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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2023-06-07 13:19:02 +0300
committerThomas Gleixner <tglx@linutronix.de>2023-06-07 15:16:12 +0300
commit8b64d420fe2450f82848178506d3e3a0bd195539 (patch)
treec151d5a21d90099e0e54032094219ea83aeda72f /lib
parent7877cb91f1081754a1487c144d85dc0d2e2e7fc4 (diff)
downloadlinux-8b64d420fe2450f82848178506d3e3a0bd195539.tar.xz
debugobjects: Recheck debug_objects_enabled before reporting
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
Diffstat (limited to 'lib')
-rw-r--r--lib/debugobjects.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 984985c39c9b..a517256a270b 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -498,6 +498,15 @@ 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;