Author: gibbs
Date: Mon Mar 4 22:07:36 2013
New Revision: 247820
URL: http://svnweb.freebsd.org/changeset/base/247820
Log:
Fix assertion failure when using userland DTrace probes from
the pid provider on a kernel compiled with INVARIANTS.
sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c:
In fasttrap_probe_pid(), attempts to write to the
address space of the thread that fired the probe
must be performed with the process of the thread
held. Use _PHOLD() to ensure this is the case.
In fasttrap_probe_pid(), use proc_write_regs() instead
of calling set_regs() directly. proc_write_regs()
performs invariant checks to verify the calling
environment of set_regs(). PROC_LOCK()/UNLOCK() around
the call to proc_write_regs() so that it's invariants
are satisfied.
Sponsored by: Spectra Logic Corporation
Reviewed by: gnn, rpaulo
MFC after: 1 week
Modified:
head/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c
Modified: head/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c Mon Mar
4 22:04:14 2013 (r247819)
+++ head/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c Mon Mar
4 22:07:36 2013 (r247820)
@@ -1034,6 +1034,7 @@ fasttrap_pid_probe(struct reg *rp)
#endif
PROC_LOCK(p);
+ _PHOLD(p);
pid = p->p_pid;
#if defined(sun)
pid_mtx = &cpu_core[CPU->cpu_id].cpuc_pid_lock;
@@ -1059,6 +1060,7 @@ fasttrap_pid_probe(struct reg *rp)
#if defined(sun)
mutex_exit(pid_mtx);
#endif
+ _PRELE(p);
PROC_UNLOCK(p);
return (-1);
}
@@ -1732,7 +1734,6 @@ fasttrap_pid_probe(struct reg *rp)
ASSERT(i <= sizeof (scratch));
-
#if defined(sun)
if (fasttrap_copyout(scratch, (char *)addr, i)) {
#else
@@ -1794,7 +1795,11 @@ done:
}
rp->r_rip = new_pc;
- set_regs(curthread, rp);
+
+ PROC_LOCK(p);
+ proc_write_regs(curthread, rp);
+ _PRELE(p);
+ PROC_UNLOCK(p);
return (0);
}
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