diff options
| -rw-r--r-- | ChangeLog | 8 | ||||
| -rw-r--r-- | tapsets.cxx | 124 | ||||
| -rw-r--r-- | testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | testsuite/semko/maxactive04.stp | 5 | ||||
| -rw-r--r-- | testsuite/semko/maxactive05.stp | 5 |
5 files changed, 121 insertions, 26 deletions
@@ -1,3 +1,11 @@ +2008-01-26 Frank Ch. Eigler <fche@elastic.org> + + PR 5673. + * tapsets.cxx (dwarf_derived_probe_group): Split stap_dwarf_probes[] + into bss-carried kprobes structs. Tune embedded strings for + minimizing relocation-vs-fixed-buffer wastage. + * tapsets.cxx (dwarf_derived_probe): Impose .maxactive() limits. + 2008-01-25 Jim Keniston <jkenisto@us.ibm.com> * runtime/uprobes/uprobes.c: Within a probed process, serialize diff --git a/tapsets.cxx b/tapsets.cxx index 5b69373b..d753dc2e 100644 --- a/tapsets.cxx +++ b/tapsets.cxx @@ -3649,6 +3649,12 @@ dwarf_derived_probe::dwarf_derived_probe(const string& funcname, this->tok = q.base_probe->tok; + // Range limit maxactive() value + if (q.has_maxactive && (q.maxactive_val < 0 || q.maxactive_val > USHRT_MAX)) + throw semantic_error ("maxactive value out of range [0," + + lex_cast<string>(USHRT_MAX) + "]", + q.base_loc->tok); + // Make a target-variable-expanded copy of the probe body if (scope_die) { @@ -3810,16 +3816,61 @@ dwarf_derived_probe_group::emit_module_decls (systemtap_session& s) s.op->line() << " struct pt_regs *regs);"; // Emit the actual probe list. - s.op->newline() << "struct stap_dwarf_probe {"; + + // NB: we used to plop a union { struct kprobe; struct kretprobe } into + // struct stap_dwarf_probe, but it being initialized data makes it add + // hundreds of bytes of padding per stap_dwarf_probe. (PR5673) + s.op->newline() << "struct stap_dwarf_kprobe {"; s.op->newline(1) << "union { struct kprobe kp; struct kretprobe krp; } u;"; - s.op->newline() << "unsigned return_p:1;"; + s.op->newline(-1) << "} stap_dwarf_kprobes[" << probes_by_module.size() << "];"; + // NB: bss! + + s.op->newline() << "struct stap_dwarf_probe {"; + s.op->newline(1) << "unsigned return_p:1;"; s.op->newline() << "unsigned maxactive_p:1;"; s.op->newline() << "unsigned registered_p:1;"; - s.op->newline() << "const char *module;"; - s.op->newline() << "const char *section;"; + s.op->newline() << "unsigned short maxactive_val;"; + + // Let's find some stats for the three embedded strings. Maybe they + // are small and uniform enough to justify putting char[MAX]'s into + // the array instead of relocated char*'s. + size_t module_name_max = 0, section_name_max = 0, pp_name_max = 0; + size_t module_name_tot = 0, section_name_tot = 0, pp_name_tot = 0; + size_t all_name_cnt = probes_by_module.size(); // for average + for (p_b_m_iterator it = probes_by_module.begin(); it != probes_by_module.end(); it++) + { + dwarf_derived_probe* p = it->second; +#define DOIT(var,expr) do { \ + size_t var##_size = (expr) + 1; \ + var##_max = max (var##_max, var##_size); \ + var##_tot += var##_size; } while (0) + DOIT(module_name, p->module.size()); + DOIT(section_name, p->section.size()); + DOIT(pp_name, lex_cast_qstring(*p->sole_location()).size()); +#undef DOIT + } + + // Decide whether it's worthwhile to use char[] or char* by comparing + // the amount of average waste (max - avg) to the relocation data size + // (3 native long words). +#define CALCIT(var) \ + if ((var##_name_max-(var##_name_tot/all_name_cnt)) < (3 * sizeof(void*))) \ + { \ + s.op->newline() << "const char " << #var << "[" << var##_name_max << "];"; \ + if (s.verbose > 2) clog << "stap_dwarf_probe " << #var \ + << "[" << var##_name_max << "]" << endl; \ + } \ + else \ + { \ + s.op->newline() << "const char *" << #var << ";"; \ + if (s.verbose > 2) clog << "stap_dwarf_probe *" << #var << endl; \ + } + + CALCIT(module); + CALCIT(section); + CALCIT(pp); + s.op->newline() << "unsigned long address;"; - s.op->newline() << "unsigned long maxactive_val;"; - s.op->newline() << "const