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| author |   Jason Xing <kerneljasonxing@gmail.com> | 2025-02-14 14:42:50 +0800 |
|---|---|---|
| committer |   Paolo Abeni <pabeni@redhat.com> | 2025-02-18 12:48:29 +0100 |
| commit | 43130d02baa137033c25297aaae95fd0edc41654 (patch) | |
| tree | b762ec0f04bcff933953015b581b206e83c926c5 /net | |
| parent | Merge branch 'add-af_xdp-support-for-cn10k' (diff) | |
| download | wireguard-linux-43130d02baa137033c25297aaae95fd0edc41654.tar.xz wireguard-linux-43130d02baa137033c25297aaae95fd0edc41654.zip | |
page_pool: avoid infinite loop to schedule delayed worker
We noticed the kworker in page_pool_release_retry() was waken
up repeatedly and infinitely in production because of the
buggy driver causing the inflight less than 0 and warning
us in page_pool_inflight()[1].
Since the inflight value goes negative, it means we should
not expect the whole page_pool to get back to work normally.
This patch mitigates the adverse effect by not rescheduling
the kworker when detecting the inflight negative in
page_pool_release_retry().
[1]
[Mon Feb 10 20:36:11 2025] ------------[ cut here ]------------
[Mon Feb 10 20:36:11 2025] Negative(-51446) inflight packet-pages
...
[Mon Feb 10 20:36:11 2025] Call Trace:
[Mon Feb 10 20:36:11 2025] page_pool_release_retry+0x23/0x70
[Mon Feb 10 20:36:11 2025] process_one_work+0x1b1/0x370
[Mon Feb 10 20:36:11 2025] worker_thread+0x37/0x3a0
[Mon Feb 10 20:36:11 2025] kthread+0x11a/0x140
[Mon Feb 10 20:36:11 2025] ? process_one_work+0x370/0x370
[Mon Feb 10 20:36:11 2025] ? __kthread_cancel_work+0x40/0x40
[Mon Feb 10 20:36:11 2025] ret_from_fork+0x35/0x40
[Mon Feb 10 20:36:11 2025] ---[ end trace ebffe800f33e7e34 ]---
Note: before this patch, the above calltrace would flood the
dmesg due to repeated reschedule of release_dw kworker.
Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Link: https://patch.msgid.link/20250214064250.85987-1-kerneljasonxing@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/page_pool.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 1c6fec08bc43..acef1fcd8ddc 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -1112,7 +1112,13 @@ static void page_pool_release_retry(struct work_struct *wq) int inflight; inflight = page_pool_release(pool); - if (!inflight) + /* In rare cases, a driver bug may cause inflight to go negative. + * Don't reschedule release if inflight is 0 or negative. + * - If 0, the page_pool has been destroyed + * - if negative, we will never recover + * in both cases no reschedule is necessary. + */ + if (inflight <= 0) return; /* Periodic warning for page pools the user can't see */ |