2021-04-02 08:57:07

by 赵军奎

[permalink] [raw]
Subject: [PATCH] drm/nouveau: fix potential abnormal lock/unlock

Fix coccicheck warning:
drivers/gpu/drm/nouveau/nvkm/engine/fifo/base.c:115:3-9: preceding lock on line 109
drivers/gpu/drm/nouveau/nvkm/engine/fifo/base.c:98:2-8: preceding lock on line 95

As we see, function nvkm_fifo_chan_inst & nvkm_fifo_chan_chid both
use spin_lock_irqsave, but no spin_unlock_irqrestore in if/return
branch, seems like a potential bug?

Signed-off-by: Bernard Zhao <[email protected]>
---
drivers/gpu/drm/nouveau/nvkm/engine/fifo/base.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/fifo/base.c b/drivers/gpu/drm/nouveau/nvkm/engine/fifo/base.c
index 2ed4ff05d207..e3f624d97644 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/fifo/base.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/fifo/base.c
@@ -95,6 +95,7 @@ nvkm_fifo_chan_inst(struct nvkm_fifo *fifo, u64 inst, unsigned long *rflags)
spin_lock_irqsave(&fifo->lock, flags);
if ((chan = nvkm_fifo_chan_inst_locked(fifo, inst))) {
*rflags = flags;
+ spin_unlock_irqrestore(&fifo->lock, flags);
return chan;
}
spin_unlock_irqrestore(&fifo->lock, flags);
@@ -112,6 +113,7 @@ nvkm_fifo_chan_chid(struct nvkm_fifo *fifo, int chid, unsigned long *rflags)
list_del(&chan->head);
list_add(&chan->head, &fifo->chan);
*rflags = flags;
+ spin_unlock_irqrestore(&fifo->lock, flags);
return chan;
}
}
--
2.31.0