Author: markj
Date: Tue Jul 29 20:33:18 2014
New Revision: 269253
URL: http://svnweb.freebsd.org/changeset/base/269253
Log:
MFC r263329:
Only invoke fasttrap hooks for traps from user mode, and ensure that they're
called with interrupts enabled. Calling fasttrap_pid_probe() with interrupts
disabled can lead to deadlock if fasttrap writes to the process' address
space.
Modified:
stable/10/sys/amd64/amd64/trap.c
stable/10/sys/i386/i386/trap.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/amd64/amd64/trap.c
==============================================================================
--- stable/10/sys/amd64/amd64/trap.c Tue Jul 29 19:49:38 2014
(r269252)
+++ stable/10/sys/amd64/amd64/trap.c Tue Jul 29 20:33:18 2014
(r269253)
@@ -193,6 +193,9 @@ SYSCTL_INT(_machdep, OID_AUTO, uprintf_s
void
trap(struct trapframe *frame)
{
+#ifdef KDTRACE_HOOKS
+ struct reg regs;
+#endif
struct thread *td = curthread;
struct proc *p = td->td_proc;
int i = 0, ucode = 0, code;
@@ -244,28 +247,10 @@ trap(struct trapframe *frame)
/*
* A trap can occur while DTrace executes a probe. Before
* executing the probe, DTrace blocks re-scheduling and sets
- * a flag in it's per-cpu flags to indicate that it doesn't
+ * a flag in its per-cpu flags to indicate that it doesn't
* want to fault. On returning from the probe, the no-fault
* flag is cleared and finally re-scheduling is enabled.
- *
- * If the DTrace kernel module has registered a trap handler,
- * call it and if it returns non-zero, assume that it has
- * handled the trap and modified the trap frame so that this
- * function can return normally.
*/
- if (type == T_DTRACE_RET || type == T_BPTFLT) {
- struct reg regs;
-
- fill_frame_regs(frame, ®s);
- if (type == T_BPTFLT &&
- dtrace_pid_probe_ptr != NULL &&
- dtrace_pid_probe_ptr(®s) == 0)
- goto out;
- else if (type == T_DTRACE_RET &&
- dtrace_return_probe_ptr != NULL &&
- dtrace_return_probe_ptr(®s) == 0)
- goto out;
- }
if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
goto out;
#endif
@@ -320,6 +305,14 @@ trap(struct trapframe *frame)
case T_BPTFLT: /* bpt instruction fault */
case T_TRCTRAP: /* trace trap */
enable_intr();
+#ifdef KDTRACE_HOOKS
+ if (type == T_BPTFLT) {
+ fill_frame_regs(frame, ®s);
+ if (dtrace_pid_probe_ptr != NULL &&
+ dtrace_pid_probe_ptr(®s) == 0)
+ goto out;
+ }
+#endif
frame->tf_rflags &= ~PSL_T;
i = SIGTRAP;
ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
@@ -449,6 +442,15 @@ trap(struct trapframe *frame)
goto userout;
i = SIGFPE;
break;
+#ifdef KDTRACE_HOOKS
+ case T_DTRACE_RET:
+ enable_intr();
+ fill_frame_regs(frame, ®s);
+ if (dtrace_return_probe_ptr != NULL &&
+ dtrace_return_probe_ptr(®s) == 0)
+ goto out;
+ break;
+#endif
}
} else {
/* kernel trap */
Modified: stable/10/sys/i386/i386/trap.c
==============================================================================
--- stable/10/sys/i386/i386/trap.c Tue Jul 29 19:49:38 2014
(r269252)
+++ stable/10/sys/i386/i386/trap.c Tue Jul 29 20:33:18 2014
(r269253)
@@ -207,6 +207,9 @@ SYSCTL_INT(_machdep, OID_AUTO, uprintf_s
void
trap(struct trapframe *frame)
{
+#ifdef KDTRACE_HOOKS
+ struct reg regs;
+#endif
struct thread *td = curthread;
struct proc *p = td->td_proc;
int i = 0, ucode = 0, code;
@@ -263,28 +266,10 @@ trap(struct trapframe *frame)
/*
* A trap can occur while DTrace executes a probe. Before
* executing the probe, DTrace blocks re-scheduling and sets
- * a flag in it's per-cpu flags to indicate that it doesn't
+ * a flag in its per-cpu flags to indicate that it doesn't
* want to fault. On returning from the probe, the no-fault
* flag is cleared and finally re-scheduling is enabled.
- *
- * If the DTrace kernel module has registered a trap handler,
- * call it and if it returns non-zero, assume that it has
- * handled the trap and modified the trap frame so that this
- * function can return normally.
*/
- if (type == T_DTRACE_RET || type == T_BPTFLT) {
- struct reg regs;
-
- fill_frame_regs(frame, ®s);
- if (type == T_BPTFLT &&
- dtrace_pid_probe_ptr != NULL &&
- dtrace_pid_probe_ptr(®s) == 0)
- goto out;
- if (type == T_DTRACE_RET &&
- dtrace_return_probe_ptr != NULL &&
- dtrace_return_probe_ptr(®s) == 0)
- goto out;
- }
if ((type == T_PROTFLT || type == T_PAGEFLT) &&
dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
goto out;
@@ -358,6 +343,14 @@ trap(struct trapframe *frame)
case T_BPTFLT: /* bpt instruction fault */
case T_TRCTRAP: /* trace trap */
enable_intr();
+#ifdef KDTRACE_HOOKS
+ if (type == T_BPTFLT) {
+ fill_frame_regs(frame, ®s);
+ if (dtrace_pid_probe_ptr != NULL &&
+ dtrace_pid_probe_ptr(®s) == 0)
+ goto out;
+ }
+#endif
frame->tf_eflags &= ~PSL_T;
i = SIGTRAP;
ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
@@ -541,6 +534,15 @@ trap(struct trapframe *frame)
#endif
i = SIGFPE;
break;
+#ifdef KDTRACE_HOOKS
+ case T_DTRACE_RET:
+ enable_intr();
+ fill_frame_regs(frame, ®s);
+ if (dtrace_return_probe_ptr != NULL &&
+ dtrace_return_probe_ptr(®s) == 0)
+ goto out;
+ break;
+#endif
}
} else {
/* kernel trap */
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