diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2025-11-04 16:34:35 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-11-05 17:41:29 -0800 |
| commit | d917c217b612971ea05ae1582e8740b747e0e7e8 (patch) | |
| tree | 1826d13dd0fff057c7479cc85ba94add800db080 | |
| parent | b1d16f7c0063b7209fd3251ce40c77d37b477b83 (diff) | |
net: gro_cells: Reduce lock scope in gro_cell_poll
One GRO-cell device's NAPI callback can nest into the GRO-cell of
another device if the underlying device is also using GRO-cell.
This is the case for IPsec over vxlan.
These two GRO-cells are separate devices. From lockdep's point of view
it is the same because each device is sharing the same lock class and so
it reports a possible deadlock assuming one device is nesting into
itself.
Hold the bh_lock only while accessing gro_cell::napi_skbs in
gro_cell_poll(). This reduces the locking scope and avoids acquiring the
same lock class multiple times.
Fixes: 25718fdcbdd2 ("net: gro_cells: Use nested-BH locking for gro_cell")
Reported-by: Gal Pressman <gal@nvidia.com>
Closes: https://lore.kernel.org/all/66664116-edb8-48dc-ad72-d5223696dd19@nvidia.com/
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20251104153435.ty88xDQt@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/gro_cells.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/gro_cells.c b/net/core/gro_cells.c index fd57b845de33..a725d21159a6 100644 --- a/net/core/gro_cells.c +++ b/net/core/gro_cells.c @@ -60,9 +60,10 @@ static int gro_cell_poll(struct napi_struct *napi, int budget) struct sk_buff *skb; int work_done = 0; - __local_lock_nested_bh(&cell->bh_lock); while (work_done < budget) { + __local_lock_nested_bh(&cell->bh_lock); skb = __skb_dequeue(&cell->napi_skbs); + __local_unlock_nested_bh(&cell->bh_lock); if (!skb) break; napi_gro_receive(napi, skb); @@ -71,7 +72,6 @@ static int gro_cell_poll(struct napi_struct *napi, int budget) if (work_done < budget) napi_complete_done(napi, work_done); - __local_unlock_nested_bh(&cell->bh_lock); return work_done; } |