Date: Fri Sep 26 20:56:07 2014 +0000
fork.c: copy_process(): fix cleanup WRT perf_event_free_task()
Currently, in copy_process(), a failure of either sched_fork() or
perf_event_init_task() does trigger perf_event_free_task()!
Moreover, the label bad_fork_cleanup_policy does more than what its name
implies, because it includes perf_event_free_task()!
Let's explain the change with a grASCIIcally-enhanced kind-of-diff which
provides an adequate context.
// Read vertically this column
// | | | | | | | | |
// v v v v v v v v v
{
//SNIP//
if (clone_flags & CLONE_THREAD)
threadgroup_change_begin(current);
//SNIP//
#ifdef CONFIG_NUMA
p->mempolicy = mpol_dup(p->mempolicy);
if (IS_ERR(p->mempolicy)) {
//SNIP//
goto bad_fork_cleanup_threadgroup_lock;
}
#endif
//SNIP//
retval = sched_fork(clone_flags, p);
if (retval)
// // mustn't perf_event_free_task()
goto bad_fork_cleanup_policy;
retval = perf_event_init_task(p);
if (retval)
// // mustn't perf_event_free_task()
goto bad_fork_cleanup_policy;
retval = audit_alloc(p);
if (retval)
// // must perf_event_free_task()
// @@ Hence change this way:
- goto bad_fork_cleanup_policy;
+ goto bad_fork_cleanup_perf;
//SNIP//
bad_fork_cleanup_audit:
audit_free(p);
// // let's clean perf up
// @@ Hence change this way:
-bad_fork_cleanup_policy:
+bad_fork_cleanup_perf:
perf_event_free_task(p);
// // no (longer) need to clean perf up
// @@ Hence change this way:
+bad_fork_cleanup_policy:
#ifdef CONFIG_NUMA
mpol_put(p->mempolicy);
bad_fork_cleanup_threadgroup_lock:
#endif
if (clone_flags & CLONE_THREAD)
threadgroup_change_end(current);
//SNIP//
}
Signed-off-by: Sylvain "ythier" Hitier <[email protected]>
---
kernel/fork.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index 0cf9cdb..a91e47d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1360,7 +1360,7 @@ static struct task_struct *copy_process(unsigned long
clone_flags,
goto bad_fork_cleanup_policy;
retval = audit_alloc(p);
if (retval)
- goto bad_fork_cleanup_policy;
+ goto bad_fork_cleanup_perf;
/* copy all the process information */
shm_init_task(p);
retval = copy_semundo(clone_flags, p);
@@ -1566,8 +1566,9 @@ bad_fork_cleanup_semundo:
exit_sem(p);
bad_fork_cleanup_audit:
audit_free(p);
-bad_fork_cleanup_policy:
+bad_fork_cleanup_perf:
perf_event_free_task(p);
+bad_fork_cleanup_policy:
#ifdef CONFIG_NUMA
mpol_put(p->mempolicy);
bad_fork_cleanup_threadgroup_lock:
Regards,
Sylvain "ythier" Hitier
--
Business is about being busy, not being rich...
Lived 777 days in a Debian package => http://en.wikipedia.org/wiki/Apt,_Vaucluse
There's THE room for ideals in this mechanical place!
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