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* [PATCH net] l2tp: fix race while getting PMTU on PPP pseudo-wire
@ 2014-09-03 12:12 Guillaume Nault
  2014-09-03 13:55 ` Eric Dumazet
  2014-09-05 21:41 ` David Miller
  0 siblings, 2 replies; 5+ messages in thread
From: Guillaume Nault @ 2014-09-03 12:12 UTC (permalink / raw)
  To: netdev; +Cc: James Chapman, David S. Miller

Use dst_entry held by sk_dst_get() to retrieve tunnel's PMTU.

The dst_mtu(__sk_dst_get(tunnel->sock)) call was racy. __sk_dst_get()
could return NULL if tunnel->sock->sk_dst_cache was reset just before the
call, thus making dst_mtu() dereference a NULL pointer:

[ 1937.661598] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
[ 1937.664005] IP: [<ffffffffa049db88>] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
[ 1937.664005] PGD daf0c067 PUD d9f93067 PMD 0
[ 1937.664005] Oops: 0000 [#1] SMP
[ 1937.664005] Modules linked in: l2tp_ppp l2tp_netlink l2tp_core ip6table_filter ip6_tables iptable_filter ip_tables ebtable_nat ebtables x_tables udp_tunnel pppoe pppox ppp_generic slhc deflate ctr twofish_generic twofish_x86_64_3way xts lrw gf128mul glue_helper twofish_x86_64 twofish_common blowfish_generic blowfish_x86_64 blowfish_common des_generic cbc xcbc rmd160 sha512_generic hmac crypto_null af_key xfrm_algo 8021q garp bridge stp llc tun atmtcp clip atm ext3 mbcache jbd iTCO_wdt coretemp kvm_intel iTCO_vendor_support kvm pcspkr evdev ehci_pci lpc_ich mfd_core i5400_edac edac_core i5k_amb shpchp button processor thermal_sys xfs crc32c_generic libcrc32c dm_mod usbhid sg hid sr_mod sd_mod cdrom crc_t10dif crct10dif_common ata_generic ahci ata_piix tg3 libahci libata uhci_hcd ptp ehci
 _hcd pps_core usbcore scsi_mod libphy usb_common [last unloaded: l2tp_core]
[ 1937.664005] CPU: 0 PID: 10022 Comm: l2tpstress Tainted: G           O   3.17.0-rc1 #1
[ 1937.664005] Hardware name: HP ProLiant DL160 G5, BIOS O12 08/22/2008
[ 1937.664005] task: ffff8800d8fda790 ti: ffff8800c43c4000 task.ti: ffff8800c43c4000
[ 1937.664005] RIP: 0010:[<ffffffffa049db88>]  [<ffffffffa049db88>] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
[ 1937.664005] RSP: 0018:ffff8800c43c7de8  EFLAGS: 00010282
[ 1937.664005] RAX: ffff8800da8a7240 RBX: ffff8800d8c64600 RCX: 000001c325a137b5
[ 1937.664005] RDX: 8c6318c6318c6320 RSI: 000000000000010c RDI: 0000000000000000
[ 1937.664005] RBP: ffff8800c43c7ea8 R08: 0000000000000000 R09: 0000000000000000
[ 1937.664005] R10: ffffffffa048e2c0 R11: ffff8800d8c64600 R12: ffff8800ca7a5000
[ 1937.664005] R13: ffff8800c439bf40 R14: 000000000000000c R15: 0000000000000009
[ 1937.664005] FS:  00007fd7f610f700(0000) GS:ffff88011a600000(0000) knlGS:0000000000000000
[ 1937.664005] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1937.664005] CR2: 0000000000000020 CR3: 00000000d9d75000 CR4: 00000000000027e0
[ 1937.664005] Stack:
[ 1937.664005]  ffffffffa049da80 ffff8800d8fda790 000000000000005b ffff880000000009
[ 1937.664005]  ffff8800daf3f200 0000000000000003 ffff8800c43c7e48 ffffffff81109b57
[ 1937.664005]  ffffffff81109b0e ffffffff8114c566 0000000000000000 0000000000000000
[ 1937.664005] Call Trace:
[ 1937.664005]  [<ffffffffa049da80>] ? pppol2tp_connect+0x235/0x41e [l2tp_ppp]
[ 1937.664005]  [<ffffffff81109b57>] ? might_fault+0x9e/0xa5
[ 1937.664005]  [<ffffffff81109b0e>] ? might_fault+0x55/0xa5
[ 1937.664005]  [<ffffffff8114c566>] ? rcu_read_unlock+0x1c/0x26
[ 1937.664005]  [<ffffffff81309196>] SYSC_connect+0x87/0xb1
[ 1937.664005]  [<ffffffff813e56f7>] ? sysret_check+0x1b/0x56
[ 1937.664005]  [<ffffffff8107590d>] ? trace_hardirqs_on_caller+0x145/0x1a1
[ 1937.664005]  [<ffffffff81213dee>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[ 1937.664005]  [<ffffffff8114c262>] ? spin_lock+0x9/0xb
[ 1937.664005]  [<ffffffff813092b4>] SyS_connect+0x9/0xb
[ 1937.664005]  [<ffffffff813e56d2>] system_call_fastpath+0x16/0x1b
[ 1937.664005] Code: 10 2a 84 81 e8 65 76 bd e0 65 ff 0c 25 10 bb 00 00 4d 85 ed 74 37 48 8b 85 60 ff ff ff 48 8b 80 88 01 00 00 48 8b b8 10 02 00 00 <48> 8b 47 20 ff 50 20 85 c0 74 0f 83 e8 28 89 83 10 01 00 00 89
[ 1937.664005] RIP  [<ffffffffa049db88>] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
[ 1937.664005]  RSP <ffff8800c43c7de8>
[ 1937.664005] CR2: 0000000000000020
[ 1939.559375] ---[ end trace 82d44500f28f8708 ]---

