| Message ID | 20220408135629.590422-1-cascardo@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | [SRU,Bionic] ip6_gre: proper dev_{hold|put} in ndo_[un]init methods | expand |
Acked-by: Tim Gardner <tim.gardner@canonical.com> On 4/8/22 07:56, Thadeu Lima de Souza Cascardo wrote: > From: Eric Dumazet <edumazet@google.com> > > BugLink: https://bugs.launchpad.net/bugs/1968340 > > After adopting CONFIG_PCPU_DEV_REFCNT=n option, syzbot was able to trigger > a warning [1] > > Issue here is that: > > - all dev_put() should be paired with a corresponding dev_hold(), > and vice versa. > > - A driver doing a dev_put() in its ndo_uninit() MUST also > do a dev_hold() in its ndo_init(), only when ndo_init() > is returning 0. > > Otherwise, register_netdevice() would call ndo_uninit() > in its error path and release a refcount too soon. > > ip6_gre for example (among others problematic drivers) > has to use dev_hold() in ip6gre_tunnel_init_common() > instead of from ip6gre_newlink_common(), covering > both ip6gre_tunnel_init() and ip6gre_tap_init()/ > > Note that ip6gre_tunnel_init_common() is not called from > ip6erspan_tap_init() thus we also need to add a dev_hold() there, > as ip6erspan_tunnel_uninit() does call dev_put() > > [1] > refcount_t: decrement hit 0; leaking memory. > WARNING: CPU: 0 PID: 8422 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31 > Modules linked in: > CPU: 1 PID: 8422 Comm: syz-executor854 Not tainted 5.12.0-rc4-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31 > Code: 1d 6a 5a e8 09 31 ff 89 de e8 8d 1a ab fd 84 db 75 e0 e8 d4 13 ab fd 48 c7 c7 a0 e1 c1 89 c6 05 4a 5a e8 09 01 e8 2e 36 fb 04 <0f> 0b eb c4 e8 b8 13 ab fd 0f b6 1d 39 5a e8 09 31 ff 89 de e8 58 > RSP: 0018:ffffc900018befd0 EFLAGS: 00010282 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 > RDX: ffff88801ef19c40 RSI: ffffffff815c51f5 RDI: fffff52000317dec > RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 > R10: ffffffff815bdf8e R11: 0000000000000000 R12: ffff888018cf4568 > R13: ffff888018cf4c00 R14: ffff8880228f2000 R15: ffffffff8d659b80 > FS: 00000000014eb300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000055d7bf2b3138 CR3: 0000000014933000 CR4: 00000000001506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > __refcount_dec include/linux/refcount.h:344 [inline] > refcount_dec include/linux/refcount.h:359 [inline] > dev_put include/linux/netdevice.h:4135 [inline] > ip6gre_tunnel_uninit+0x3d7/0x440 net/ipv6/ip6_gre.c:420 > register_netdevice+0xadf/0x1500 net/core/dev.c:10308 > ip6gre_newlink_common.constprop.0+0x158/0x410 net/ipv6/ip6_gre.c:1984 > ip6gre_newlink+0x275/0x7a0 net/ipv6/ip6_gre.c:2017 > __rtnl_newlink+0x1062/0x1710 net/core/rtnetlink.c:3443 > rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3491 > rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5553 > netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502 > netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline] > netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338 > netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927 > sock_sendmsg_nosec net/socket.c:654 [inline] > sock_sendmsg+0xcf/0x120 net/socket.c:674 > ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350 > ___sys_sendmsg+0xf3/0x170 net/socket.c:2404 > __sys_sendmsg+0xe5/0x1b0 net/socket.c:2433 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > > Fixes: 919067cc845f ("net: add CONFIG_PCPU_DEV_REFCNT") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Reported-by: syzbot <syzkaller@googlegroups.com> > Signed-off-by: David S. Miller <davem@davemloft.net> > (backported from commit 7f700334be9aeb91d5d86ef9ad2d901b9b453e9b) > [cascardo: there is no ip6gre_tap_init] > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> > --- > net/ipv6/ip6_gre.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c > index dc9947bed6b8..7c01ac4b8726 100644 > --- a/net/ipv6/ip6_gre.c > +++ b/net/ipv6/ip6_gre.c > @@ -1111,6 +1111,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev) > > ip6gre_tnl_init_features(dev); > > + dev_hold(dev); > return 0; > } > > @@ -1440,8 +1441,6 @@ static int ip6gre_newlink_common(struct net *src_net, struct net_device *dev, > if (tb[IFLA_MTU]) > ip6_tnl_change_mtu(dev, nla_get_u32(tb[IFLA_MTU])); > > - dev_hold(dev); > - > out: > return err; > }
