在 12/6/2019 9:46 PM, Jason Dillaman 写道:
On Fri, Dec 6, 2019 at 12:12 AM Dongsheng Yang
<dongsheng.yang@xxxxxxxxxxxx> wrote:
On 12/06/2019 12:50 PM, yangjun@xxxxxxxxxxxxxxxxxxxx wrote:
Hi Jason, dongsheng
I found a problem using rbd_open_by_id when connection timeout(errno = 110, ceph version 12.2.8, there is no change about rbd_open_by_id in master branch).
int r = ictx->state->open(false);
if (r < 0) { // r = -110
delete ictx; // crash，the stack is shown below：
} else {
*image = (rbd_image_t)ictx;
}
Stack is ：
(gdb) bt
Program terminated with signal 11, Segmentation fault.
#0 Mutex::Lock (this=this@entry=0x8, no_lockdep=no_lockdep@entry=false)
at /var/lib/jenkins/workspace/ceph_L/ceph/src/common/Mutex.cc:92
#1 0x0000ffff765eb814 in Locker (m=..., this=<synthetic pointer>)
at /var/lib/jenkins/workspace/ceph_L/ceph/src/common/Mutex.h:115
#2 PerfCountersCollection::remove (this=0x0, l=0xffff85bf0588 <main_arena+88>)
at /var/lib/jenkins/workspace/ceph_L/ceph/src/common/perf_counters.cc:62
#3 0x0000ffff757f26c4 in librbd::ImageCtx::perf_stop (this=0x2065d2f0)
at /var/lib/jenkins/workspace/ceph_L/ceph/src/librbd/ImageCtx.cc:426
#4 0x0000ffff757f6e48 in librbd::ImageCtx::~ImageCtx (this=0x2065d2f0, __in_chrg=<optimized out>)
at /var/lib/jenkins/workspace/ceph_L/ceph/src/librbd/ImageCtx.cc:239
#5 0x0000ffff757e8e70 in rbd_open_by_id (p=p@entry=0x2065e780,
id=id@entry=0xffff85928bb4 "20376aa706c0", image=image@entry=0xffff75b9b0b8,
snap_name=snap_name@entry=0x0) at /var/lib/jenkins/workspace/ceph_L/ceph/src/librbd/librbd.cc:2692
#6 0x0000ffff75aed524 in __pyx_pf_3rbd_5Image___init__ (
__pyx_v_read_only=0xffff85f02bb8 <_Py_ZeroStruct>, __pyx_v_snapshot=0xffff85f15938 <_Py_NoneStruct>,
__pyx_v_by_id=0xffff85f02ba0 <_Py_TrueStruct>, __pyx_v_name=0xffff85928b90,
__pyx_v_ioctx=0xffff7f0283d0, __pyx_v_self=0xffff75b9b0a8)
at /var/lib/jenkins/workspace/ceph_L/ceph/build/src/pybind/rbd/pyrex/rbd.c:12662
#7 __pyx_pw_3rbd_5Image_1__init__ (__pyx_v_self=0xffff75b9b0a8, __pyx_args=<optimized out>,
__pyx_kwds=<optimized out>)
at /var/lib/jenkins/workspace/ceph_L/ceph/build/src/pybind/rbd/pyrex/rbd.c:12378
#8 0x0000ffff85e02924 in type_call () from /lib64/libpython2.7.so.1.0
#9 0x0000ffff85dac254 in PyObject_Call () from /lib64/libpython2.7.so.1.0
I suspect you will hit tons of errors and corruption and leaking RADOS
objects when you start injecting RADOS timeouts. It's not something
librbd really supports or tests against -- so you need to expect the
unexpected. Definitely feel free to open a PR to fix it, though -- but
otherwise it would be a really *low* priority to fix.
Meanwhile, I have sone questions about rbd_open, if state->open failed（return value r < 0）, Is there a risk of memory leaks about ictx?
extern "C" int rbd_open(rados_ioctx_t p, const char *name, rbd_image_t *image,
const char *snap_name)
{
librados::IoCtx io_ctx;
librados::IoCtx::from_rados_ioctx_t(p, io_ctx);
TracepointProvider::initialize<tracepoint_traits>(get_cct(io_ctx));
librbd::ImageCtx *ictx = new librbd::ImageCtx(name, "", snap_name, io_ctx,
false);
tracepoint(librbd, open_image_enter, ictx, ictx->name.c_str(), ictx->id.c_str(), ictx->snap_name.c_str(), ictx->read_only);
int r = ictx->state->open(false);
if (r >= 0) { // if r < 0, Is there a risk of memory leaks?
