This was spotted by Coverity, in case where sysconf(_SC_NPROCESSORS_ONLN)
fails and returns -1. This results in memset_num_threads getting set to -1.
Which we then pass to g_new0().
The patch replaces MAX_MEM_PREALLOC_THREAD_COUNT macro with a function call
get_memset_num_threads() to handle sysconf() failure gracefully. In case
sysconf() fails, we fall back to single threaded.
(Spotted by Coverity, CID 1372465.)
Signed-off-by: Jitendra Kolhe <jitendra.kolhe@hpe.com>
---
util/oslib-posix.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 3fe6089..4d9189e 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -55,7 +55,7 @@
#include "qemu/error-report.h"
#endif
-#define MAX_MEM_PREALLOC_THREAD_COUNT (MIN(sysconf(_SC_NPROCESSORS_ONLN), 16))
+#define MAX_MEM_PREALLOC_THREAD_COUNT 16
struct MemsetThread {
char *addr;
@@ -381,6 +381,18 @@ static void *do_touch_pages(void *arg)
return NULL;
}
+static inline int get_memset_num_threads(int smp_cpus)
+{
+ long host_procs = sysconf(_SC_NPROCESSORS_ONLN);
+ int ret = 1;
+
+ if (host_procs > 0) {
+ ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus);
+ }
+ /* In case sysconf() fails, we fall back to single threaded */
+ return ret;
+}
+
static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages,
int smp_cpus)
{
@@ -389,7 +401,7 @@ static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages,
int i = 0;
memset_thread_failed = false;
- memset_num_threads = MIN(smp_cpus, MAX_MEM_PREALLOC_THREAD_COUNT);
+ memset_num_threads = get_memset_num_threads(smp_cpus);
memset_thread = g_new0(MemsetThread, memset_num_threads);
numpages_per_thread = (numpages / memset_num_threads);
size_per_thread = (hpagesize * numpages_per_thread);
--
1.8.3.1
On 21/03/2017 07:50, Jitendra Kolhe wrote: > This was spotted by Coverity, in case where sysconf(_SC_NPROCESSORS_ONLN) > fails and returns -1. This results in memset_num_threads getting set to -1. > Which we then pass to g_new0(). > The patch replaces MAX_MEM_PREALLOC_THREAD_COUNT macro with a function call > get_memset_num_threads() to handle sysconf() failure gracefully. In case > sysconf() fails, we fall back to single threaded. > > (Spotted by Coverity, CID 1372465.) > > Signed-off-by: Jitendra Kolhe <jitendra.kolhe@hpe.com> > --- > util/oslib-posix.c | 16 ++++++++++++++-- > 1 file changed, 14 insertions(+), 2 deletions(-) > > diff --git a/util/oslib-posix.c b/util/oslib-posix.c > index 3fe6089..4d9189e 100644 > --- a/util/oslib-posix.c > +++ b/util/oslib-posix.c > @@ -55,7 +55,7 @@ > #include "qemu/error-report.h" > #endif > > -#define MAX_MEM_PREALLOC_THREAD_COUNT (MIN(sysconf(_SC_NPROCESSORS_ONLN), 16)) > +#define MAX_MEM_PREALLOC_THREAD_COUNT 16 > > struct MemsetThread { > char *addr; > @@ -381,6 +381,18 @@ static void *do_touch_pages(void *arg) > return NULL; > } > > +static inline int get_memset_num_threads(int smp_cpus) > +{ > + long host_procs = sysconf(_SC_NPROCESSORS_ONLN); > + int ret = 1; > + > + if (host_procs > 0) { > + ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus); > + } > + /* In case sysconf() fails, we fall back to single threaded */ > + return ret; > +} > + > static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages, > int smp_cpus) > { > @@ -389,7 +401,7 @@ static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages, > int i = 0; > > memset_thread_failed = false; > - memset_num_threads = MIN(smp_cpus, MAX_MEM_PREALLOC_THREAD_COUNT); > + memset_num_threads = get_memset_num_threads(smp_cpus); > memset_thread = g_new0(MemsetThread, memset_num_threads); > numpages_per_thread = (numpages / memset_num_threads); > size_per_thread = (hpagesize * numpages_per_thread); > Queued, thanks. Paolo
© 2016 - 2024 Red Hat, Inc.