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Message-ID: <5fa8dfeb-8eb6-0de0-a335-e0b4336c29e0@I-love.SAKURA.ne.jp>
Date: Sat, 27 May 2023 20:04:11 +0900
From: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
To: Eric Dumazet <edumazet@...gle.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
"David S. Miller" <davem@...emloft.net>
Cc: LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] ref_tracker: add stack_depot_save() failure handling to
ref_tracker_alloc()
stack_depot_save() cannot accept __GFP_NOFAIL flag because
__stack_depot_save() drops gfp flags which are not in
GFP_KERNEL | GFP_ATOMIC | __GFP_NOWARN. Also, changing
__stack_depot_save() to accept __GFP_NOFAIL is not possible
because rmqueue() does not want __GFP_NOFAIL flag for
order == DEPOT_POOL_ORDER allocation request.
Therefore, assume that stack_depot_save(GFP_KERNEL | __GFP_NOFAIL) from
ref_tracker_alloc() can silently fail, and emit "unreliable refcount
tracker." message.
Signed-off-by: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
---
lib/ref_tracker.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index dc7b14aa3431..ad48ff19adb2 100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -84,12 +84,18 @@ int ref_tracker_alloc(struct ref_tracker_dir *dir,
gfp_mask |= __GFP_NOFAIL;
*trackerp = tracker = kzalloc(sizeof(*tracker), gfp_mask);
if (unlikely(!tracker)) {
+nomem:
pr_err_once("memory allocation failure, unreliable refcount tracker.\n");
refcount_inc(&dir->untracked);
return -ENOMEM;
}
nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
tracker->alloc_stack_handle = stack_depot_save(entries, nr_entries, gfp);
+ if (!tracker->alloc_stack_handle) {
+ *trackerp = NULL;
+ kfree(tracker);
+ goto nomem;
+ }
spin_lock_irqsave(&dir->lock, flags);
list_add(&tracker->head, &dir->list);
--
2.18.4
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