ipv6: fix a BUG in rt6_get_pcpu_route()
Ido reported following splat and provided a patch. [ 122.221814] BUG: using smp_processor_id() in preemptible [00000000] code: sshd/2672 [ 122.221845] caller is debug_smp_processor_id+0x17/0x20 [ 122.221866] CPU: 0 PID: 2672 Comm: sshd Not tainted 4.14.0-rc3-idosch-next-custom #639 [ 122.221880] Hardware name: Mellanox Technologies Ltd. MSN2100-CB2FO/SA001017, BIOS 5.6.5 06/07/2016 [ 122.221893] Call Trace: [ 122.221919] dump_stack+0xb1/0x10c [ 122.221946] ? _atomic_dec_and_lock+0x124/0x124 [ 122.221974] ? ___ratelimit+0xfe/0x240 [ 122.222020] check_preemption_disabled+0x173/0x1b0 [ 122.222060] debug_smp_processor_id+0x17/0x20 [ 122.222083] ip6_pol_route+0x1482/0x24a0 ... I believe we can simplify this code path a bit, since we no longer hold a read_lock and need to release it to avoid a dead lock. By disabling BH, we make sure we'll prevent code re-entry and rt6_get_pcpu_route()/rt6_make_pcpu_route() run on the same cpu. Fixes: 66f5d6ce ("ipv6: replace rwlock with rcu and spinlock in fib6_table") Reported-by:Ido Schimmel <idosch@mellanox.com> Signed-off-by:
Eric Dumazet <edumazet@google.com> Tested-by:
Ido Schimmel <idosch@mellanox.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
51a0c00c
Please register or sign in to comment