path: root/lib
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authorSabrina Dubroca <sd@queasysnail.net>2015-02-26 05:35:41 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-05-06 21:56:28 +0200
commit9923e74aefabc4a73e572dc16e2999625885b1e7 (patch)
treecf67ee705940bb94abc9617109ec39503f300785 /lib
parent61ea92b94820a4728f6ad1316a22d9dc0b9b4289 (diff)
e1000: add dummy allocator to fix race condition between mtu change and netpoll
commit 08e8331654d1d7b2c58045e549005bc356aa7810 upstream. There is a race condition between e1000_change_mtu's cleanups and netpoll, when we change the MTU across jumbo size: Changing MTU frees all the rx buffers: e1000_change_mtu -> e1000_down -> e1000_clean_all_rx_rings -> e1000_clean_rx_ring Then, close to the end of e1000_change_mtu: pr_info -> ... -> netpoll_poll_dev -> e1000_clean -> e1000_clean_rx_irq -> e1000_alloc_rx_buffers -> e1000_alloc_frag And when we come back to do the rest of the MTU change: e1000_up -> e1000_configure -> e1000_configure_rx -> e1000_alloc_jumbo_rx_buffers alloc_jumbo finds the buffers already != NULL, since data (shared with page in e1000_rx_buffer->rxbuf) has been re-alloc'd, but it's garbage, or at least not what is expected when in jumbo state. This results in an unusable adapter (packets don't get through), and a NULL pointer dereference on the next call to e1000_clean_rx_ring (other mtu change, link down, shutdown): BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff81194d6e>] put_compound_page+0x7e/0x330 [...] Call Trace: [<ffffffff81195445>] put_page+0x55/0x60 [<ffffffff815d9f44>] e1000_clean_rx_ring+0x134/0x200 [<ffffffff815da055>] e1000_clean_all_rx_rings+0x45/0x60 [<ffffffff815df5e0>] e1000_down+0x1c0/0x1d0 [<ffffffff811e2260>] ? deactivate_slab+0x7f0/0x840 [<ffffffff815e21bc>] e1000_change_mtu+0xdc/0x170 [<ffffffff81647050>] dev_set_mtu+0xa0/0x140 [<ffffffff81664218>] do_setlink+0x218/0xac0 [<ffffffff814459e9>] ? nla_parse+0xb9/0x120 [<ffffffff816652d0>] rtnl_newlink+0x6d0/0x890 [<ffffffff8104f000>] ? kvm_clock_read+0x20/0x40 [<ffffffff810a2068>] ? sched_clock_cpu+0xa8/0x100 [<ffffffff81663802>] rtnetlink_rcv_msg+0x92/0x260 By setting the allocator to a dummy version, netpoll can't mess up our rx buffers. The allocator is set back to a sane value in e1000_configure_rx. Fixes: edbbb3ca1077 ("e1000: implement jumbo receive with partial descriptors") Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Aaron Brown <aaron.f.brown@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib')
0 files changed, 0 insertions, 0 deletions