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. Reviewed by: rpaulo MFC after: 3 weeks
This commit is contained in:
parent
0d8243cc34
commit
3e0ba3a163
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=263329
@ -192,6 +192,9 @@ SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW,
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void
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trap(struct trapframe *frame)
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{
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#ifdef KDTRACE_HOOKS
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struct reg regs;
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#endif
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struct thread *td = curthread;
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struct proc *p = td->td_proc;
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int i = 0, ucode = 0, code;
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@ -243,28 +246,10 @@ trap(struct trapframe *frame)
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/*
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* A trap can occur while DTrace executes a probe. Before
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* executing the probe, DTrace blocks re-scheduling and sets
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* a flag in it's per-cpu flags to indicate that it doesn't
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* a flag in its per-cpu flags to indicate that it doesn't
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* want to fault. On returning from the probe, the no-fault
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* flag is cleared and finally re-scheduling is enabled.
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*
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* If the DTrace kernel module has registered a trap handler,
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* call it and if it returns non-zero, assume that it has
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* handled the trap and modified the trap frame so that this
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* function can return normally.
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*/
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if (type == T_DTRACE_RET || type == T_BPTFLT) {
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struct reg regs;
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fill_frame_regs(frame, ®s);
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if (type == T_BPTFLT &&
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dtrace_pid_probe_ptr != NULL &&
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dtrace_pid_probe_ptr(®s) == 0)
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goto out;
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else if (type == T_DTRACE_RET &&
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dtrace_return_probe_ptr != NULL &&
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dtrace_return_probe_ptr(®s) == 0)
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goto out;
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}
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if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
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goto out;
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#endif
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@ -319,6 +304,14 @@ trap(struct trapframe *frame)
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case T_BPTFLT: /* bpt instruction fault */
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case T_TRCTRAP: /* trace trap */
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enable_intr();
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#ifdef KDTRACE_HOOKS
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if (type == T_BPTFLT) {
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fill_frame_regs(frame, ®s);
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if (dtrace_pid_probe_ptr != NULL &&
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dtrace_pid_probe_ptr(®s) == 0)
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goto out;
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}
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#endif
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frame->tf_rflags &= ~PSL_T;
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i = SIGTRAP;
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ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
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@ -444,6 +437,15 @@ trap(struct trapframe *frame)
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goto userout;
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i = SIGFPE;
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break;
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#ifdef KDTRACE_HOOKS
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case T_DTRACE_RET:
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enable_intr();
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fill_frame_regs(frame, ®s);
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if (dtrace_return_probe_ptr != NULL &&
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dtrace_return_probe_ptr(®s) == 0)
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goto out;
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break;
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#endif
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}
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} else {
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/* kernel trap */
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@ -206,6 +206,9 @@ SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW,
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void
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trap(struct trapframe *frame)
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{
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#ifdef KDTRACE_HOOKS
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struct reg regs;
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#endif
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struct thread *td = curthread;
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struct proc *p = td->td_proc;
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int i = 0, ucode = 0, code;
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@ -262,28 +265,10 @@ trap(struct trapframe *frame)
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/*
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* A trap can occur while DTrace executes a probe. Before
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* executing the probe, DTrace blocks re-scheduling and sets
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* a flag in it's per-cpu flags to indicate that it doesn't
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* a flag in its per-cpu flags to indicate that it doesn't
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* want to fault. On returning from the probe, the no-fault
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* flag is cleared and finally re-scheduling is enabled.
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*
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* If the DTrace kernel module has registered a trap handler,
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* call it and if it returns non-zero, assume that it has
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* handled the trap and modified the trap frame so that this
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* function can return normally.
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*/
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if (type == T_DTRACE_RET || type == T_BPTFLT) {
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struct reg regs;
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fill_frame_regs(frame, ®s);
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if (type == T_BPTFLT &&
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dtrace_pid_probe_ptr != NULL &&
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dtrace_pid_probe_ptr(®s) == 0)
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goto out;
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if (type == T_DTRACE_RET &&
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dtrace_return_probe_ptr != NULL &&
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dtrace_return_probe_ptr(®s) == 0)
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goto out;
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}
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if ((type == T_PROTFLT || type == T_PAGEFLT) &&
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dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
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goto out;
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@ -357,6 +342,14 @@ trap(struct trapframe *frame)
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case T_BPTFLT: /* bpt instruction fault */
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case T_TRCTRAP: /* trace trap */
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enable_intr();
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#ifdef KDTRACE_HOOKS
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if (type == T_BPTFLT) {
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fill_frame_regs(frame, ®s);
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if (dtrace_pid_probe_ptr != NULL &&
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dtrace_pid_probe_ptr(®s) == 0)
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goto out;
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}
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#endif
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frame->tf_eflags &= ~PSL_T;
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i = SIGTRAP;
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ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
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@ -536,6 +529,15 @@ trap(struct trapframe *frame)
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#endif
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i = SIGFPE;
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break;
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#ifdef KDTRACE_HOOKS
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case T_DTRACE_RET:
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enable_intr();
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fill_frame_regs(frame, ®s);
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if (dtrace_return_probe_ptr != NULL &&
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dtrace_return_probe_ptr(®s) == 0)
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goto out;
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break;
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#endif
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}
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} else {
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/* kernel trap */
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