> -----Original Message-----
> From: Eric Dumazet <eric.duma...@gmail.com>
> Sent: Monday, February 22, 2021 11:42 AM
> To: Danielle Ratson <daniel...@nvidia.com>; netdev@vger.kernel.org
> Cc: da...@davemloft.net; k...@kernel.org; Jiri Pirko <j...@nvidia.com>;
> and...@lunn.ch; f.faine...@gmail.com;
> mkube...@suse.cz; mlxsw <ml...@nvidia.com>; Ido Schimmel <ido...@nvidia.com>
> Subject: Re: [PATCH net-next v4 3/8] ethtool: Get link mode in use instead of
> speed and duplex parameters
>
>
>
> On 2/2/21 7:06 PM, Danielle Ratson wrote:
> > Currently, when user space queries the link's parameters, as speed and
> > duplex, each parameter is passed from the driver to ethtool.
> >
> > Instead, get the link mode bit in use, and derive each of the
> > parameters from it in ethtool.
> >
> > Signed-off-by: Danielle Ratson <daniel...@nvidia.com>
> > ---
> >
> > Notes:
> > v3:
> > * Remove 'ETHTOOL_A_LINKMODES_LINK_MODE' from Documentation
> > since
> > it is not used.
> > * Remove LINK_MODE_UNKNOWN from uapi.
> > * Remove an unnecessary loop.
> > * Move link_mode_info and link_mode_params to common file.
> > * Move the speed, duplex and lanes derivation to the wrapper
> > __ethtool_get_link_ksettings().
> >
> > include/linux/ethtool.h | 1 +
> > net/ethtool/common.c | 147 +++++++++++++++++++++++++++++++++++++
> > net/ethtool/common.h | 7 ++
> > net/ethtool/ioctl.c | 18 ++++-
> > net/ethtool/linkmodes.c | 157
> > +---------------------------------------
> > 5 files changed, 174 insertions(+), 156 deletions(-)
> >
> > diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h index
> > 1ab13c5dfb2f..ec4cd3921c67 100644
> > --- a/include/linux/ethtool.h
> > +++ b/include/linux/ethtool.h
> > @@ -129,6 +129,7 @@ struct ethtool_link_ksettings {
> > __ETHTOOL_DECLARE_LINK_MODE_MASK(lp_advertising);
> > } link_modes;
> > u32 lanes;
> > + enum ethtool_link_mode_bit_indices link_mode;
>
> Some drivers blindly use ethtool_link_ksettings without knowing a new field
> has been added.
>
> (See below)
>
> > };
> >
> > /**
> > diff --git a/net/ethtool/common.c b/net/ethtool/common.c index
> > 181220101a6e..835b9bba3e7e 100644
> > --- a/net/ethtool/common.c
> > +++ b/net/ethtool/common.c
> > @@ -198,6 +198,153 @@ const char link_mode_names[][ETH_GSTRING_LEN] =
> > { };
> > static_assert(ARRAY_SIZE(link_mode_names) ==
> > __ETHTOOL_LINK_MODE_MASK_NBITS);
> >
> > +#define __LINK_MODE_LANES_CR 1
> > +#define __LINK_MODE_LANES_CR2 2
> > +#define __LINK_MODE_LANES_CR4 4
> > +#define __LINK_MODE_LANES_CR8 8
> > +#define __LINK_MODE_LANES_DR 1
> > +#define __LINK_MODE_LANES_DR2 2
> > +#define __LINK_MODE_LANES_DR4 4
> > +#define __LINK_MODE_LANES_DR8 8
> > +#define __LINK_MODE_LANES_KR 1
> > +#define __LINK_MODE_LANES_KR2 2
> > +#define __LINK_MODE_LANES_KR4 4
> > +#define __LINK_MODE_LANES_KR8 8
> > +#define __LINK_MODE_LANES_SR 1
> > +#define __LINK_MODE_LANES_SR2 2
> > +#define __LINK_MODE_LANES_SR4 4
> > +#define __LINK_MODE_LANES_SR8 8
> > +#define __LINK_MODE_LANES_ER 1
> > +#define __LINK_MODE_LANES_KX 1
> > +#define __LINK_MODE_LANES_KX4 4
> > +#define __LINK_MODE_LANES_LR 1
> > +#define __LINK_MODE_LANES_LR4 4
> > +#define __LINK_MODE_LANES_LR4_ER4 4
> > +#define __LINK_MODE_LANES_LR_ER_FR 1
> > +#define __LINK_MODE_LANES_LR2_ER2_FR2 2
> > +#define __LINK_MODE_LANES_LR4_ER4_FR4 4
> > +#define __LINK_MODE_LANES_LR8_ER8_FR8 8
> > +#define __LINK_MODE_LANES_LRM 1
> > +#define __LINK_MODE_LANES_MLD2 2
> > +#define __LINK_MODE_LANES_T 1
> > +#define __LINK_MODE_LANES_T1 1
> > +#define __LINK_MODE_LANES_X 1
> > +#define __LINK_MODE_LANES_FX 1
> > +
> > +#define __DEFINE_LINK_MODE_PARAMS(_speed, _type, _duplex) \
> > + [ETHTOOL_LINK_MODE(_speed, _type, _duplex)] = { \
> > + .speed = SPEED_ ## _speed, \
> > + .lanes = __LINK_MODE_LANES_ ## _type, \
> > + .duplex = __DUPLEX_ ## _duplex \
> > + }
> > +#define __DUPLEX_Half DUPLEX_HALF
