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author | Nikolay Aleksandrov <nikolay@cumulusnetworks.com> | 2015-06-06 06:49:00 -0700 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-06-22 17:01:18 -0700 |
commit | 44da7386bb0bee83d2a11717e43730c27f4da717 (patch) | |
tree | 21b6893c9c10cf8289b3069ee16f1cb58ff89823 /net/bluetooth/hci_conn.c | |
parent | fa730505072b85750f21f652783bb595dc22bbd5 (diff) |
bridge: disable softirqs around br_fdb_update to avoid lockup
[ Upstream commit c4c832f89dc468cf11dc0dd17206bace44526651 ]
br_fdb_update() can be called in process context in the following way:
br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set)
so we need to disable softirqs because there are softirq users of the
hash_lock. One easy way to reproduce this is to modify the bridge utility
to set NTF_USE, enable stp and then set maxageing to a low value so
br_fdb_cleanup() is called frequently and then just add new entries in
a loop. This happens because br_fdb_cleanup() is called from timer/softirq
context. The spin locks in br_fdb_update were _bh before commit f8ae737deea1
("[BRIDGE]: forwarding remove unneeded preempt and bh diasables")
and at the time that commit was correct because br_fdb_update() couldn't be
called from process context, but that changed after commit:
292d1398983f ("bridge: add NTF_USE support")
Using local_bh_disable/enable around br_fdb_update() allows us to keep
using the spin_lock/unlock in br_fdb_update for the fast-path.
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Fixes: 292d1398983f ("bridge: add NTF_USE support")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/bluetooth/hci_conn.c')
0 files changed, 0 insertions, 0 deletions