* [RFA] Fix leaks when pruning inferiors.
@ 2019-12-01 15:52 Philippe Waroquiers
2019-12-05 16:42 ` Pedro Alves
2019-12-05 16:44 ` Kevin Buettner
0 siblings, 2 replies; 4+ messages in thread
From: Philippe Waroquiers @ 2019-12-01 15:52 UTC (permalink / raw)
To: gdb-patches; +Cc: Philippe Waroquiers
Valgrind detects various inferior related leaks, such as:
==31877== 5,530 (56 direct, 5,474 indirect) bytes in 1 blocks are definitely lost in loss record 7,131 of 7,355
==31877== at 0x4C2E18C: calloc (vg_replace_malloc.c:760)
==31877== by 0x23E580: xcalloc (alloc.c:100)
==31877== by 0x4794A9: xcnewvec<void*> (poison.h:158)
==31877== by 0x4794A9: registry_alloc_data(registry_data_registry*, registry_fields*) (registry.c:51)
==31877== by 0x3A537C: inferior_alloc_data (inferior.c:43)
==31877== by 0x3A537C: inferior::inferior(int) (inferior.c:92)
==31877== by 0x3A5426: add_inferior_silent(int) (inferior.c:98)
==31877== by 0x3A5530: add_inferior(int) (inferior.c:122)
...
Origin of the leaks is in prune_inferiors: prune_inferiors is first removing
the inferior to prune from the inferior list, then calls delete_inferior.
But delete_inferior will only really destroy the inferior when it finds
it into the inferior list.
As delete_inferior is removing the inferior to delete from the inferior list,
ensure prune_inferiors only calls delete_inferior, without touching the
inferior list.
gdb/ChangeLog
YYYY-MM-DD Philippe Waroquiers <philippe.waroquiers@skynet.be>
* inferior.c (prune_inferiors): Only call delete_inferior,
Do not modify the inferior list.
---
gdb/inferior.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/gdb/inferior.c b/gdb/inferior.c
index 84e4d24e73..55c8409cd9 100644
--- a/gdb/inferior.c
+++ b/gdb/inferior.c
@@ -370,24 +370,22 @@ have_live_inferiors (void)
void
prune_inferiors (void)
{
- struct inferior *ss, **ss_link;
+ struct inferior *ss, *ss_next;
ss = inferior_list;
- ss_link = &inferior_list;
while (ss)
{
if (!ss->deletable ()
|| !ss->removable
|| ss->pid != 0)
{
- ss_link = &ss->next;
- ss = *ss_link;
+ ss = ss->next;
continue;
}
- *ss_link = ss->next;
+ ss_next = ss->next;
delete_inferior (ss);
- ss = *ss_link;
+ ss = ss_next;
}
}
--
2.20.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RFA] Fix leaks when pruning inferiors.
2019-12-01 15:52 [RFA] Fix leaks when pruning inferiors Philippe Waroquiers
@ 2019-12-05 16:42 ` Pedro Alves
2019-12-05 22:30 ` Philippe Waroquiers
2019-12-05 16:44 ` Kevin Buettner
1 sibling, 1 reply; 4+ messages in thread
From: Pedro Alves @ 2019-12-05 16:42 UTC (permalink / raw)
To: Philippe Waroquiers, gdb-patches
On 12/1/19 3:52 PM, Philippe Waroquiers wrote:
> Origin of the leaks is in prune_inferiors: prune_inferiors is first removing
> the inferior to prune from the inferior list, then calls delete_inferior.
> But delete_inferior will only really destroy the inferior when it finds
> it into the inferior list.
> As delete_inferior is removing the inferior to delete from the inferior list,
> ensure prune_inferiors only calls delete_inferior, without touching the
> inferior list.
Whoops.
> @@ -370,24 +370,22 @@ have_live_inferiors (void)
> void
> prune_inferiors (void)
> {
> - struct inferior *ss, **ss_link;
> + struct inferior *ss, *ss_next;
>
>
> - *ss_link = ss->next;
> + ss_next = ss->next;
> delete_inferior (ss);
> - ss = *ss_link;
> + ss = ss_next;
Please declare ss_next here instead of at the top.
You can omit the redundant "struct" while at it:
inferior *next = ss->next;
delete_inferior (ss);
ss = next;
OK with that change. Thanks!
Pedro Alves
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RFA] Fix leaks when pruning inferiors.
2019-12-01 15:52 [RFA] Fix leaks when pruning inferiors Philippe Waroquiers
2019-12-05 16:42 ` Pedro Alves
@ 2019-12-05 16:44 ` Kevin Buettner
1 sibling, 0 replies; 4+ messages in thread
From: Kevin Buettner @ 2019-12-05 16:44 UTC (permalink / raw)
To: gdb-patches; +Cc: Philippe Waroquiers
On Sun, 1 Dec 2019 16:52:20 +0100
Philippe Waroquiers <philippe.waroquiers@skynet.be> wrote:
> Valgrind detects various inferior related leaks, such as:
> ==31877== 5,530 (56 direct, 5,474 indirect) bytes in 1 blocks are definitely lost in loss record 7,131 of 7,355
> ==31877== at 0x4C2E18C: calloc (vg_replace_malloc.c:760)
> ==31877== by 0x23E580: xcalloc (alloc.c:100)
> ==31877== by 0x4794A9: xcnewvec<void*> (poison.h:158)
> ==31877== by 0x4794A9: registry_alloc_data(registry_data_registry*, registry_fields*) (registry.c:51)
> ==31877== by 0x3A537C: inferior_alloc_data (inferior.c:43)
> ==31877== by 0x3A537C: inferior::inferior(int) (inferior.c:92)
> ==31877== by 0x3A5426: add_inferior_silent(int) (inferior.c:98)
> ==31877== by 0x3A5530: add_inferior(int) (inferior.c:122)
> ...
>
> Origin of the leaks is in prune_inferiors: prune_inferiors is first removing
> the inferior to prune from the inferior list, then calls delete_inferior.
> But delete_inferior will only really destroy the inferior when it finds
> it into the inferior list.
> As delete_inferior is removing the inferior to delete from the inferior list,
> ensure prune_inferiors only calls delete_inferior, without touching the
> inferior list.
>
> gdb/ChangeLog
> YYYY-MM-DD Philippe Waroquiers <philippe.waroquiers@skynet.be>
> * inferior.c (prune_inferiors): Only call delete_inferior,
> Do not modify the inferior list.
Okay.
(Though I'd rather see a semicolon or a period in place of the comma in
the ChangeLog entry.)
Kevin
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RFA] Fix leaks when pruning inferiors.
2019-12-05 16:42 ` Pedro Alves
@ 2019-12-05 22:30 ` Philippe Waroquiers
0 siblings, 0 replies; 4+ messages in thread
From: Philippe Waroquiers @ 2019-12-05 22:30 UTC (permalink / raw)
To: Pedro Alves, gdb-patches
On Thu, 2019-12-05 at 16:42 +0000, Pedro Alves wrote:
> Please declare ss_next here instead of at the top.
> You can omit the redundant "struct" while at it:
>
> inferior *next = ss->next;
> delete_inferior (ss);
> ss = next;
>
> OK with that change. Thanks!
Pushed after fixing the above,
and the ChangeLog message as suggested by Kevin.
Thanks for the review.
Philippe
^ permalink raw reply [flat|nested] 4+ messages in thread
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2019-12-01 15:52 [RFA] Fix leaks when pruning inferiors Philippe Waroquiers
2019-12-05 16:42 ` Pedro Alves
2019-12-05 22:30 ` Philippe Waroquiers
2019-12-05 16:44 ` Kevin Buettner
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