> > +#define __DUPLEX_Full DUPLEX_FULL
> > +#define __DEFINE_SPECIAL_MODE_PARAMS(_mode) \
> > + [ETHTOOL_LINK_MODE_ ## _mode ## _BIT] = { \
> > + .speed = SPEED_UNKNOWN, \
> > + .lanes = 0, \
> > + .duplex = DUPLEX_UNKNOWN, \
> > + }
> > +
> > +const struct link_mode_info link_mode_params[] = {
> > + __DEFINE_LINK_MODE_PARAMS(10, T, Half),
> > + __DEFINE_LINK_MODE_PARAMS(10, T, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100, T, Half),
> > + __DEFINE_LINK_MODE_PARAMS(100, T, Full),
> > + __DEFINE_LINK_MODE_PARAMS(1000, T, Half),
> > + __DEFINE_LINK_MODE_PARAMS(1000, T, Full),
> > + __DEFINE_SPECIAL_MODE_PARAMS(Autoneg),
> > + __DEFINE_SPECIAL_MODE_PARAMS(TP),
> > + __DEFINE_SPECIAL_MODE_PARAMS(AUI),
> > + __DEFINE_SPECIAL_MODE_PARAMS(MII),
> > + __DEFINE_SPECIAL_MODE_PARAMS(FIBRE),
> > + __DEFINE_SPECIAL_MODE_PARAMS(BNC),
> > + __DEFINE_LINK_MODE_PARAMS(10000, T, Full),
> > + __DEFINE_SPECIAL_MODE_PARAMS(Pause),
> > + __DEFINE_SPECIAL_MODE_PARAMS(Asym_Pause),
> > + __DEFINE_LINK_MODE_PARAMS(2500, X, Full),
> > + __DEFINE_SPECIAL_MODE_PARAMS(Backplane),
> > + __DEFINE_LINK_MODE_PARAMS(1000, KX, Full),
> > + __DEFINE_LINK_MODE_PARAMS(10000, KX4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(10000, KR, Full),
> > + [ETHTOOL_LINK_MODE_10000baseR_FEC_BIT] = {
> > + .speed = SPEED_10000,
> > + .duplex = DUPLEX_FULL,
> > + },
> > + __DEFINE_LINK_MODE_PARAMS(20000, MLD2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(20000, KR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(40000, KR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(40000, CR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(40000, SR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(40000, LR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(56000, KR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(56000, CR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(56000, SR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(56000, LR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(25000, CR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(25000, KR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(25000, SR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(50000, CR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(50000, KR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, KR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, SR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, CR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, LR4_ER4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(50000, SR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(1000, X, Full),
> > + __DEFINE_LINK_MODE_PARAMS(10000, CR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(10000, SR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(10000, LR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(10000, LRM, Full),
> > + __DEFINE_LINK_MODE_PARAMS(10000, ER, Full),
> > + __DEFINE_LINK_MODE_PARAMS(2500, T, Full),
> > + __DEFINE_LINK_MODE_PARAMS(5000, T, Full),
> > + __DEFINE_SPECIAL_MODE_PARAMS(FEC_NONE),
> > + __DEFINE_SPECIAL_MODE_PARAMS(FEC_RS),
> > + __DEFINE_SPECIAL_MODE_PARAMS(FEC_BASER),
> > + __DEFINE_LINK_MODE_PARAMS(50000, KR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(50000, SR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(50000, CR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(50000, LR_ER_FR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(50000, DR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, KR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, SR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, CR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, LR2_ER2_FR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, DR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(200000, KR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(200000, SR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(200000, LR4_ER4_FR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(200000, DR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(200000, CR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100, T1, Full),
