static int stap_uprobe_change_plus (struct task_struct *tsk, unsigned long relocation, unsigned long length, const struct stap_uprobe_tf *stf, unsigned long offset, unsigned long vm_flags) {
int tfi = (stf - stap_uprobe_finders);
int spec_index;
/* iterate over stap_uprobe_spec[] that use this same stap_uprobe_tf */
for (spec_index=0; spec_index<sizeof(stap_uprobe_specs)/sizeof(stap_uprobe_specs[0]); spec_index++) {
int handled_p = 0;
int slotted_p = 0;
const struct stap_uprobe_spec *sups = &stap_uprobe_specs [spec_index];
struct stap_uprobe *sup;
pid_t sdt_sem_pid;
int rc = 0;
int i;
int pci;
if (likely(sups->tfi != tfi)) continue;
/* skip probes with an address beyond this map event; should not
happen unless a shlib/exec got mmapped in weirdly piecemeal */
if (likely((vm_flags & VM_EXEC) && sups->address >= length)) continue;
/* Found a uprobe_spec for this stap_uprobe_tf. Need to lock the
stap_uprobes[] array to allocate a free spot, but then we can
unlock and do the register_*probe subsequently. */
mutex_lock (& stap_uprobes_lock);
for (i=0; i<MAXUPROBES; i++) { /* XXX: slow linear search */
sup = & stap_uprobes[i];
/* register new uprobe
We make two passes for semaphores;
see stap_uprobe_change_semaphore_plus */
if (sup->spec_index < 0 || (sups->sdt_sem_offset && vm_flags & VM_WRITE && sup->spec_index == spec_index)) {
#if (UPROBES_API_VERSION < 2)
/* See PR6829 comment. */
if (sup->spec_index == -1 && sup->up.kdata != NULL) continue;
else if (sup->spec_index == -2 && sup->urp.u.kdata != NULL) continue;
#endif
sup->spec_index = spec_index;
slotted_p = 1;
break;
}
}
mutex_unlock (& stap_uprobes_lock);
#ifdef DEBUG_UPROBES
_stp_dbug(__FUNCTION__,__LINE__, "+uprobe spec %d idx %d process %s[%d] addr %p pp %s\n", spec_index, (slotted_p ? i : -1), tsk->comm, tsk->tgid, (void*)(relocation+sups->address), sups->probe->pp);
#endif
/* NB: check for user-module build-id only if we have a pathname
at all; for a process(PID#).* probe, we may not. If at some
point we map process(PID#) to process("/proc/PID#/exe"), we'll
get a pathname. */
if (stf->pathname)
if ((rc = _stp_usermodule_check(tsk, stf->pathname, relocation)))
return rc;
/* Here, slotted_p implies that `i' points to the single
stap_uprobes[] element that has been slotted in for registration
or unregistration processing. !slotted_p implies that the table
was full (registration; MAXUPROBES) or that no matching entry was
found (unregistration; should not happen). */
sdt_sem_pid = (sups->return_p ? sup->urp.u.pid : sup->up.pid);
if (sups->sdt_sem_offset && (sdt_sem_pid != tsk->tgid || sup->sdt_sem_address == 0)) {
/* If the probe is in an ET_EXEC binary, then the sdt_sem_offset already
* is a real address. But stap_uprobe_process_found calls us in this
* case with relocation=offset=0, so we don't have to worry about it. */
sup->sdt_sem_address = (relocation - offset) + sups->sdt_sem_offset;
} /* sdt_sem_offset */
for (pci=0; pci < sups->perf_counters_dim; pci++) {
if ((sups->perf_counters)[pci] > -1)
_stp_perf_read_init ((sups->perf_counters)[pci], tsk);
}
if (slotted_p) {
struct stap_uprobe *sup = & stap_uprobes[i];
if (sups->return_p) {
sup->urp.u.pid = tsk->tgid;
sup->urp.u.vaddr = relocation + sups->address;
sup->urp.handler = &enter_uretprobe_probe;
rc = register_uretprobe (& sup->urp);
} else {
sup->up.pid = tsk->tgid;
sup->up.vaddr = relocation + sups->address;
sup->up.handler = &enter_uprobe_probe;
rc = register_uprobe (& sup->up);
}
/* The u*probe failed to register. However, if we got EEXIST,
* that means that the u*probe is already there, so just ignore
* the error. This could happen if CLONE_THREAD or CLONE_VM was
* used. */
if (rc != 0 && rc != -EEXIST) {
_stp_warn ("u*probe failed %s[%d] '%s' addr %p rc %d\n", tsk->comm, tsk->tgid, sups->probe->pp, (void*)(relocation + sups->address), rc);
/* NB: we need to release this slot,
so we need to borrow the mutex temporarily. */
mutex_lock (& stap_uprobes_lock);
sup->spec_index = -1;
sup->sdt_sem_address = 0;
mutex_unlock (& stap_uprobes_lock);
} else {
handled_p = 1;
}
}
/* NB: handled_p implies slotted_p */
if (unlikely (! handled_p)) {
#ifdef STP_TIMING
atomic_inc (skipped_count_uprobe_reg());
#endif
/* NB: duplicates common_entryfn_epilogue,
but then this is not a probe entry fn epilogue. */
#ifndef STAP_SUPPRESS_HANDLER_ERRORS
