Author: attilio
Date: Mon Sep 7 08:52:15 2009
New Revision: 196915
URL: http://svn.freebsd.org/changeset/base/196915
Log:
MFC r195159 and r195005:
* Don't assume a fixed number of preloaded KLDs but calculate at runtime.
This avoind ending up into an endless loop.
* Fix a LOR between pmc_sx and allproc/proctree locks
Sponsored by: Sandvine Incorporated
Modified:
stable/7/sys/dev/hwpmc/hwpmc_logging.c
stable/7/sys/dev/hwpmc/hwpmc_mod.c
stable/7/sys/kern/kern_linker.c
Modified: stable/7/sys/dev/hwpmc/hwpmc_logging.c
==============================================================================
--- stable/7/sys/dev/hwpmc/hwpmc_logging.c Mon Sep 7 08:46:26 2009
(r196914)
+++ stable/7/sys/dev/hwpmc/hwpmc_logging.c Mon Sep 7 08:52:15 2009
(r196915)
@@ -44,6 +44,7 @@ __FBSDID("$FreeBSD$");
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/pmc.h>
+#include <sys/pmckern.h>
#include <sys/pmclog.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
@@ -552,6 +553,12 @@ pmclog_configure_log(struct pmc_mdep *md
int error;
struct proc *p;
+ /*
+ * As long as it is possible to get a LOR between pmc_sx lock and
+ * proctree/allproc sx locks used for adding a new process, assure
+ * the former is not held here.
+ */
+ sx_assert(&pmc_sx, SA_UNLOCKED);
PMCDBG(LOG,CFG,1, "config po=%p logfd=%d", po, logfd);
p = po->po_owner;
Modified: stable/7/sys/dev/hwpmc/hwpmc_mod.c
==============================================================================
--- stable/7/sys/dev/hwpmc/hwpmc_mod.c Mon Sep 7 08:46:26 2009
(r196914)
+++ stable/7/sys/dev/hwpmc/hwpmc_mod.c Mon Sep 7 08:52:15 2009
(r196915)
@@ -2666,7 +2666,7 @@ static const char *pmc_op_to_name[] = {
static int
pmc_syscall_handler(struct thread *td, void *syscall_args)
{
- int error, is_sx_downgraded, op;
+ int error, is_sx_downgraded, is_sx_locked, op;
struct pmc_syscall_args *c;
void *arg;
@@ -2675,6 +2675,7 @@ pmc_syscall_handler(struct thread *td, v
DROP_GIANT();
is_sx_downgraded = 0;
+ is_sx_locked = 1;
c = (struct pmc_syscall_args *) syscall_args;
@@ -2723,9 +2724,11 @@ pmc_syscall_handler(struct thread *td, v
* a log file configured, flush its buffers and
* de-configure it.
*/
- if (cl.pm_logfd >= 0)
+ if (cl.pm_logfd >= 0) {
+ sx_xunlock(&pmc_sx);
+ is_sx_locked = 0;
error = pmclog_configure_log(md, po, cl.pm_logfd);
- else if (po->po_flags & PMC_PO_OWNS_LOGFILE) {
+ } else if (po->po_flags & PMC_PO_OWNS_LOGFILE) {
pmclog_process_closelog(po);
error = pmclog_flush(po);
if (error == 0) {
@@ -3776,10 +3779,12 @@ pmc_syscall_handler(struct thread *td, v
break;
}
- if (is_sx_downgraded)
- sx_sunlock(&pmc_sx);
- else
- sx_xunlock(&pmc_sx);
+ if (is_sx_locked != 0) {
+ if (is_sx_downgraded)
+ sx_sunlock(&pmc_sx);
+ else
+ sx_xunlock(&pmc_sx);
+ }
if (error)
atomic_add_int(&pmc_stats.pm_syscall_errors, 1);
Modified: stable/7/sys/kern/kern_linker.c
==============================================================================
--- stable/7/sys/kern/kern_linker.c Mon Sep 7 08:46:26 2009
(r196914)
+++ stable/7/sys/kern/kern_linker.c Mon Sep 7 08:52:15 2009
(r196915)
@@ -1882,62 +1882,41 @@ linker_basename(const char *path)
}
#ifdef HWPMC_HOOKS
-
-struct hwpmc_context {
- int nobjects;
- int nmappings;
- struct pmckern_map_in *kobase;
-};
-
-static int
-linker_hwpmc_list_object(linker_file_t lf, void *arg)
-{
- struct hwpmc_context *hc;
-
- hc = arg;
-
- /* If we run out of mappings, fail. */
- if (hc->nobjects >= hc->nmappings)
- return (1);
-
- /* Save the info for this linker file. */
- hc->kobase[hc->nobjects].pm_file = lf->filename;
- hc->kobase[hc->nobjects].pm_address = (uintptr_t)lf->address;
- hc->nobjects++;
- return (0);
-}
-
/*
* Inform hwpmc about the set of kernel modules currently loaded.
*/
void *
linker_hwpmc_list_objects(void)
{
- struct hwpmc_context hc;
+ linker_file_t lf;
+ struct pmckern_map_in *kobase;
+ int i, nmappings;
- hc.nmappings = 15; /* a reasonable default */
+ nmappings = 0;
+ KLD_LOCK();
+ TAILQ_FOREACH(lf, &linker_files, link)
+ nmappings++;
- retry:
- /* allocate nmappings+1 entries */
- MALLOC(hc.kobase, struct pmckern_map_in *,
- (hc.nmappings + 1) * sizeof(struct pmckern_map_in), M_LINKER,
- M_WAITOK | M_ZERO);
-
- hc.nobjects = 0;
- if (linker_file_foreach(linker_hwpmc_list_object, &hc) != 0) {
- hc.nmappings = hc.nobjects;
- FREE(hc.kobase, M_LINKER);
- goto retry;
+ /* Allocate nmappings + 1 entries. */
+ kobase = malloc((nmappings + 1) * sizeof(struct pmckern_map_in),
+ M_LINKER, M_WAITOK | M_ZERO);
+ i = 0;
+ TAILQ_FOREACH(lf, &linker_files, link) {
+
+ /* Save the info for this linker file. */
+ kobase[i].pm_file = lf->filename;
+ kobase[i].pm_address = (uintptr_t)lf->address;
+ i++;
}
+ KLD_UNLOCK();
- KASSERT(hc.nobjects > 0, ("linker_hpwmc_list_objects: no kernel "
- "objects?"));
+ KASSERT(i > 0, ("linker_hwpmc_list_objects: no kernel objects?"));
/* The last entry of the malloced area comprises of all zeros. */
- KASSERT(hc.kobase[hc.nobjects].pm_file == NULL,
+ KASSERT(kobase[i].pm_file == NULL,
("linker_hwpmc_list_objects: last object not NULL"));
- return ((void *)hc.kobase);
+ return ((void *)kobase);
}
#endif
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