Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH] [net-next] net: stmmac: fix gcc-10 -Wrestrict warning | Date | Wed, 21 Apr 2021 14:38:27 +0000 |
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From: Arnd Bergmann > Sent: 21 April 2021 14:47 > > From: Arnd Bergmann <arnd@arndb.de> > > gcc-10 and later warn about a theoretical array overrun when > accessing priv->int_name_rx_irq[i] with an out of bounds value > of 'i': > > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c: In function 'stmmac_request_irq_multi_msi': > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:3528:17: error: 'snprintf' argument 4 may overlap > destination object 'dev' [-Werror=restrict] > 3528 | snprintf(int_name, int_name_len, "%s:%s-%d", dev->name, "tx", i); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:3404:60: note: destination object referenced by > 'restrict'-qualified argument 1 was declared here > 3404 | static int stmmac_request_irq_multi_msi(struct net_device *dev) > | ~~~~~~~~~~~~~~~~~~~^~~ > > The warning is a bit strange since it's not actually about the array > bounds but rather about possible string operations with overlapping > arguments, but it's not technically wrong. > > Avoid the warning by adding an extra bounds check. > > Fixes: 8532f613bc78 ("net: stmmac: introduce MSI Interrupt routines for mac, safety, RX & TX") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > index d1ca07c846e6..aadac783687b 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > @@ -3498,6 +3498,8 @@ static int stmmac_request_irq_multi_msi(struct net_device *dev) > > /* Request Rx MSI irq */ > for (i = 0; i < priv->plat->rx_queues_to_use; i++) { > + if (i > MTL_MAX_RX_QUEUES) > + break; > if (priv->rx_irq[i] == 0) > continue;
It might be best to do: num_queues = min(priv->plat->rx_queues_to_use, MTL_MAX_RX_QUEUES); if (i = 0; i < num_queues; i++) { ...
Or just give up - if rx_queues_to_use is too big it's all gone horribly wrong already.
The compile must be smoking weed again.
David
- Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
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