if (unlikely (atomic_inc_return (skipped_count()) > MAXSKIPPED)) {
if (unlikely (pseudo_atomic_cmpxchg(session_state(), STAP_SESSION_RUNNING, STAP_SESSION_ERROR) == STAP_SESSION_RUNNING))
_stp_error ("Skipped too many probes, check MAXSKIPPED or try again with stap -t for more details.");
}
#endif
}
} /* close iteration over stap_uprobe_spec[] */
return 0; /* XXX: or rc? */
}
static int stap_uprobe_change_plus (struct task_struct *tsk, unsigned long relocation, unsigned long length, const struct stap_uprobe_tf *stf, unsigned long offset, unsigned long vm_flags) {
int tfi = (stf - stap_uprobe_finders);
int spec_index;
/* iterate over stap_uprobe_spec[] that use this same stap_uprobe_tf */
for (spec_index=0; spec_index<sizeof(stap_uprobe_specs)/sizeof(stap_uprobe_specs[0]); spec_index++) {
int handled_p = 0;
int slotted_p = 0;
const struct stap_uprobe_spec *sups = &stap_uprobe_specs [spec_index];
struct stap_uprobe *sup;
pid_t sdt_sem_pid;
int rc = 0;
int i;
if (likely(sups->tfi != tfi)) continue;
/* skip probes with an address beyond this map event; should not
happen unless a shlib/exec got mmapped in weirdly piecemeal */
if (likely((vm_flags & VM_EXEC) && sups->address >= length)) continue;
/* Found a uprobe_spec for this stap_uprobe_tf. Need to lock the
stap_uprobes[] array to allocate a free spot, but then we can
unlock and do the register_*probe subsequently. */
mutex_lock (& stap_uprobes_lock);
for (i=0; i<MAXUPROBES; i++) { /* XXX: slow linear search */
sup = & stap_uprobes[i];
/* register new uprobe
We make two passes for semaphores;
see _stap_uprobe_change_semaphore_plus */
if (sup->spec_index < 0 || (sups->sdt_sem_offset && vm_flags & VM_WRITE && sup->spec_index == spec_index)) {
#if (UPROBES_API_VERSION < 2)
/* See PR6829 comment. */
if (sup->spec_index == -1 && sup->up.kdata != NULL) continue;
else if (sup->spec_index == -2 && sup->urp.u.kdata != NULL) continue;
#endif
sup->spec_index = spec_index;
slotted_p = 1;
break;
}
}
mutex_unlock (& stap_uprobes_lock);
#ifdef DEBUG_UPROBES
_stp_dbug(__FUNCTION__,__LINE__, "+uprobe spec %d idx %d process %s[%d] addr %p pp %s\n", spec_index, (slotted_p ? i : -1), tsk->comm, tsk->tgid, (void*)(relocation+sups->address), sups->probe.pp);
#endif
/* Here, slotted_p implies that `i' points to the single
stap_uprobes[] element that has been slotted in for registration
or unregistration processing. !slotted_p implies that the table
was full (registration; MAXUPROBES) or that no matching entry was
found (unregistration; should not happen). */
sdt_sem_pid = (sups->return_p ? sup->urp.u.pid : sup->up.pid);
if (sups->sdt_sem_offset && (sdt_sem_pid != tsk->tgid || sup->sdt_sem_address == 0)) {
/* If the probe is in the executable itself, the offset *is* the address. */
if (vm_flags & VM_EXECUTABLE) {
sup->sdt_sem_address = relocation + sups->sdt_sem_offset;
}
else {
sup->sdt_sem_address = (relocation - offset) + sups->sdt_sem_offset;
}
} /* sdt_sem_offset */
if (slotted_p) {
struct stap_uprobe *sup = & stap_uprobes[i];
if (sups->return_p) {
sup->urp.u.pid = tsk->tgid;
sup->urp.u.vaddr = relocation + sups->address;
sup->urp.handler = &enter_uretprobe_probe;
rc = register_uretprobe (& sup->urp);
} else {
sup->up.pid = tsk->tgid;
sup->up.vaddr = relocation + sups->address;
sup->up.handler = &enter_uprobe_probe;
rc = register_uprobe (& sup->up);
}
if (rc) { /* failed to register */
_stp_warn ("u*probe failed %s[%d] '%s' addr %p rc %d\n", tsk->comm, tsk->tgid, sups->probe.pp, (void*)(relocation + sups->address), rc);
/* NB: we need to release this slot,
so we need to borrow the mutex temporarily. */
mutex_lock (& stap_uprobes_lock);
sup->spec_index = -1;
mutex_unlock (& stap_uprobes_lock);
} else {
handled_p = 1;
}
}
/* NB: handled_p implies slotted_p */
if (unlikely (! handled_p)) {
#ifdef STP_TIMING
atomic_inc (& skipped_count_uprobe_reg);
#endif
/* NB: duplicates common_entryfn_epilogue,
but then this is not a probe entry fn epilogue. */
if (unlikely (atomic_inc_return (& skipped_count) > MAXSKIPPED)) {
if (unlikely (pseudo_atomic_cmpxchg(& session_state, STAP_SESSION_RUNNING, STAP_SESSION_ERROR) == STAP_SESSION_RUNNING))
_stp_error ("Skipped too many probes, check MAXSKIPPED or try again with stap -t for more details.");
}
}
} /* close iteration over stap_uprobe_spec[] */
return 0; /* XXX: or rc? */
}
