Messages in this thread | | | Date | Mon, 14 Dec 2009 21:52:33 +0100 | From | Frederic Weisbecker <> | Subject | Re: packet_sendmsg_spkt sleeping from invalid context |
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On Mon, Dec 14, 2009 at 08:24:23PM +0100, Eric Dumazet wrote: > Le 14/12/2009 18:52, Frederic Weisbecker a écrit : > > Hi, > > > > I don't know if it has been reported already. > > I get the following warning on boot, with latest upstream tree: > > > > [ 32.776502] sched: BUG: sleeping function called from invalid context at mm/slab.c:3032 > > [ 32.802173] sched: in_atomic(): 1, irqs_disabled(): 0, pid: 3555, name: dhclient3 > > [ 32.821141] 1 lock held by dhclient3/3555: > > [ 32.821147] #0: (rcu_read_lock){.+.+.+}, at: [<ffffffff815d177d>] packet_sendmsg_spkt+0x7d/0x2c0 > > [ 32.821174] Pid: 3555, comm: dhclient3 Tainted: G W 2.6.32-tip+ #134 > > [ 32.821181] Call Trace: > > [ 32.821194] [<ffffffff810811c3>] ? __debug_show_held_locks+0x13/0x30 > > [ 32.821207] [<ffffffff8103d6b8>] __might_sleep+0x118/0x140 > > [ 32.821219] [<ffffffff81110c23>] kmem_cache_alloc+0x173/0x190 > > [ 32.821231] [<ffffffff815483d9>] __alloc_skb+0x49/0x170 > > [ 32.821241] [<ffffffff81542238>] sock_wmalloc+0x38/0x80 > > [ 32.821250] [<ffffffff815d182b>] packet_sendmsg_spkt+0x12b/0x2c0 > > [ 32.821260] [<ffffffff815d177d>] ? packet_sendmsg_spkt+0x7d/0x2c0 > > [ 32.821272] [<ffffffff8153ded7>] sock_sendmsg+0x127/0x140 > > [ 32.821285] [<ffffffff8106f4a0>] ? autoremove_wake_function+0x0/0x40 > > [ 32.821297] [<ffffffff810f467b>] ? might_fault+0x7b/0xd0 > > [ 32.821306] [<ffffffff810f467b>] ? might_fault+0x7b/0xd0 > > [ 32.821318] [<ffffffff815401aa>] ? move_addr_to_kernel+0x6a/0x70 > > [ 32.821328] [<ffffffff8154029f>] sys_sendto+0xef/0x120 > > [ 32.821340] [<ffffffff81131479>] ? mntput_no_expire+0x29/0x110 > > [ 32.821355] [<ffffffff810027db>] system_call_fastpath+0x16/0x1b > > > > Thanks for the report Frederic. > > We could partly revert the original commit, but as we wanted to avoid touching > device refcount, and af_packet might be the only real abuser, we could > try following patch instead. > > Thanks
I also wonder. Are you using PREEMPT_RCU ? That may explain why you haven't seen this issue because might_sleep() doesn't see you are in a rcu read locked section as preemption is not disabled, but it is illegal to voluntarily sleep in such area (although it's fine with preempt rcu) as doing so with non-prempt RCU config would barf.
I'm trying a patch to handle that.
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