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New: Cannot change MTU on bridged interface

Bugme-new Andrew Morton 2 participants 2 messages Jun 13, 2011 – Jun 14, 2011 1 message not in the archive

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Networking Network drivers Ethernet bridge
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Andrew Morton

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(switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface).

Quoted 18 lines · On Sat, 11 Jun 2011 10:59:18 GMT [email protected] wrote:

https://bugzilla.kernel.org/show_bug.cgi?id=37202

           Summary: Cannot change MTU on bridged interface
           Product: Networking
           Version: 2.5
    Kernel Version: 3.0.0-rc2
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Other
        AssignedTo: [email protected]
        ReportedBy: [email protected]
        Regression: No
Quoted 6 lines

Without bridge, setting mtu on eth0 works as expected. When eth0 is added to bridge 'br0' and this command is executed,

ip link set eth0 mtu 4000

results in:

erk.

Is this a new bug in 3.0-rc or have earlier kernels crashed in this manner?

Thanks.

Quoted 87 lines
Modules linked in: fuse ip6table_filter ip6_tables ebtable_nat ebtables bridge

stp llc sunrpc ipv6 kvm_intel kvm uinput snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_intel snd_hda_codec
snd_hwdep snd_seq i915 drm_kms_helper snd_seq_device drm iTCO_wdt i2c_algo_bit i2c_i801 ata_generic pata_acpi usblp i2c_core e1000e xhci_hcd video iTCO_vendor_support usb_storage snd_pcm se
rio_raw joydev pata_jmicron pcspkr microcode snd_timer snd soundcore snd_page_alloc [last unloaded: scsi_wait_scan]

Pid: 4247, comm: ip Not tainted 3.0.0-rc2 #4 Gigabyte Technology Co., Ltd. H57M-USB3/H57M-USB3

RIP: 0010:[<0000000000000000>]  [<          (null)>]           (null)
RSP: 0018:ffff8801e419d680  EFLAGS: 00010202
RAX: 0000000000000640 RBX: 0000000000000640 RCX: ffff880212874788
RDX: ffffffffa0347e00 RSI: ffffffffa0345c21 RDI: ffff880212874fb0
RBP: ffff8801e419d6a8 R08: 0000000000000000 R09: ffffffff81666030
R10: ffffffff81a7a3a0 R11: 0000000000000001 R12: ffff880212874000
R13: ffff880212874780 R14: 00000000ffffffea R15: ffffffffa00e4030
FS:  00007effa3ca6720(0000) GS:ffff88021fcc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000000 CR3: 00000001e401b000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process ip (pid: 4247, threadinfo ffff8801e419c000, task ffff8801f5f14560)
Stack:
 ffffffffa033b1a6 ffff880212874000 00000000ffffffed ffff8801f50af400
 ffff880211dc4000 ffff8801e419d6c8 ffffffff813ba810 0000000000000007
 ffff880212874780 ffff8801e419d6f8 ffffffffa033e2b4 ffff880211dc4000

