Index: sys/kern/kern_ktrace.c
===================================================================
--- sys/kern/kern_ktrace.c	(wersja 243142)
+++ sys/kern/kern_ktrace.c	(kopia robocza)
@@ -583,6 +583,7 @@
 			KASSERT(p1->p_tracecred != NULL,
 			    ("ktrace vnode with no cred"));
 			p2->p_tracecred = crhold(p1->p_tracecred);
+			p2->p_tracefsize = p1->p_tracefsize;
 		}
 	}
 	mtx_unlock(&ktrace_mtx);
@@ -1059,6 +1060,9 @@
 		if (p->p_tracecred != td->td_ucred) {
 			tracecred = p->p_tracecred;
 			p->p_tracecred = crhold(td->td_ucred);
+			PROC_LOCK(td->td_proc);
+			p->p_tracefsize = lim_cur(td->td_proc, RLIMIT_FSIZE);
+			PROC_UNLOCK(td->td_proc);
 		}
 		p->p_traceflag |= facs;
 		if (priv_check(td, PRIV_KTRACE) == 0)