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
---
 net/l2tp/l2tp_ppp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 13752d9..b704a93 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -755,7 +755,8 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 	/* If PMTU discovery was enabled, use the MTU that was discovered */
 	dst = sk_dst_get(tunnel->sock);
 	if (dst != NULL) {
-		u32 pmtu = dst_mtu(__sk_dst_get(tunnel->sock));
+		u32 pmtu = dst_mtu(dst);
+
 		if (pmtu != 0)
 			session->mtu = session->mru = pmtu -
 				PPPOL2TP_HEADER_OVERHEAD;
-- 
2.1.0

^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH net] l2tp: fix race while getting PMTU on PPP pseudo-wire
  2014-09-03 12:12 [PATCH net] l2tp: fix race while getting PMTU on PPP pseudo-wire Guillaume Nault
@ 2014-09-03 13:55 ` Eric Dumazet
  2014-09-03 15:47   ` Guillaume Nault
  2014-09-05 21:47   ` Cong Wang
  2014-09-05 21:41 ` David Miller
  1 sibling, 2 replies; 5+ messages in thread
From: Eric Dumazet @ 2014-09-03 13:55 UTC (permalink / raw)
  To: Guillaume Nault, Dmitry Petukhov; +Cc: netdev, James Chapman, David S. Miller

On Wed, 2014-09-03 at 14:12 +0200, Guillaume Nault wrote:
> Use dst_entry held by sk_dst_get() to retrieve tunnel's PMTU.
> 
> The dst_mtu(__sk_dst_get(tunnel->sock)) call was racy. __sk_dst_get()
> could return NULL if tunnel->sock->sk_dst_cache was reset just before the
> call, thus making dst_mtu() dereference a NULL pointer:
> 
> [ 1937.661598] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
> [ 1937.664005] IP: [<ffffffffa049db88>] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
> [ 1937.664005] PGD daf0c067 PUD d9f93067 PMD 0
> [ 1937.664005] Oops: 0000 [#1] SMP
> [ 1937.664005] Modules linked in: l2tp_ppp l2tp_netlink l2tp_core ip6table_filter ip6_tables iptable_filter ip_tables ebtable_nat ebtables x_tables udp_tunnel pppoe pppox ppp_generic slhc deflate ctr twofish_generic twofish_x86_64_3way xts lrw gf128mul glue_helper twofish_x86_64 twofish_common blowfish_generic blowfish_x86_64 blowfish_common des_generic cbc xcbc rmd160 sha512_generic hmac crypto_null af_key xfrm_algo 8021q garp bridge stp llc tun atmtcp clip atm ext3 mbcache jbd iTCO_wdt coretemp kvm_intel iTCO_vendor_support kvm pcspkr evdev ehci_pci lpc_ich mfd_core i5400_edac edac_core i5k_amb shpchp button processor thermal_sys xfs crc32c_generic libcrc32c dm_mod usbhid sg hid sr_mod sd_mod cdrom crc_t10dif crct10dif_common ata_generic ahci ata_piix tg3 libahci libata uhci_hcd ptp eh
 ci_hcd pps_core usbcore scsi_mod libphy usb_common [last unloaded: l2tp_core]
> [ 1937.664005] CPU: 0 PID: 10022 Comm: l2tpstress Tainted: G           O   3.17.0-rc1 #1
> [ 1937.664005] Hardware name: HP ProLiant DL160 G5, BIOS O12 08/22/2008
> [ 1937.664005] task: ffff8800d8fda790 ti: ffff8800c43c4000 task.ti: ffff8800c43c4000
> [ 1937.664005] RIP: 0010:[<ffffffffa049db88>]  [<ffffffffa049db88>] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