Call Trace:
 [<ffffffffa033b1a6>] ? br_change_mtu+0x61/0x81 [bridge]
 [<ffffffff813ba810>] dev_set_mtu+0x45/0x75
 [<ffffffffa033e2b4>] br_device_event+0x7c/0x16c [bridge]
 [<ffffffff8146f921>] notifier_call_chain+0x37/0x63
 [<ffffffff8106d934>] raw_notifier_call_chain+0x14/0x16
 [<ffffffff813ba107>] call_netdevice_notifiers+0x4a/0x4f
 [<ffffffff813ba838>] dev_set_mtu+0x6d/0x75
 [<ffffffff813c8da2>] do_setlink+0x1ee/0x739
 [<ffffffff810e8052>] ? set_pte_at+0xe/0x12
 [<ffffffff8122e1de>] ? nla_parse+0x4f/0xc3
 [<ffffffff813c9f45>] rtnl_newlink+0x252/0x48d
 [<ffffffff813c9db7>] ? rtnl_newlink+0xc4/0x48d
 [<ffffffff8103d040>] ? need_resched+0x23/0x2d
 [<ffffffff813af3e3>] ? sock_rmalloc+0x33/0x95
 [<ffffffff813c9afe>] rtnetlink_rcv_msg+0x1eb/0x201
 [<ffffffff8103d040>] ? need_resched+0x23/0x2d
 [<ffffffff813c9913>] ? __rtnl_unlock+0x17/0x17
 [<ffffffff813dd9a8>] netlink_rcv_skb+0x45/0x90
 [<ffffffff813c94c4>] rtnetlink_rcv+0x26/0x2d
 [<ffffffff813dd4b3>] netlink_unicast+0xf1/0x15a
 [<ffffffff813dd7a1>] netlink_sendmsg+0x285/0x2a3
 [<ffffffff8110c558>] ? fatal_signal_pending+0x12/0x29
 [<ffffffff813a9e7d>] __sock_sendmsg+0x6a/0x76
 [<ffffffff813aa764>] sock_sendmsg+0xa8/0xc1
 [<ffffffff810cf7b0>] ? filemap_fault+0x20b/0x36c
 [<ffffffff810cde20>] ? unlock_page+0x2a/0x2f
 [<ffffffff810e8a1a>] ? __do_fault+0x34d/0x384
 [<ffffffff8103d040>] ? need_resched+0x23/0x2d
 [<ffffffff8103d058>] ? should_resched+0xe/0x2e
 [<ffffffff8103d040>] ? need_resched+0x23/0x2d
 [<ffffffff8103d058>] ? should_resched+0xe/0x2e
 [<ffffffff813b406e>] ? copy_from_user+0x2f/0x31
 [<ffffffff813b445e>] ? verify_iovec+0x54/0xa6
 [<ffffffff813aaa1a>] __sys_sendmsg+0x1ee/0x272
 [<ffffffff810eb570>] ? handle_mm_fault+0x149/0x15e
 [<ffffffff8146c5b6>] ? _raw_spin_lock+0xe/0x10
 [<ffffffff8146f8ab>] ? do_page_fault+0x321/0x360
 [<ffffffff810efda4>] ? do_brk+0x242/0x296
 [<ffffffff813ac02f>] sys_sendmsg+0x42/0x60
 [<ffffffff81472d42>] system_call_fastpath+0x16/0x1b
Code:  Bad RIP value.
RIP  [<          (null)>]           (null)
 RSP <ffff8801e419d680>
CR2: 0000000000000000
---[ end trace 29a99239194ab188 ]---

Bridge creation is managed by Fedora14 standard configs. eth0 is the only interface added to the bridge.

eth0 is
03:00.0 Ethernet controller [0200]: Intel Corporation 82574L Gigabit Network Connection [8086:10d3]
Subsystem: Intel Corporation Gigabit CT Desktop Adapter [8086:a01f] Kernel driver in use: e1000e
Kernel modules: e1000e

#2 lore raw

Andrew Morton wrote, at 06/14/2011 07:37 AM:

Quoted 29 lines

(switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface).

Quoted 22 lines · On Sat, 11 Jun 2011 10:59:18 GMT [email protected] wrote:

https://bugzilla.kernel.org/show_bug.cgi?id=37202

           Summary: Cannot change MTU on bridged interface
           Product: Networking
           Version: 2.5
    Kernel Version: 3.0.0-rc2
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Other
        AssignedTo: [email protected]
        ReportedBy: [email protected]
        Regression: No

Without bridge, setting mtu on eth0 works as expected. When eth0 is added to bridge 'br0' and this command is executed,

ip link set eth0 mtu 4000

This bug has been fixed.

commit 6407d74c5106bb362b4087693688afd34942b094

Author: Alexander Holler <[email protected]>
Date:   Tue Jun 7 00:51:35 2011 -0700

bridge: provide a cow_metrics method for fake_ops

Like in commit 0972ddb237 (provide cow_metrics() methods to blackhole dst_ops), we must provide a cow_metrics for bridges fake_dst_ops as well.

This fixes a regression coming from commits 62fa8a846d7d (net: Implement read-only protection and COW'ing of metrics.) and 33eb9873a28 (bridge:
initialize fake_rtable metrics)

ip link set mybridge mtu 1234

Signature · 3 lines
Best Regards
-----
Shan Wei