diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2025-10-09 12:43:38 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-10-14 03:33:32 +0300 |
| commit | 25718fdcbdd2dadd15fc8b684df59b43970b91ed (patch) | |
| tree | 03b00c8ffae18147239cf41deffc22c5e75020af | |
| parent | fcb8b32a68fd40b0440cb9468cf6f6ab9de9f3c5 (diff) | |
| download | linux-25718fdcbdd2dadd15fc8b684df59b43970b91ed.tar.xz | |
net: gro_cells: Use nested-BH locking for gro_cell
The gro_cell data structure is per-CPU variable and relies on disabled
BH for its locking. Without per-CPU locking in local_bh_disable() on
PREEMPT_RT this data structure requires explicit locking.
Add a local_lock_t to the data structure and use
local_lock_nested_bh() for locking. This change adds only lockdep
coverage and does not alter the functional behaviour for !PREEMPT_RT.
Reported-by: syzbot+8715dd783e9b0bef43b1@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68c6c3b1.050a0220.2ff435.0382.GAE@google.com/
Fixes: 3253cb49cbad ("softirq: Allow to drop the softirq-BKL lock on PREEMPT_RT")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20251009094338.j1jyKfjR@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/gro_cells.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/net/core/gro_cells.c b/net/core/gro_cells.c index ff8e5b64bf6b..b43911562f4d 100644 --- a/net/core/gro_cells.c +++ b/net/core/gro_cells.c @@ -8,11 +8,13 @@ struct gro_cell { struct sk_buff_head napi_skbs; struct napi_struct napi; + local_lock_t bh_lock; }; int gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb) { struct net_device *dev = skb->dev; + bool have_bh_lock = false; struct gro_cell *cell; int res; @@ -25,6 +27,8 @@ int gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb) goto unlock; } + local_lock_nested_bh(&gcells->cells->bh_lock); + have_bh_lock = true; cell = this_cpu_ptr(gcells->cells); if (skb_queue_len(&cell->napi_skbs) > READ_ONCE(net_hotdata.max_backlog)) { @@ -39,6 +43,9 @@ drop: if (skb_queue_len(&cell->napi_skbs) == 1) napi_schedule(&cell->napi); + if (have_bh_lock) + local_unlock_nested_bh(&gcells->cells->bh_lock); + res = NET_RX_SUCCESS; unlock: @@ -54,6 +61,7 @@ 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) { skb = __skb_dequeue(&cell->napi_skbs); if (!skb) @@ -64,6 +72,7 @@ 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; } @@ -79,6 +88,7 @@ int gro_cells_init(struct gro_cells *gcells, struct net_device *dev) struct gro_cell *cell = per_cpu_ptr(gcells->cells, i); __skb_queue_head_init(&cell->napi_skbs); + local_lock_init(&cell->bh_lock); set_bit(NAPI_STATE_NO_BUSY_POLL, &cell->napi.state); |