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author | Julian Anastasov <ja@ssi.bg> | 2015-07-09 09:59:10 +0300 |
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committer | Ben Hutchings <ben@decadent.org.uk> | 2015-08-12 16:33:21 +0200 |
commit | 9191ab2f2b06b8f5ff9011a1b0fa62bd8adb7981 (patch) | |
tree | c3f4de612ded59a1040b2848ff17036b1d8ad5d0 /fs | |
parent | 78b6803a1961369d0b8350ff1f99b7375bbd7a8f (diff) | |
download | kernel_samsung_smdk4412-9191ab2f2b06b8f5ff9011a1b0fa62bd8adb7981.zip kernel_samsung_smdk4412-9191ab2f2b06b8f5ff9011a1b0fa62bd8adb7981.tar.gz kernel_samsung_smdk4412-9191ab2f2b06b8f5ff9011a1b0fa62bd8adb7981.tar.bz2 |
net: call rcu_read_lock early in process_backlog
commit 2c17d27c36dcce2b6bf689f41a46b9e909877c21 upstream.
Incoming packet should be either in backlog queue or
in RCU read-side section. Otherwise, the final sequence of
flush_backlog() and synchronize_net() may miss packets
that can run without device reference:
CPU 1 CPU 2
skb->dev: no reference
process_backlog:__skb_dequeue
process_backlog:local_irq_enable
on_each_cpu for
flush_backlog => IPI(hardirq): flush_backlog
- packet not found in backlog
CPU delayed ...
synchronize_net
- no ongoing RCU
read-side sections
netdev_run_todo,
rcu_barrier: no
ongoing callbacks
__netif_receive_skb_core:rcu_read_lock
- too late
free dev
process packet for freed dev
Fixes: 6e583ce5242f ("net: eliminate refcounting in backlog queue")
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2:
- Adjust context
- No need to rename the label in __netif_receive_skb()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs')
0 files changed, 0 insertions, 0 deletions