> [ 1937.664005] RSP: 0018:ffff8800c43c7de8  EFLAGS: 00010282
> [ 1937.664005] RAX: ffff8800da8a7240 RBX: ffff8800d8c64600 RCX: 000001c325a137b5
> [ 1937.664005] RDX: 8c6318c6318c6320 RSI: 000000000000010c RDI: 0000000000000000
> [ 1937.664005] RBP: ffff8800c43c7ea8 R08: 0000000000000000 R09: 0000000000000000
> [ 1937.664005] R10: ffffffffa048e2c0 R11: ffff8800d8c64600 R12: ffff8800ca7a5000
> [ 1937.664005] R13: ffff8800c439bf40 R14: 000000000000000c R15: 0000000000000009
> [ 1937.664005] FS:  00007fd7f610f700(0000) GS:ffff88011a600000(0000) knlGS:0000000000000000
> [ 1937.664005] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> [ 1937.664005] CR2: 0000000000000020 CR3: 00000000d9d75000 CR4: 00000000000027e0
> [ 1937.664005] Stack:
> [ 1937.664005]  ffffffffa049da80 ffff8800d8fda790 000000000000005b ffff880000000009
> [ 1937.664005]  ffff8800daf3f200 0000000000000003 ffff8800c43c7e48 ffffffff81109b57
> [ 1937.664005]  ffffffff81109b0e ffffffff8114c566 0000000000000000 0000000000000000
> [ 1937.664005] Call Trace:
> [ 1937.664005]  [<ffffffffa049da80>] ? pppol2tp_connect+0x235/0x41e [l2tp_ppp]
> [ 1937.664005]  [<ffffffff81109b57>] ? might_fault+0x9e/0xa5
> [ 1937.664005]  [<ffffffff81109b0e>] ? might_fault+0x55/0xa5
> [ 1937.664005]  [<ffffffff8114c566>] ? rcu_read_unlock+0x1c/0x26
> [ 1937.664005]  [<ffffffff81309196>] SYSC_connect+0x87/0xb1
> [ 1937.664005]  [<ffffffff813e56f7>] ? sysret_check+0x1b/0x56
> [ 1937.664005]  [<ffffffff8107590d>] ? trace_hardirqs_on_caller+0x145/0x1a1
> [ 1937.664005]  [<ffffffff81213dee>] ? trace_hardirqs_on_thunk+0x3a/0x3f
> [ 1937.664005]  [<ffffffff8114c262>] ? spin_lock+0x9/0xb
> [ 1937.664005]  [<ffffffff813092b4>] SyS_connect+0x9/0xb
> [ 1937.664005]  [<ffffffff813e56d2>] system_call_fastpath+0x16/0x1b
> [ 1937.664005] Code: 10 2a 84 81 e8 65 76 bd e0 65 ff 0c 25 10 bb 00 00 4d 85 ed 74 37 48 8b 85 60 ff ff ff 48 8b 80 88 01 00 00 48 8b b8 10 02 00 00 <48> 8b 47 20 ff 50 20 85 c0 74 0f 83 e8 28 89 83 10 01 00 00 89
> [ 1937.664005] RIP  [<ffffffffa049db88>] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
> [ 1937.664005]  RSP <ffff8800c43c7de8>
> [ 1937.664005] CR2: 0000000000000020
> [ 1939.559375] ---[ end trace 82d44500f28f8708 ]---
> 
> Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
> ---
>  net/l2tp/l2tp_ppp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
> index 13752d9..b704a93 100644
> --- a/net/l2tp/l2tp_ppp.c
> +++ b/net/l2tp/l2tp_ppp.c
> @@ -755,7 +755,8 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
>  	/* If PMTU discovery was enabled, use the MTU that was discovered */
>  	dst = sk_dst_get(tunnel->sock);
>  	if (dst != NULL) {
> -		u32 pmtu = dst_mtu(__sk_dst_get(tunnel->sock));
> +		u32 pmtu = dst_mtu(dst);
> +
>  		if (pmtu != 0)
>  			session->mtu = session->mru = pmtu -
>  				PPPOL2TP_HEADER_OVERHEAD;


