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author | markj <markj@FreeBSD.org> | 2013-12-18 01:41:52 +0000 |
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committer | markj <markj@FreeBSD.org> | 2013-12-18 01:41:52 +0000 |
commit | fa6de9117d010d474939e5689c1d076d4918025b (patch) | |
tree | 6e1d82eccf41beda77ba33807668e571167cca32 /sys/cddl | |
parent | 2d61a75a7fed2c8b1a1480a43d3db460939839e1 (diff) | |
download | FreeBSD-src-fa6de9117d010d474939e5689c1d076d4918025b.zip FreeBSD-src-fa6de9117d010d474939e5689c1d076d4918025b.tar.gz |
The fasttrap fork handler is responsible for removing tracepoints in the
child process that were inherited from its parent. However, this should
not be done in the case of a vfork, since the fork handler ends up removing
the tracepoints from the shared vm space, and userland DTrace probes in the
parent will no longer fire as a result.
Now the child of a vfork may trigger userland DTrace probes enabled in its
parent, so modify the fasttrap probe handler to handle this case and handle
the child process in the same way that it would handle the traced process.
In particular, if once traces function foo() in a process that vforks, and
the child calls foo(), fasttrap will treat this call as having come from the
parent. This is the behaviour of the upstream code.
While here, add #ifdef guards to some code that isn't present upstream.
MFC after: 1 month
Diffstat (limited to 'sys/cddl')
-rw-r--r-- | sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c b/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c index c803a01..53ad33b 100644 --- a/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c +++ b/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c @@ -1001,6 +1001,9 @@ int fasttrap_pid_probe(struct reg *rp) { proc_t *p = curproc; +#if !defined(sun) + proc_t *pp; +#endif uintptr_t pc = rp->r_rip - 1; uintptr_t new_pc = 0; fasttrap_bucket_t *bucket; @@ -1036,24 +1039,32 @@ fasttrap_pid_probe(struct reg *rp) curthread->t_dtrace_regv = 0; #endif -#if defined(sun) /* * Treat a child created by a call to vfork(2) as if it were its * parent. We know that there's only one thread of control in such a * process: this one. */ +#if defined(sun) while (p->p_flag & SVFORK) { p = p->p_parent; } -#endif - PROC_LOCK(p); - _PHOLD(p); pid = p->p_pid; -#if defined(sun) pid_mtx = &cpu_core[CPU->cpu_id].cpuc_pid_lock; mutex_enter(pid_mtx); +#else + pp = p; + sx_slock(&proctree_lock); + while (pp->p_vmspace == pp->p_pptr->p_vmspace) + pp = pp->p_pptr; + pid = pp->p_pid; + sx_sunlock(&proctree_lock); + pp = NULL; + + PROC_LOCK(p); + _PHOLD(p); #endif + bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)]; /* @@ -1073,9 +1084,10 @@ fasttrap_pid_probe(struct reg *rp) if (tp == NULL) { #if defined(sun) mutex_exit(pid_mtx); -#endif +#else _PRELE(p); PROC_UNLOCK(p); +#endif return (-1); } @@ -1197,9 +1209,10 @@ fasttrap_pid_probe(struct reg *rp) * tracepoint again later if we need to light up any return probes. */ tp_local = *tp; - PROC_UNLOCK(p); #if defined(sun) mutex_exit(pid_mtx); +#else + PROC_UNLOCK(p); #endif tp = &tp_local; @@ -1749,7 +1762,7 @@ fasttrap_pid_probe(struct reg *rp) #if defined(sun) if (fasttrap_copyout(scratch, (char *)addr, i)) { #else - if (uwrite(curproc, scratch, i, addr)) { + if (uwrite(p, scratch, i, addr)) { #endif fasttrap_sigtrap(p, curthread, pc); new_pc = pc; @@ -1808,10 +1821,12 @@ done: rp->r_rip = new_pc; +#if !defined(sun) PROC_LOCK(p); proc_write_regs(curthread, rp); _PRELE(p); PROC_UNLOCK(p); +#endif return (0); } |