On 08.04.22 15:56, Thadeu Lima de Souza Cascardo wrote: > From: Eric Dumazet <edumazet@google.com> > > BugLink: https://bugs.launchpad.net/bugs/1968340 > > After adopting CONFIG_PCPU_DEV_REFCNT=n option, syzbot was able to trigger > a warning [1] > > Issue here is that: > > - all dev_put() should be paired with a corresponding dev_hold(), > and vice versa. > > - A driver doing a dev_put() in its ndo_uninit() MUST also > do a dev_hold() in its ndo_init(), only when ndo_init() > is returning 0. > > Otherwise, register_netdevice() would call ndo_uninit() > in its error path and release a refcount too soon. > > ip6_gre for example (among others problematic drivers) > has to use dev_hold() in ip6gre_tunnel_init_common() > instead of from ip6gre_newlink_common(), covering > both ip6gre_tunnel_init() and ip6gre_tap_init()/ > > Note that ip6gre_tunnel_init_common() is not called from > ip6erspan_tap_init() thus we also need to add a dev_hold() there, > as ip6erspan_tunnel_uninit() does call dev_put() > > [1] > refcount_t: decrement hit 0; leaking memory. > WARNING: CPU: 0 PID: 8422 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31 > Modules linked in: > CPU: 1 PID: 8422 Comm: syz-executor854 Not tainted 5.12.0-rc4-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31 > Code: 1d 6a 5a e8 09 31 ff 89 de e8 8d 1a ab fd 84 db 75 e0 e8 d4 13 ab fd 48 c7 c7 a0 e1 c1 89 c6 05 4a 5a e8 09 01 e8 2e 36 fb 04 <0f> 0b eb c4 e8 b8 13 ab fd 0f b6 1d 39 5a e8 09 31 ff 89 de e8 58 > RSP: 0018:ffffc900018befd0 EFLAGS: 00010282 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 > RDX: ffff88801ef19c40 RSI: ffffffff815c51f5 RDI: fffff52000317dec > RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 > R10: ffffffff815bdf8e R11: 0000000000000000 R12: ffff888018cf4568 > R13: ffff888018cf4c00 R14: ffff8880228f2000 R15: ffffffff8d659b80 > FS: 00000000014eb300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000055d7bf2b3138 CR3: 0000000014933000 CR4: 00000000001506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > __refcount_dec include/linux/refcount.h:344 [inline] > refcount_dec include/linux/refcount.h:359 [inline] > dev_put include/linux/netdevice.h:4135 [inline] > ip6gre_tunnel_uninit+0x3d7/0x440 net/ipv6/ip6_gre.c:420 > register_netdevice+0xadf/0x1500 net/core/dev.c:10308 > ip6gre_newlink_common.constprop.0+0x158/0x410 net/ipv6/ip6_gre.c:1984 > ip6gre_newlink+0x275/0x7a0 net/ipv6/ip6_gre.c:2017 > __rtnl_newlink+0x1062/0x1710 net/core/rtnetlink.c:3443 > rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3491 > rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5553 > netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502 > netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline] > netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338 > netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927 > sock_sendmsg_nosec net/socket.c:654 [inline] > sock_sendmsg+0xcf/0x120 net/socket.c:674 > ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350 > ___sys_sendmsg+0xf3/0x170 net/socket.c:2404 > __sys_sendmsg+0xe5/0x1b0 net/socket.c:2433 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > > Fixes: 919067cc845f ("net: add CONFIG_PCPU_DEV_REFCNT") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Reported-by: syzbot <syzkaller@googlegroups.com> > Signed-off-by: David S. Miller <davem@davemloft.net> > (backported from commit 7f700334be9aeb91d5d86ef9ad2d901b9b453e9b) > [cascardo: there is no ip6gre_tap_init] > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Acked-by: Stefan Bader <stefan.bader@canonical.com> > --- > net/ipv6/ip6_gre.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c > index dc9947bed6b8..7c01ac4b8726 100644 > --- a/net/ipv6/ip6_gre.c > +++ b/net/ipv6/ip6_gre.c > @@ -1111,6 +1111,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev) > > ip6gre_tnl_init_features(dev); > > + dev_hold(dev); > return 0; > } > > @@ -1440,8 +1441,6 @@ static int ip6gre_newlink_common(struct net *src_net, struct net_device *dev, > if (tb[IFLA_MTU]) > ip6_tnl_change_mtu(dev, nla_get_u32(tb[IFLA_MTU])); > > - dev_hold(dev); > - > out: > return err; > }
