* question about rcu_bp_exit()
@ 2016-05-18 10:07 songxin
0 siblings, 0 replies; 5+ messages in thread
From: songxin @ 2016-05-18 10:07 UTC (permalink / raw)
To: lttng-dev
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Hi,
Now I get a crash because receiving signal SIGSEGV as below.
#0 arena_alloc (arena=<optimized out>) at /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:432
#1 add_thread () at /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:462
#2 rcu_bp_register () at /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:541
I read the code of urcu-bp.c and found that "if (chunk->data_len - chunk->used < len)" is in 432 line. So I guess that the chunk is a illegal pointer.
Below is the function rcu_bp_exit().
static
void rcu_bp_exit(void)
{
mutex_lock(&init_lock);
if (!--rcu_bp_refcount) {
struct registry_chunk *chunk, *tmp;
int ret;
cds_list_for_each_entry_safe(chunk, tmp,
®istry_arena.chunk_list, node) {
munmap(chunk, chunk->data_len
+ sizeof(struct registry_chunk));
}
ret = pthread_key_delete(urcu_bp_key);
if (ret)
abort();
}
mutex_unlock(&init_lock);
}
My question is below.
Why did not delete the chunk from registry_arena.chunk_list before munmap a chunk?
Thanks,
xin
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: question about rcu_bp_exit()
[not found] ` <971830834.12745.1463596803434.JavaMail.zimbra@efficios.com>
@ 2016-05-19 19:53 ` Paul E. McKenney
0 siblings, 0 replies; 5+ messages in thread
From: Paul E. McKenney @ 2016-05-19 19:53 UTC (permalink / raw)
To: Mathieu Desnoyers; +Cc: lttng-dev
On Wed, May 18, 2016 at 06:40:03PM +0000, Mathieu Desnoyers wrote:
> ----- On May 18, 2016, at 5:44 AM, songxin <songxin_1980@126.com> wrote:
>
> > Hi,
> > Now I get a crash because receiving signal SIGSEGV as below.
>
> > #0 arena_alloc (arena=<optimized out>) at
> > /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:432
> > #1 add_thread () at
> > /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:462
> > #2 rcu_bp_register () at
> > /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:541
>
> > I read the code of urcu-bp.c and found that "if (chunk->data_len - chunk->used <
> > len)" is in 432 line. So I guess that the chunk is a illegal pointer.
> > Below is the function rcu_bp_exit().
>
> > static
> > void rcu_bp_exit(void)
> > {
> > mutex_lock(&init_lock);
> > if (!--rcu_bp_refcount) {
> > struct registry_chunk *chunk, *tmp;
> > int ret;
>
> > cds_list_for_each_entry_safe(chunk, tmp,
> > ®istry_arena.chunk_list, node) {
> > munmap(chunk, chunk->data_len
> > + sizeof(struct registry_chunk));
> > }
> > ret = pthread_key_delete(urcu_bp_key);
> > if (ret)
> > abort();
> > }
> > mutex_unlock(&init_lock);
> > }
>
> > My question is below.
> > Why did not delete the chunk from registry_arena.chunk_list before munmap a
> > chunk?
>
> It is not expected that any thread would be created after the execution of
> rcu_bp_exit() as a library destructor. Does re-initializing the chunk_list after
> iterating on it within rcu_bp_exit() fix your issue ?
>
> I'm curious about your use-case for creating threads after the library destructor
> has run.
I am with Mathieu on this -- not much good can be expected using things
after their cleanup. Though I suppose that, given a sufficient use case,
there could at least in theory be an option for manual control of cleanup.
Thanx, Paul
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: question about rcu_bp_exit()
[not found] <6db07fb4.c6e5.154c340296f.Coremail.songxin_1980@126.com>
@ 2016-05-18 18:40 ` Mathieu Desnoyers
[not found] ` <971830834.12745.1463596803434.JavaMail.zimbra@efficios.com>
1 sibling, 0 replies; 5+ messages in thread
From: Mathieu Desnoyers @ 2016-05-18 18:40 UTC (permalink / raw)
To: songxin; +Cc: lttng-dev, Paul E. McKenney
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----- On May 18, 2016, at 5:44 AM, songxin <songxin_1980@126.com> wrote:
> Hi,
> Now I get a crash because receiving signal SIGSEGV as below.
> #0 arena_alloc (arena=<optimized out>) at
> /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:432
> #1 add_thread () at
> /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:462
> #2 rcu_bp_register () at
> /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:541
> I read the code of urcu-bp.c and found that "if (chunk->data_len - chunk->used <
> len)" is in 432 line. So I guess that the chunk is a illegal pointer.