Good catch. I think there is. And same at rbd_open_read_only. Seems we need a patch to fix them.
No, that's not a memory leak. The blocking version of
"ImageState::open" will free the "ImageCtx" memory upon failure.
My bad, I did not look it carefully before repling this mail,
I realized that we delete ctx in rbd_open_by_id but not in rbd_open, so
I thought it's a memory leak
in rbd_open. But I was wrong as you mentioned, it is released in
state->open(). So we dont need to add
a delete in rbd_open(), on the contrary, we need to remove the "delete
ictx" to avoid double-free problem as below:
diff --git a/src/librbd/librbd.cc b/src/librbd/librbd.cc
index 6c303c9..b518fad 100644
--- a/src/librbd/librbd.cc
+++ b/src/librbd/librbd.cc
@@ -3924,9 +3924,7 @@ extern "C" int rbd_open_by_id(rados_ioctx_t p,
const char *id,
ictx->id.c_str(), ictx->snap_name.c_str(), ictx->read_only);
int r = ictx->state->open(0);
- if (r < 0) {
- delete ictx;
- } else {
+ if (r >= 0) {
*image = (rbd_image_t)ictx;
}
tracepoint(librbd, open_image_exit, r);
@@ -3999,9 +3997,7 @@ extern "C" int
rbd_open_by_id_read_only(rados_ioctx_t p, const char *id,
ictx->id.c_str(), ictx->snap_name.c_str(), ictx->read_only);
int r = ictx->state->open(0);
- if (r < 0) {
- delete ictx;
- } else {
+ if (r >= 0) {
*image = (rbd_image_t)ictx;
}
tracepoint(librbd, open_image_exit, r);
There is a reproduce test.c attached.
Thanx
Yang
Thanx
Yang
*image = (rbd_image_t)ictx;
}
tracepoint(librbd, open_image_exit, r);
return r;
}
Can you give me some advice? many thanks.
________________________________
yangjun@xxxxxxxxxxxxxxxxxxxx
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <rados/librados.h>
#include <rbd/librbd.h>
int main(int argc, char** argv)
{
rados_t cluster;
char cluster_name[] = "ceph";
char user_name[] = "client.admin";
uint64_t flags = 0;
int i=0;
rados_ioctx_t io;
char *poolname = "rbd";
int rt_num;
rt_num = rados_create2(&cluster, cluster_name, user_name, flags);
if(rt_num < 0){
return -1;
}else{
printf("\nCreated a cluster handle success. \n");
}
rt_num = rados_conf_read_file(cluster, "/etc/ceph/ceph.conf");
if(rt_num < 0){
return -1;
}else{
printf("\nRead the config file. \n");
}
//Connect to the cluster
rt_num = rados_connect(cluster);
if(rt_num < 0){
return -1;
}else{
printf("\nConnected to the cluster.\n");
}
//create io handle
rt_num = rados_ioctx_create(cluster, poolname, &io);
if(rt_num<0){
rados_shutdown(cluster);
return -1;
}else{
printf("\nCreated I/O context. \n");
}
const char* id = "638de1bd4de892";
rbd_image_t image;
rt_num = rbd_open_by_id( io, id, &image, NULL);
if( rt_num ==0 ){
printf("\nrbd_open success !!\n");
}else{
printf("\nrbd_open failed !!%s\n", strerror(-rt_num));
rados_ioctx_destroy(io);
rados_shutdown(cluster);
return -1;
}
rt_num = rbd_close(image);
if(rt_num == 0){
printf("\nrbd_close success !!\n");
}else{
printf("\nrbd_close failed !!%s\n", strerror(-rt_num));
}
printf("\nClosing the connection\n");
rados_ioctx_destroy(io);
printf("\nShut down the handle\n");
rados_shutdown(cluster);
return 0;
}
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