Probably introduced in commit f34c4a35d879 ("l2tp: take PMTU from tunnel
UDP socket")

CC Dmitry

Before this patch, the bug could not happen.

Acked-by: Eric Dumazet <edumazet@google.com>
Fixes: f34c4a35d879 ("l2tp: take PMTU from tunnel UDP socket")

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH net] l2tp: fix race while getting PMTU on PPP pseudo-wire
  2014-09-03 13:55 ` Eric Dumazet
@ 2014-09-03 15:47   ` Guillaume Nault
  2014-09-05 21:47   ` Cong Wang
  1 sibling, 0 replies; 5+ messages in thread
From: Guillaume Nault @ 2014-09-03 15:47 UTC (permalink / raw)
  To: Eric Dumazet; +Cc: Dmitry Petukhov, netdev, James Chapman, David S. Miller

On Wed, Sep 03, 2014 at 06:55:26AM -0700, Eric Dumazet wrote:
> On Wed, 2014-09-03 at 14:12 +0200, Guillaume Nault wrote:
> > Use dst_entry held by sk_dst_get() to retrieve tunnel's PMTU.
> > 
> > The dst_mtu(__sk_dst_get(tunnel->sock)) call was racy. __sk_dst_get()
> > could return NULL if tunnel->sock->sk_dst_cache was reset just before the
> > call, thus making dst_mtu() dereference a NULL pointer:
> > 
> > [ 1937.661598] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
> > [ 1937.664005] IP: [<ffffffffa049db88>] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
> > [ 1937.664005] PGD daf0c067 PUD d9f93067 PMD 0
> > [ 1937.664005] Oops: 0000 [#1] SMP
> > [ 1937.664005] Modules linked in: l2tp_ppp l2tp_netlink l2tp_core ip6table_filter ip6_tables iptable_filter ip_tables ebtable_nat ebtables x_tables udp_tunnel pppoe pppox ppp_generic slhc deflate ctr twofish_generic twofish_x86_64_3way xts lrw gf128mul glue_helper twofish_x86_64 twofish_common blowfish_generic blowfish_x86_64 blowfish_common des_generic cbc xcbc rmd160 sha512_generic hmac crypto_null af_key xfrm_algo 8021q garp bridge stp llc tun atmtcp clip atm ext3 mbcache jbd iTCO_wdt coretemp kvm_intel iTCO_vendor_support kvm pcspkr evdev ehci_pci lpc_ich mfd_core i5400_edac edac_core i5k_amb shpchp button processor thermal_sys xfs crc32c_generic libcrc32c dm_mod usbhid sg hid sr_mod sd_mod cdrom crc_t10dif crct10dif_common ata_generic ahci ata_piix tg3 libahci libata uhci_hcd ptp 
 ehci_hcd pps_core usbcore scsi_mod libphy usb_common [last unloaded: l2tp_core]
> > [ 1937.664005] CPU: 0 PID: 10022 Comm: l2tpstress Tainted: G           O   3.17.0-rc1 #1
> > [ 1937.664005] Hardware name: HP ProLiant DL160 G5, BIOS O12 08/22/2008
> > [ 1937.664005] task: ffff8800d8fda790 ti: ffff8800c43c4000 task.ti: ffff8800c43c4000
> > [ 1937.664005] RIP: 0010:[<ffffffffa049db88>]  [<ffffffffa049db88>] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
> > [ 1937.664005] RSP: 0018:ffff8800c43c7de8  EFLAGS: 00010282
> > [ 1937.664005] RAX: ffff8800da8a7240 RBX: ffff8800d8c64600 RCX: 000001c325a137b5
> > [ 1937.664005] RDX: 8c6318c6318c6320 RSI: 000000000000010c RDI: 0000000000000000
