diff options
| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2023-06-07 19:19:02 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-07-27 08:44:36 +0200 |
| commit | 5f84a34b646f6e52fa8d39bd6f586264c0e68703 (patch) | |
| tree | a5a252246b79bcb876619ec10bb18e6619602f71 /lib | |
| parent | 5d5aa5b64887689d73ef7a4d5c17c2dfcfb26812 (diff) | |
debugobjects: Recheck debug_objects_enabled before reporting
[ Upstream commit 8b64d420fe2450f82848178506d3e3a0bd195539 ]
syzbot is reporting false a positive ODEBUG message immediately after
ODEBUG was disabled due to OOM.
[ 1062.309646][T22911] ODEBUG: Out of memory. ODEBUG disabled
[ 1062.886755][ T5171] ------------[ cut here ]------------
[ 1062.892770][ T5171] ODEBUG: assert_init not available (active state 0) object: ffffc900056afb20 object type: timer_list hint: process_timeout+0x0/0x40
CPU 0 [ T5171] CPU 1 [T22911]
-------------- --------------
debug_object_assert_init() {
if (!debug_objects_enabled)
return;
db = get_bucket(addr);
lookup_object_or_alloc() {
debug_objects_enabled = 0;
return NULL;
}
debug_objects_oom() {
pr_warn("Out of memory. ODEBUG disabled\n");
// all buckets get emptied here, and
}
lookup_object_or_alloc(addr, db, descr, false, true) {
// this bucket is already empty.
return ERR_PTR(-ENOENT);
}
// Emits false positive warning.
debug_print_object(&o, "assert_init");
}
Recheck debug_object_enabled in debug_print_object() to avoid that.
Reported-by: syzbot <syzbot+7937ba6a50bdd00fffdf@syzkaller.appspotmail.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/492fe2ae-5141-d548-ebd5-62f5fe2e57f7@I-love.SAKURA.ne.jp
Closes: https://syzkaller.appspot.com/bug?extid=7937ba6a50bdd00fffdf
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/debugobjects.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 4c39678c03ee..4dd9283f6fea 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -501,6 +501,15 @@ static void debug_print_object(struct debug_obj *obj, char *msg) const struct debug_obj_descr *descr = obj->descr; static int limit; + /* + * Don't report if lookup_object_or_alloc() by the current thread + * failed because lookup_object_or_alloc()/debug_objects_oom() by a + * concurrent thread turned off debug_objects_enabled and cleared + * the hash buckets. + */ + if (!debug_objects_enabled) + return; + if (limit < 5 && descr != descr_test) { void *hint = descr->debug_hint ? descr->debug_hint(obj->object) : NULL; |