char *pp;"; s.op->newline() << "void (*ph) (struct context*);"; s.op->newline(-1) << "} stap_dwarf_probes[] = {"; s.op->indent(1); @@ -3831,12 +3882,14 @@ dwarf_derived_probe_group::emit_module_decls (systemtap_session& s) if (p->has_return) s.op->line() << " .return_p=1,"; if (p->has_maxactive) - s.op->line() << " .maxactive_p=1,"; + { + s.op->line() << " .maxactive_p=1,"; + assert (p->maxactive_val >= 0 && p->maxactive_val <= USHRT_MAX); + s.op->line() << " .maxactive_val=" << p->maxactive_val << ","; + } s.op->line() << " .address=0x" << hex << p->addr << dec << "UL,"; s.op->line() << " .module=\"" << p->module << "\","; s.op->line() << " .section=\"" << p->section << "\","; - if (p->has_maxactive) - s.op->line() << " .maxactive_val=" << p->maxactive_val << "UL,"; s.op->line() << " .pp=" << lex_cast_qstring (*p->sole_location()) << ","; s.op->line() << " .ph=&" << p->name; s.op->line() << " },"; @@ -3848,7 +3901,14 @@ dwarf_derived_probe_group::emit_module_decls (systemtap_session& s) s.op->newline(); s.op->newline() << "static int enter_kprobe_probe (struct kprobe *inst,"; s.op->line() << " struct pt_regs *regs) {"; - s.op->newline(1) << "struct stap_dwarf_probe *sdp = container_of(inst, struct stap_dwarf_probe, u.kp);"; + // NB: as of PR5673, the kprobe|kretprobe union struct is in BSS + s.op->newline(1) << "int kprobe_idx = ((uintptr_t)inst-(uintptr_t)stap_dwarf_kprobes)/sizeof(struct stap_dwarf_kprobe);"; + // Check that the index is plausible + s.op->newline() << "struct stap_dwarf_probe *sdp = &stap_dwarf_probes["; + s.op->line() << "((kprobe_idx >= 0 && kprobe_idx < " << probes_by_module.size() << ")?"; + s.op->line() << "kprobe_idx:0)"; // NB: at least we avoid memory corruption + // XXX: it would be nice to give a more verbose error though; BUG_ON later? + s.op->line() << "];"; common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING"); s.op->newline() << "c->probe_point = sdp->pp;"; s.op->newline() << "c->regs = regs;"; @@ -3862,7 +3922,16 @@ dwarf_derived_probe_group::emit_module_decls (systemtap_session& s) s.op->newline() << "static int enter_kretprobe_probe (struct kretprobe_instance *inst,"; s.op->line() << " struct pt_regs *regs) {"; s.op->newline(1) << "struct kretprobe *krp = inst->rp;"; - s.op->newline() << "struct stap_dwarf_probe *sdp = container_of(krp, struct stap_dwarf_probe, u.krp);"; + + // NB: as of PR5673, the kprobe|kretprobe union struct is in BSS + s.op->newline(1) << "int kprobe_idx = ((uintptr_t)krp-(uintptr_t)stap_dwarf_kprobes)/sizeof(struct stap_dwarf_kprobe);"; + // Check that the index is plausible + s.op->newline() << "struct stap_dwarf_probe *sdp = &stap_dwarf_probes["; + s.op->line() << "((kprobe_idx >= 0 && kprobe_idx < " << probes_by_module.size() << ")?"; + s.op->line() << "kprobe_idx:0)"; // NB: at least we avoid memory corruption + // XXX: it would be nice to give a more verbose error though; BUG_ON later? + s.op->line() << "];"; + common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING"); s.op->newline() << "c->probe_point = sdp->pp;"; s.op->newline() << "c->regs = regs;"; @@ -3879,28 +3948,30 @@ dwarf_derived_probe_group::emit_module_init (systemtap_session& s) { s.op->newline() << "for (i=0; i<" << probes_by_module.size() << "; i++) {"; s.op->newline(1) << "struct stap_dwarf_probe *sdp = & stap_dwarf_probes[i];"; + s.op->newline(1) << "struct stap_dwarf_kprobe *kp = & stap_dwarf_kprobes[i];"; s.op->newline() << "unsigned long relocated_addr = _stp_module_relocate (sdp->module, sdp->section, sdp->address);"; s.op->newline() << "if (relocated_addr == 0) continue;"; // quietly; assume module is absent s.op->newline() << "probe_point = sdp->pp;"; s.op->newline() << "if (sdp->return_p) {"; - s.op->newline(1) << "sdp->u.krp.kp.addr = (void *) relocated_addr;"; + s.op->newline(1) << "kp->u.krp.kp.addr = (void *) relocated_addr;"; s.op->newline() << "if (sdp->maxactive_p) {"; - s.op->newline(1) << "sdp->u.krp.maxactive = sdp->maxactive_val;"; + s.op->newline(1) << "kp->u.krp.maxactive = sdp->maxactive_val;"; s.op->newline(-1) << "} else {"; - s.op->newline(1) << "sdp->u.krp.maxactive = max(10, 4*NR_CPUS);"; + s.op->newline(1) << "kp->u.krp.maxactive = max(10, 4*NR_CPUS);"; s.op->newline(-1) << "}"; - s.op->newline() << "sdp->u.krp.handler = &enter_kretprobe_probe;"; - s.op->newline() << "rc = register_kretprobe (& sdp->u.krp);"; + s.op->newline() << "kp->u.krp.handler = &enter_kretprobe_probe;"; + s.op->newline() << "rc = register_kretprobe (& kp->u.krp);"; s.op->newline(-1) << "} else {"; - s.op->newline(1) << "sdp->u.kp.addr = (void *) relocated_addr;"; - s.op->newline() << "sdp->u.kp.pre_handler = &enter_kprobe_probe;"; - s.op->newline() << "rc = register_kprobe (& sdp->u.kp);"; + s.op->newline(1) << "kp->u.kp.addr = (void *) relocated_addr;"; + s.op->newline() << "kp->u.kp.pre_handler = &enter_kprobe_probe;"; + s.op->newline() << "rc = register_kprobe (& kp->u.kp);"; s.op->newline(-1) << "}"; s.op->newline() << "if (rc) {"; s.op->newline(1) << "for (j=i-1; j>=0; j--) {"; // partial rollback s.op->newline(1) << "struct stap_dwarf_probe *sdp2 = & stap_dwarf_probes[j];"; - s.op->newline() << "if (sdp2->return_p) unregister_kretprobe (&sdp2->u.krp);"; - s.op->newline() << "else unregister_kprobe (&sdp2->u.kp);"; + s.op->newline() << "struct stap_dwarf_kprobe *kp2 = & stap_dwarf_kprobes[j];"; + s.op->newline() << "if (sdp2->return_p) unregister_kretprobe (&kp2->u.krp);"; + s.op->newline() << "else unregister_kprobe (&kp2->u.kp);"; // NB: we don't have to clear sdp2->registered_p, since the module_exit code is // not run for this early-abort case. s.op->newline(-1) << "}"; @@ -3916,14 +3987,15 @@ dwarf_derived_probe_group::emit_module_exit (systemtap_session& s) { s.op->newline() << "for (i=0; i<" << probes_by_module.size() << "; i++) {"; s.op->newline(1) << "struct stap_dwarf_probe *sdp = & stap_dwarf_probes[i];"; + s.op->newline(1) << "struct stap_dwarf_kprobe *kp = & stap_dwarf_kprobes[i];"; s.op->newline() << "if (! sdp->registered_p) continue;"; s.op->newline() << "if (sdp->return_p) {"; - s.op->newline(1) << "unregister_kretprobe (&sdp->u.krp);"; - s.op->newline() << "atomic_add (sdp->u.krp.nmissed, & skipped_count);"; - s.op->newline() << "atomic_add (sdp->u.krp.kp.nmissed, & skipped_count);"; + s.op->newline(1) << "unregister_kretprobe (&kp->u.krp);"; + s.op->newline() << "atomic_add (kp->u.krp.nmissed, & skipped_count);"; + s.op->newline() << "atomic_add (kp->u.krp.kp.nmissed, & skipped_count);"; s.op->newline(-1) << "} else {"; - s.op->newline(1) << "unregister_kprobe (&sdp->u.kp);"; - s.op->newline() << "atomic_add (sdp->u.kp.nmissed, & skipped_count);"; + s.op->newline(1) << "unregister_kprobe (&kp->u.kp);"; + s.op->newline() << "atomic_add (kp->u.kp.nmissed, & skipped_count);"; s.op->newline(-1) << "}"; s.op->newline() << "sdp->registered_p = 0;"; s.op->newline(-1) << "}"; diff --git a/testsuite/ChangeLog b/testsuite/ChangeLog index c84c887e..4b5a3ce8 100644 --- a/testsuite/ChangeLog +++ b/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2008-01-26 Frank Ch. Eigler <fche@elastic.org> + + PR 5673. + * testsuite/parseko/maxactive{04,05}.stp: New tests. + 2008-01-24 Frank Ch. Eigler <fche@elastic.org> crash(8) tests, based on Masami Hiramatsu <mhiramat@redhat.com>: diff --git a/testsuite/semko/maxactive04.stp b/testsuite/semko/maxactive04.stp new file mode 100644 index 00000000..9471fd21 --- /dev/null +++ b/testsuite/semko/maxactive04.stp @@ -0,0 +1,5 @@ +#! stap -p2 + +probe kernel.function("sys_open").return.maxactive(-4) +{ +} diff --git a/testsuite/semko/maxactive05.stp b/testsuite/semko/maxactive05.stp new file mode 100644 index 00000000..bdc8a101 --- /dev/null +++ b/testsuite/semko/maxactive05.stp @@ -0,0 +1,5 @@ +#! stap -p2 + +probe kernel.function("sys_open").return.maxactive(99999999) +{ +} |