> > [ 1937.664005] RBP: ffff8800c43c7ea8 R08: 0000000000000000 R09: 0000000000000000
> > [ 1937.664005] R10: ffffffffa048e2c0 R11: ffff8800d8c64600 R12: ffff8800ca7a5000
> > [ 1937.664005] R13: ffff8800c439bf40 R14: 000000000000000c R15: 0000000000000009
> > [ 1937.664005] FS:  00007fd7f610f700(0000) GS:ffff88011a600000(0000) knlGS:0000000000000000
> > [ 1937.664005] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> > [ 1937.664005] CR2: 0000000000000020 CR3: 00000000d9d75000 CR4: 00000000000027e0
> > [ 1937.664005] Stack:
> > [ 1937.664005]  ffffffffa049da80 ffff8800d8fda790 000000000000005b ffff880000000009
> > [ 1937.664005]  ffff8800daf3f200 0000000000000003 ffff8800c43c7e48 ffffffff81109b57
> > [ 1937.664005]  ffffffff81109b0e ffffffff8114c566 0000000000000000 0000000000000000
> > [ 1937.664005] Call Trace:
> > [ 1937.664005]  [<ffffffffa049da80>] ? pppol2tp_connect+0x235/0x41e [l2tp_ppp]
> > [ 1937.664005]  [<ffffffff81109b57>] ? might_fault+0x9e/0xa5
> > [ 1937.664005]  [<ffffffff81109b0e>] ? might_fault+0x55/0xa5
> > [ 1937.664005]  [<ffffffff8114c566>] ? rcu_read_unlock+0x1c/0x26
> > [ 1937.664005]  [<ffffffff81309196>] SYSC_connect+0x87/0xb1
> > [ 1937.664005]  [<ffffffff813e56f7>] ? sysret_check+0x1b/0x56
> > [ 1937.664005]  [<ffffffff8107590d>] ? trace_hardirqs_on_caller+0x145/0x1a1
> > [ 1937.664005]  [<ffffffff81213dee>] ? trace_hardirqs_on_thunk+0x3a/0x3f
> > [ 1937.664005]  [<ffffffff8114c262>] ? spin_lock+0x9/0xb
> > [ 1937.664005]  [<ffffffff813092b4>] SyS_connect+0x9/0xb
> > [ 1937.664005]  [<ffffffff813e56d2>] system_call_fastpath+0x16/0x1b
> > [ 1937.664005] Code: 10 2a 84 81 e8 65 76 bd e0 65 ff 0c 25 10 bb 00 00 4d 85 ed 74 37 48 8b 85 60 ff ff ff 48 8b 80 88 01 00 00 48 8b b8 10 02 00 00 <48> 8b 47 20 ff 50 20 85 c0 74 0f 83 e8 28 89 83 10 01 00 00 89
> > [ 1937.664005] RIP  [<ffffffffa049db88>] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
> > [ 1937.664005]  RSP <ffff8800c43c7de8>
> > [ 1937.664005] CR2: 0000000000000020
> > [ 1939.559375] ---[ end trace 82d44500f28f8708 ]---
> > 
> > Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
> > ---
> >  net/l2tp/l2tp_ppp.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
> > index 13752d9..b704a93 100644
> > --- a/net/l2tp/l2tp_ppp.c
> > +++ b/net/l2tp/l2tp_ppp.c
> > @@ -755,7 +755,8 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
> >  	/* If PMTU discovery was enabled, use the MTU that was discovered */
> >  	dst = sk_dst_get(tunnel->sock);
> >  	if (dst != NULL) {
> > -		u32 pmtu = dst_mtu(__sk_dst_get(tunnel->sock));
> > +		u32 pmtu = dst_mtu(dst);
> > +
> >  		if (pmtu != 0)
> >  			session->mtu = session->mru = pmtu -
> >  				PPPOL2TP_HEADER_OVERHEAD;
> 
> 
> Probably introduced in commit f34c4a35d879 ("l2tp: take PMTU from tunnel
> UDP socket")
> 
Indeed, I forgot to mention it. Thanks for clarification.