> > + __DEFINE_LINK_MODE_PARAMS(1000, T1, Full),
> > + __DEFINE_LINK_MODE_PARAMS(400000, KR8, Full),
> > + __DEFINE_LINK_MODE_PARAMS(400000, SR8, Full),
> > + __DEFINE_LINK_MODE_PARAMS(400000, LR8_ER8_FR8, Full),
> > + __DEFINE_LINK_MODE_PARAMS(400000, DR8, Full),
> > + __DEFINE_LINK_MODE_PARAMS(400000, CR8, Full),
> > + __DEFINE_SPECIAL_MODE_PARAMS(FEC_LLRS),
> > + __DEFINE_LINK_MODE_PARAMS(100000, KR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, SR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, LR_ER_FR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, DR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100000, CR, Full),
> > + __DEFINE_LINK_MODE_PARAMS(200000, KR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(200000, SR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(200000, LR2_ER2_FR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(200000, DR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(200000, CR2, Full),
> > + __DEFINE_LINK_MODE_PARAMS(400000, KR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(400000, SR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(400000, LR4_ER4_FR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(400000, DR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(400000, CR4, Full),
> > + __DEFINE_LINK_MODE_PARAMS(100, FX, Half),
> > + __DEFINE_LINK_MODE_PARAMS(100, FX, Full), };
> > +static_assert(ARRAY_SIZE(link_mode_params) ==
> > +__ETHTOOL_LINK_MODE_MASK_NBITS);
> > +
> > const char netif_msg_class_names[][ETH_GSTRING_LEN] = {
> > [NETIF_MSG_DRV_BIT] = "drv",
> > [NETIF_MSG_PROBE_BIT] = "probe",
> > diff --git a/net/ethtool/common.h b/net/ethtool/common.h index
> > 3d9251c95a8b..a9d071248698 100644
> > --- a/net/ethtool/common.h
> > +++ b/net/ethtool/common.h
> > @@ -14,6 +14,12 @@
> >
> > #define __SOF_TIMESTAMPING_CNT (const_ilog2(SOF_TIMESTAMPING_LAST) +
> > 1)
> >
> > +struct link_mode_info {
> > + int speed;
> > + u8 lanes;
> > + u8 duplex;
> > +};
> > +
> > extern const char
> > netdev_features_strings[NETDEV_FEATURE_COUNT][ETH_GSTRING_LEN];
> > extern const char
> > @@ -23,6 +29,7 @@
> > tunable_strings[__ETHTOOL_TUNABLE_COUNT][ETH_GSTRING_LEN];
> > extern const char
> > phy_tunable_strings[__ETHTOOL_PHY_TUNABLE_COUNT][ETH_GSTRING_LEN];
> > extern const char link_mode_names[][ETH_GSTRING_LEN];
> > +extern const struct link_mode_info link_mode_params[];
> > extern const char netif_msg_class_names[][ETH_GSTRING_LEN];
> > extern const char wol_mode_names[][ETH_GSTRING_LEN];
> > extern const char sof_timestamping_names[][ETH_GSTRING_LEN];
> > diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c index
> > 771688e1b0da..24783b71c584 100644
> > --- a/net/ethtool/ioctl.c
> > +++ b/net/ethtool/ioctl.c
> > @@ -426,13 +426,29 @@ struct ethtool_link_usettings { int
> > __ethtool_get_link_ksettings(struct net_device *dev,
> > struct ethtool_link_ksettings *link_ksettings)
> > {
> > + const struct link_mode_info *link_info;
> > + int err;
> > +
> > ASSERT_RTNL();
> >
> > if (!dev->ethtool_ops->get_link_ksettings)
> > return -EOPNOTSUPP;
> >
> > memset(link_ksettings, 0, sizeof(*link_ksettings));
> > - return dev->ethtool_ops->get_link_ksettings(dev, link_ksettings);
> > +
> > + link_ksettings->link_mode = -1;
> > + err = dev->ethtool_ops->get_link_ksettings(dev, link_ksettings);
> > + if (err)
> > + return err;
>
> If a driver like drivers/net/tun.c does a complete
>
> memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
>
> then the link_ksettings->link_mode is overwritten with possible garbage data.