> Below is the function rcu_bp_exit().
> static
> void rcu_bp_exit(void)
> {
> mutex_lock(&init_lock);
> if (!--rcu_bp_refcount) {
> struct registry_chunk *chunk, *tmp;
> int ret;
> cds_list_for_each_entry_safe(chunk, tmp,
> ®istry_arena.chunk_list, node) {
> munmap(chunk, chunk->data_len
> + sizeof(struct registry_chunk));
> }
> ret = pthread_key_delete(urcu_bp_key);
> if (ret)
> abort();
> }
> mutex_unlock(&init_lock);
> }
> My question is below.
> Why did not delete the chunk from registry_arena.chunk_list before munmap a
> chunk?
It is not expected that any thread would be created after the execution of
rcu_bp_exit() as a library destructor. Does re-initializing the chunk_list after
iterating on it within rcu_bp_exit() fix your issue ?
I'm curious about your use-case for creating threads after the library destructor
has run.
Thanks,
Mathieu
> Thanks,
> xin
> _______________________________________________
> lttng-dev mailing list
> lttng-dev@lists.lttng.org
> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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^ permalink raw reply [flat|nested] 5+ messages in thread
* question about rcu_bp_exit()
@ 2016-05-18 10:04 songxin
0 siblings, 0 replies; 5+ messages in thread
From: songxin @ 2016-05-18 10:04 UTC (permalink / raw)
To: lttng-dev
[-- Attachment #1.1: Type: text/plain, Size: 1372 bytes --]
Hi,
Now I get a crash because receiving signal SIGSEGV as below.
#0 arena_alloc (arena=<optimized out>) at /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:432
#1 add_thread () at /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:462
#2 rcu_bp_register () at /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:541
I read the code of urcu-bp.c and found that "if (chunk->data_len - chunk->used < len)" is in 432 line. So I guess that the chunk is a illegal pointer.
Below is the function rcu_bp_exit().
static
void rcu_bp_exit(void)
{
mutex_lock(&init_lock);
if (!--rcu_bp_refcount) {
struct registry_chunk *chunk, *tmp;
int ret;
cds_list_for_each_entry_safe(chunk, tmp,
®istry_arena.chunk_list, node) {
munmap(chunk, chunk->data_len
+ sizeof(struct registry_chunk));
}
ret = pthread_key_delete(urcu_bp_key);
if (ret)
abort();
}
mutex_unlock(&init_lock);
}
My question is below.
Why did not delete the chunk from registry_arena.chunk_list before munmap a chunk?
Thanks,
xin
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lttng-dev@lists.lttng.org
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^ permalink raw reply [flat|nested] 5+ messages in thread
* question about rcu_bp_exit()
@ 2016-05-18 9:44 songxin
0 siblings, 0 replies; 5+ messages in thread
From: songxin @ 2016-05-18 9:44 UTC (permalink / raw)
To: lttng-dev
[-- Attachment #1.1: Type: text/plain, Size: 1366 bytes --]
Hi,
Now I get a crash because receiving signal SIGSEGV as below.
#0 arena_alloc (arena=<optimized out>) at /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:432
#1 add_thread () at /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:462
#2 rcu_bp_register () at /usr/src/debug/liburcu/0.9.1+git5fd33b1e5003ca316bd314ec3fd1447f6199a282-r0/git/urcu-bp.c:541
I read the code of urcu-bp.c and found that "if (chunk->data_len - chunk->used < len)" is in 432 line. So I guess that the chunk is a illegal pointer.
Below is the function rcu_bp_exit().
static
void rcu_bp_exit(void)
{
mutex_lock(&init_lock);
if (!--rcu_bp_refcount) {
struct registry_chunk *chunk, *tmp;
int ret;
cds_list_for_each_entry_safe(chunk, tmp,
®istry_arena.chunk_list, node) {
munmap(chunk, chunk->data_len
+ sizeof(struct registry_chunk));
}
ret = pthread_key_delete(urcu_bp_key);
if (ret)
abort();
}
mutex_unlock(&init_lock);
}
My question is below.
Why did not delete the chunk from registry_arena.chunk_list before munmap a chunk?
Thanks,
xin
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^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-05-19 19:53 UTC | newest]
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2016-05-18 10:07 question about rcu_bp_exit() songxin
[not found] <6db07fb4.c6e5.154c340296f.Coremail.songxin_1980@126.com>
2016-05-18 18:40 ` Mathieu Desnoyers
[not found] ` <971830834.12745.1463596803434.JavaMail.zimbra@efficios.com>
2016-05-19 19:53 ` Paul E. McKenney
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