> CC Dmitry
> 
> Before this patch, the bug could not happen.
> 
> Acked-by: Eric Dumazet <edumazet@google.com>
> Fixes: f34c4a35d879 ("l2tp: take PMTU from tunnel UDP socket")
> 
> 

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH net] l2tp: fix race while getting PMTU on PPP pseudo-wire
  2014-09-03 12:12 [PATCH net] l2tp: fix race while getting PMTU on PPP pseudo-wire Guillaume Nault
  2014-09-03 13:55 ` Eric Dumazet
@ 2014-09-05 21:41 ` David Miller
  1 sibling, 0 replies; 5+ messages in thread
From: David Miller @ 2014-09-05 21:41 UTC (permalink / raw)
  To: g.nault; +Cc: netdev, jchapman

From: Guillaume Nault <g.nault@alphalink.fr>
Date: Wed, 3 Sep 2014 14:12:55 +0200

> Use dst_entry held by sk_dst_get() to retrieve tunnel's PMTU.
> 
> The dst_mtu(__sk_dst_get(tunnel->sock)) call was racy. __sk_dst_get()
> could return NULL if tunnel->sock->sk_dst_cache was reset just before the
> call, thus making dst_mtu() dereference a NULL pointer:
 ...
> Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>

Applied and queued up for -stable, thanks!

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH net] l2tp: fix race while getting PMTU on PPP pseudo-wire
  2014-09-03 13:55 ` Eric Dumazet
  2014-09-03 15:47   ` Guillaume Nault
@ 2014-09-05 21:47   ` Cong Wang
  1 sibling, 0 replies; 5+ messages in thread
From: Cong Wang @ 2014-09-05 21:47 UTC (permalink / raw)
  To: Eric Dumazet
  Cc: Guillaume Nault, Dmitry Petukhov, netdev, James Chapman, David S. Miller

On Wed, Sep 3, 2014 at 6:55 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
>
>
> Probably introduced in commit f34c4a35d879 ("l2tp: take PMTU from tunnel
> UDP socket")
>
> CC Dmitry
>
> Before this patch, the bug could not happen.
>
> Acked-by: Eric Dumazet <edumazet@google.com>
> Fixes: f34c4a35d879 ("l2tp: take PMTU from tunnel UDP socket")

Probably it's the time to add "Fixes:" in netdev-FAQ.txt.

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2014-09-05 21:47 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-09-03 12:12 [PATCH net] l2tp: fix race while getting PMTU on PPP pseudo-wire Guillaume Nault
2014-09-03 13:55 ` Eric Dumazet
2014-09-03 15:47   ` Guillaume Nault
2014-09-05 21:47   ` Cong Wang
2014-09-05 21:41 ` David Miller

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