>
> > +
> > + if (link_ksettings->link_mode != -1) {
> > + link_info = &link_mode_params[link_ksettings->link_mode];
> > + link_ksettings->base.speed = link_info->speed;
> > + link_ksettings->lanes = link_info->lanes;
> > + link_ksettings->base.duplex = link_info->duplex;
> > + }
> > +
> > + return 0;
>
>
> general protection fault, probably for non-canonical address
> 0xdffffc00f14cc32c: 0000 [#1] PREEMPT SMP KASAN
> KASAN: probably user-memory-access in range
> [0x000000078a661960-0x000000078a661967]
> CPU: 0 PID: 8452 Comm: syz-executor360 Not tainted 5.11.0-syzkaller #0
> Hardware name: Google Google Compute Engine/Google
> Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:__ethtool_get_link_ksettings+0x1a3/0x3a0 net/ethtool/ioctl.c:446
> Code: b7 3e fa 83 fd ff 0f 84 30 01 00 00 e8 16 b0 3e fa 48 8d 3c ed 60 d5 69
> 8a 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14
> 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 b9
> RSP: 0018:ffffc900019df7a0 EFLAGS: 00010202
> RAX: dffffc0000000000 RBX: ffff888026136008 RCX: 0000000000000000
> RDX: 00000000f14cc32c RSI: ffffffff873439ca RDI: 000000078a661960
> RBP: 00000000ffff8880 R08: 00000000ffffffff R09: ffff88802613606f
> R10: ffffffff873439bc R11: 0000000000000000 R12: 0000000000000000
> R13: ffff88802613606c R14: ffff888011d0c210 R15: ffff888011d0c210
> FS: 0000000000749300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000004b60f0 CR3: 00000000185c2000 CR4: 00000000001506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace:
> linkinfo_prepare_data+0xfd/0x280 net/ethtool/linkinfo.c:37
> ethnl_default_notify+0x1dc/0x630 net/ethtool/netlink.c:586
> ethtool_notify+0xbd/0x1f0 net/ethtool/netlink.c:656
> ethtool_set_link_ksettings+0x277/0x330 net/ethtool/ioctl.c:620
> dev_ethtool+0x2b35/0x45d0 net/ethtool/ioctl.c:2842
> dev_ioctl+0x463/0xb70 net/core/dev_ioctl.c:440
> sock_do_ioctl+0x148/0x2d0 net/socket.c:1060
> sock_ioctl+0x477/0x6a0 net/socket.c:1177 vfs_ioctl fs/ioctl.c:48 [inline]
> __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl
> fs/ioctl.c:739 [inline]
> __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
> do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x440c79
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 90 48 89 f8 48 89 f7 48
> 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01
> f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffe7a6e6fc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000440c79
> RDX: 0000000020000380 RSI: 0000000000008946 RDI: 0000000000000004
> RBP: 0000000000000000 R08: 0000000000f0b5ff R09: 0000000000f0b5ff
> R10: 0000000000f0b5ff R11: 0000000000000246 R12: 00000000000109be
> R13: 00007ffe7a6e6ff0 R14: 00007ffe7a6e6fe0 R15: 00007ffe7a6e6fd4 Modules
> linked in:
> ---[ end trace 881142e6c455c35b ]---
> RIP: 0010:__ethtool_get_link_ksettings+0x1a3/0x3a0 net/ethtool/ioctl.c:446
> Code: b7 3e fa 83 fd ff 0f 84 30 01 00 00 e8 16 b0 3e fa 48 8d 3c ed 60 d5 69
> 8a 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14
> 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 b9
> RSP: 0018:ffffc900019df7a0 EFLAGS: 00010202
> RAX: dffffc0000000000 RBX: ffff888026136008 RCX: 0000000000000000
> RDX: 00000000f14cc32c RSI: ffffffff873439ca RDI: 000000078a661960
> RBP: 00000000ffff8880 R08: 00000000ffffffff R09: ffff88802613606f
> R10: ffffffff873439bc R11: 0000000000000000 R12: 0000000000000000
> R13: ffff88802613606c R14: ffff888011d0c210 R15: ffff888011d0c210
> FS: 0000000000749300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f4f9803d058 CR3: 00000000185c2000 CR4: 00000000001506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>
Thank you for you catch Eric.
Ill go over all the get_link_ksettings functions and adjust them so link_mode
will be equal to -1 instead of garbage value, in cases like you mentioned.
