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Message-Id: <1431909055-21442-28-git-send-email-namhyung@kernel.org>
Date: Mon, 18 May 2015 09:30:42 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Jiri Olsa <jolsa@...hat.com>,
LKML <linux-kernel@...r.kernel.org>,
David Ahern <dsahern@...il.com>,
Adrian Hunter <adrian.hunter@...el.com>,
Andi Kleen <andi@...stfloor.org>,
Frederic Weisbecker <fweisbec@...il.com>,
Stephane Eranian <eranian@...gle.com>
Subject: [PATCH 27/40] perf tools: Protect dso cache fd with a mutex
When dso cache is accessed in multi-thread environment, it's possible
to close other dso->data.fd during operation due to open file limit.
Protect the file descriptors using a separate mutex.
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
tools/perf/util/dso.c | 98 +++++++++++++++++++++++++++++++++++++--------------
1 file changed, 72 insertions(+), 26 deletions(-)
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 425989e85302..8857287afc14 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -265,6 +265,7 @@ int __kmod_path__parse(struct kmod_path *m, const char *path,
*/
static LIST_HEAD(dso__data_open);
static long dso__data_open_cnt;
+static pthread_mutex_t dso__data_open_lock = PTHREAD_MUTEX_INITIALIZER;
static void dso__list_add(struct dso *dso)
{
@@ -434,7 +435,9 @@ static void check_data_close(void)
*/
void dso__data_close(struct dso *dso)
{
+ pthread_mutex_lock(&dso__data_open_lock);
close_dso(dso);
+ pthread_mutex_unlock(&dso__data_open_lock);
}
/**
@@ -457,6 +460,8 @@ int dso__data_fd(struct dso *dso, struct machine *machine)
if (dso->data.status == DSO_DATA_STATUS_ERROR)
return -1;
+ pthread_mutex_lock(&dso__data_open_lock);
+
if (dso->data.fd >= 0)
goto out;
@@ -479,6 +484,7 @@ int dso__data_fd(struct dso *dso, struct machine *machine)
else
dso->data.status = DSO_DATA_STATUS_ERROR;
+ pthread_mutex_unlock(&dso__data_open_lock);
return dso->data.fd;
}
@@ -583,7 +589,8 @@ dso_cache__memcpy(struct dso_cache *cache, u64 offset,
}
static ssize_t
-dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size)
+dso_cache__read(struct dso *dso, struct machine *machine,
+ u64 offset, u8 *data, ssize_t size)
{
struct dso_cache *cache;
struct dso_cache *old;
@@ -592,11 +599,24 @@ dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size)
do {
u64 cache_offset;
- ret = -ENOMEM;
-
cache = zalloc(sizeof(*cache) + DSO__DATA_CACHE_SIZE);
if (!cache)
- break;
+ return -ENOMEM;
+
+ pthread_mutex_lock(&dso__data_open_lock);
+
+ /*
+ * dso->data.fd might be closed if other thread opened another
+ * file (dso) due to open file limit (RLIMIT_NOFILE).
+ */
+ if (dso->data.fd < 0) {
+ dso->data.fd = open_dso(dso, machine);
+ if (dso->data.fd < 0) {
+ ret = -errno;
+ dso->data.status = DSO_DATA_STATUS_ERROR;
+ break;
+ }
+ }
cache_offset = offset & DSO__DATA_CACHE_MASK;
@@ -606,6 +626,11 @@ dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size)
cache->offset = cache_offset;
cache->size = ret;
+ } while (0);
+
+ pthread_mutex_unlock(&dso__data_open_lock);
+
+ if (ret > 0) {
old = dso_cache__insert(dso, cache);
if (old) {
/* we lose the race */
@@ -614,8 +639,7 @@ dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size)
}
ret = dso_cache__memcpy(cache, offset, data, size);
-
- } while (0);
+ }
if (ret <= 0)
free(cache);
@@ -623,8 +647,8 @@ dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size)
return ret;
}
-static ssize_t dso_cache_read(struct dso *dso, u64 offset,
- u8 *data, ssize_t size)
+static ssize_t dso_cache_read(struct dso *dso, struct machine *machine,
+ u64 offset, u8 *data, ssize_t size)
{
struct dso_cache *cache;
@@ -632,7 +656,7 @@ static ssize_t dso_cache_read(struct dso *dso, u64 offset,
if (cache)
return dso_cache__memcpy(cache, offset, data, size);
else
- return dso_cache__read(dso, offset, data, size);
+ return dso_cache__read(dso, machine, offset, data, size);
}
/*
@@ -640,7 +664,8 @@ static ssize_t dso_cache_read(struct dso *dso, u64 offset,
* in the rb_tree. Any read to already cached data is served
* by cached data.