Applied to bionic:linux/master-next. Thanks. -Zack On 4/8/22 9:56 AM, Thadeu Lima de Souza Cascardo wrote: > From: Eric Dumazet <edumazet@google.com> > > BugLink: https://bugs.launchpad.net/bugs/1968340 > > After adopting CONFIG_PCPU_DEV_REFCNT=n option, syzbot was able to trigger > a warning [1] > > Issue here is that: > > - all dev_put() should be paired with a corresponding dev_hold(), > and vice versa. > > - A driver doing a dev_put() in its ndo_uninit() MUST also > do a dev_hold() in its ndo_init(), only when ndo_init() > is returning 0. > > Otherwise, register_netdevice() would call ndo_uninit() > in its error path and release a refcount too soon. > > ip6_gre for example (among others problematic drivers) > has to use dev_hold() in ip6gre_tunnel_init_common() > instead of from ip6gre_newlink_common(), covering > both ip6gre_tunnel_init() and ip6gre_tap_init()/ > > Note that ip6gre_tunnel_init_common() is not called from > ip6erspan_tap_init() thus we also need to add a dev_hold() there, > as ip6erspan_tunnel_uninit() does call dev_put() > > [1] > refcount_t: decrement hit 0; leaking memory. > WARNING: CPU: 0 PID: 8422 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31 > Modules linked in: > CPU: 1 PID: 8422 Comm: syz-executor854 Not tainted 5.12.0-rc4-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31 > Code: 1d 6a 5a e8 09 31 ff 89 de e8 8d 1a ab fd 84 db 75 e0 e8 d4 13 ab fd 48 c7 c7 a0 e1 c1 89 c6 05 4a 5a e8 09 01 e8 2e 36 fb 04 <0f> 0b eb c4 e8 b8 13 ab fd 0f b6 1d 39 5a e8 09 31 ff 89 de e8 58 > RSP: 0018:ffffc900018befd0 EFLAGS: 00010282 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 > RDX: ffff88801ef19c40 RSI: ffffffff815c51f5 RDI: fffff52000317dec > RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 > R10: ffffffff815bdf8e R11: 0000000000000000 R12: ffff888018cf4568 > R13: ffff888018cf4c00 R14: ffff8880228f2000 R15: ffffffff8d659b80 > FS: 00000000014eb300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000055d7bf2b3138 CR3: 0000000014933000 CR4: 00000000001506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > __refcount_dec include/linux/refcount.h:344 [inline] > refcount_dec include/linux/refcount.h:359 [inline] > dev_put include/linux/netdevice.h:4135 [inline] > ip6gre_tunnel_uninit+0x3d7/0x440 net/ipv6/ip6_gre.c:420 > register_netdevice+0xadf/0x1500 net/core/dev.c:10308 > ip6gre_newlink_common.constprop.0+0x158/0x410 net/ipv6/ip6_gre.c:1984 > ip6gre_newlink+0x275/0x7a0 net/ipv6/ip6_gre.c:2017 > __rtnl_newlink+0x1062/0x1710 net/core/rtnetlink.c:3443 > rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3491 > rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5553 > netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502 > netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline] > netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338 > netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927 > sock_sendmsg_nosec net/socket.c:654 [inline] > sock_sendmsg+0xcf/0x120 net/socket.c:674 > ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350 > ___sys_sendmsg+0xf3/0x170 net/socket.c:2404 > __sys_sendmsg+0xe5/0x1b0 net/socket.c:2433 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > > Fixes: 919067cc845f ("net: add CONFIG_PCPU_DEV_REFCNT") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Reported-by: syzbot <syzkaller@googlegroups.com> > Signed-off-by: David S. Miller <davem@davemloft.net> > (backported from commit 7f700334be9aeb91d5d86ef9ad2d901b9b453e9b) > [cascardo: there is no ip6gre_tap_init] > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> > --- > net/ipv6/ip6_gre.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c > index dc9947bed6b8..7c01ac4b8726 100644 > --- a/net/ipv6/ip6_gre.c > +++ b/net/ipv6/ip6_gre.c > @@ -1111,6 +1111,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev) > > ip6gre_tnl_init_features(dev); > > + dev_hold(dev); > return 0; > } > > @@ -1440,8 +1441,6 @@ static int ip6gre_newlink_common(struct net *src_net, struct net_device *dev, > if (tb[IFLA_MTU]) > ip6_tnl_change_mtu(dev, nla_get_u32(tb[IFLA_MTU])); > > - dev_hold(dev); > - > out: > return err; > }
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index dc9947bed6b8..7c01ac4b8726 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -1111,6 +1111,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev) ip6gre_tnl_init_features(dev); + dev_hold(dev); return 0; } @@ -1440,8 +1441,6 @@ static int ip6gre_newlink_common(struct net *src_net, struct net_device *dev, if (tb[IFLA_MTU]) ip6_tnl_change_mtu(dev, nla_get_u32(tb[IFLA_MTU])); - dev_hold(dev); - out: return err; }