diff options
author | markj <markj@FreeBSD.org> | 2014-03-19 01:27:56 +0000 |
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committer | markj <markj@FreeBSD.org> | 2014-03-19 01:27:56 +0000 |
commit | b41aca8e4d1667242ba798bec20b2f33c06e1a72 (patch) | |
tree | eb985f620f7c3e91e7bb4226519993bdba9eef00 /sys/i386 | |
parent | f19bbde667a9348da3a87d8020cdcdd8e58f77d0 (diff) | |
download | FreeBSD-src-b41aca8e4d1667242ba798bec20b2f33c06e1a72.zip FreeBSD-src-b41aca8e4d1667242ba798bec20b2f33c06e1a72.tar.gz |
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
Diffstat (limited to 'sys/i386')
-rw-r--r-- | sys/i386/i386/trap.c | 40 |
1 files changed, 21 insertions, 19 deletions
diff --git a/sys/i386/i386/trap.c b/sys/i386/i386/trap.c index 884e0f0..be76575 100644 --- a/sys/i386/i386/trap.c +++ b/sys/i386/i386/trap.c @@ -206,6 +206,9 @@ SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW, 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; @@ -262,28 +265,10 @@ 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; @@ -357,6 +342,14 @@ 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); @@ -536,6 +529,15 @@ 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 */ |