*/
-static ssize_t cached_read(struct dso *dso, u64 offset, u8 *data, ssize_t size)
+static ssize_t cached_read(struct dso *dso, struct machine *machine,
+ u64 offset, u8 *data, ssize_t size)
{
ssize_t r = 0;
u8 *p = data;
@@ -648,7 +673,7 @@ static ssize_t cached_read(struct dso *dso, u64 offset, u8 *data, ssize_t size)
do {
ssize_t ret;
- ret = dso_cache_read(dso, offset, p, size);
+ ret = dso_cache_read(dso, machine, offset, p, size);
if (ret < 0)
return ret;
@@ -668,21 +693,42 @@ static ssize_t cached_read(struct dso *dso, u64 offset, u8 *data, ssize_t size)
return r;
}
-static int data_file_size(struct dso *dso)
+static int data_file_size(struct dso *dso, struct machine *machine)
{
+ int ret = 0;
struct stat st;
char sbuf[STRERR_BUFSIZE];
- if (!dso->data.file_size) {
- if (fstat(dso->data.fd, &st)) {
- pr_err("dso mmap failed, fstat: %s\n",
- strerror_r(errno, sbuf, sizeof(sbuf)));
- return -1;
+ if (dso->data.file_size)
+ return 0;
+
+ pthread_mutex_lock(&dso__data_open_lock);
+
+ /*
+ * dso->data.fd might be closed if other thread opened another
+ * file (dso) due to open file limit (RLIMIT_NOFILE).
+ */
+ if (dso->data.fd < 0) {
+ dso->data.fd = open_dso(dso, machine);
+ if (dso->data.fd < 0) {
+ ret = -errno;
+ dso->data.status = DSO_DATA_STATUS_ERROR;
+ goto out;
}
- dso->data.file_size = st.st_size;
}
- return 0;
+ if (fstat(dso->data.fd, &st) < 0) {
+ ret = -errno;
+ pr_err("dso cache fstat failed: %s\n",
+ strerror_r(errno, sbuf, sizeof(sbuf)));
+ dso->data.status = DSO_DATA_STATUS_ERROR;
+ goto out;
+ }
+ dso->data.file_size = st.st_size;
+
+out:
+ pthread_mutex_unlock(&dso__data_open_lock);
+ return ret;
}
/**
@@ -700,17 +746,17 @@ off_t dso__data_size(struct dso *dso, struct machine *machine)
if (fd < 0)
return fd;
- if (data_file_size(dso))
+ if (data_file_size(dso, machine))
return -1;
/* For now just estimate dso data size is close to file size */
return dso->data.file_size;
}
-static ssize_t data_read_offset(struct dso *dso, u64 offset,
- u8 *data, ssize_t size)
+static ssize_t data_read_offset(struct dso *dso, struct machine *machine,
+ u64 offset, u8 *data, ssize_t size)
{
- if (data_file_size(dso))
+ if (data_file_size(dso, machine))
return -1;
/* Check the offset sanity. */
@@ -720,7 +766,7 @@ static ssize_t data_read_offset(struct dso *dso, u64 offset,
if (offset + size < offset)
return -1;
- return cached_read(dso, offset, data, size);
+ return cached_read(dso, machine, offset, data, size);
}
/**
@@ -737,10 +783,10 @@ static ssize_t data_read_offset(struct dso *dso, u64 offset,
ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
u64 offset, u8 *data, ssize_t size)
{
- if (dso__data_fd(dso, machine) < 0)
+ if (dso->data.status == DSO_DATA_STATUS_ERROR)
return -1;
- return data_read_offset(dso, offset, data, size);
+ return data_read_offset(dso, machine, offset, data, size);
}
/**
--
2.4.0
--
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