Hi Dipankar, Rusty, I seem to have found a race between RCU and rmmod. What I see appears to be an RCU destructor function that has a call pending but lives in a module, gets deleted before the RCU callback is processed:
RIP: 0010:[<ffffffff880329b7>] [<ffffffff880329b7>] RSP: 0018:ffffffff805a4f08 EFLAGS: 00010296 RAX: 0000000000000026 RBX: ffff81002fe53a38 RCX: 0000000000000026 RDX: ffff810001f730c0 RSI: 0000000000000001 RDI: 0000000000000002 RBP: ffffffff805a4f18 R08: 0000000000000002 R09: ffffffff80228eab R10: ffffffff805a4c98 R11: ffffffff805a4e28 R12: ffff81003979e140 R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffffffff80552000(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: ffffffff880329b7 CR3: 0000000000201000 CR4: 00000000000006e0 Process ksoftirqd/0 (pid: 3, threadinfo ffff81003e626000, task ffff810001f730c0) Stack: ffff81002fe53a38 ffff810001dc5040 ffffffff805a4f48 ffffffff8023946a ffff810001dc5140 0000000000000000 000000000000000a 0000000000000000 ffffffff805a4f58 ffffffff8023952c ffffffff805a4f78 ffffffff8022dca3 Call Trace: <IRQ> [<ffffffff8023946a>] __rcu_process_callbacks+0x15d/0x1fc [<ffffffff8023952c>] rcu_process_callbacks+0x23/0x44 [<ffffffff8022dca3>] tasklet_action+0x5e/0xb2 [<ffffffff8022db99>] __do_softirq+0x5f/0xe3 [<ffffffff8022daa9>] ksoftirqd+0x0/0x91 [<ffffffff8020a94c>] call_softirq+0x1c/0x28 <EOI> [<ffffffff8020c562>] do_softirq+0x39/0x9f [<ffffffff8022dafb>] ksoftirqd+0x52/0x91 [<ffffffff8023b79e>] kthread+0xd8/0x10e [<ffffffff8020a5d8>] child_rip+0xa/0x12 [<ffffffff8041b100>] _spin_unlock_irq+0x2b/0x31 [<ffffffff80209cec>] restore_args+0x0/0x30 [<ffffffff8023b6c6>] kthread+0x0/0x10e [<ffffffff8020a5ce>] child_rip+0x0/0x12 I think that rmmod needs to clear the RCU destructor queue, probably inside of __try_stop_module(). David - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
