725a97e43e
I run into something declaring itself as "spinlock deadlock", BUG: spinlock lockup on CPU#1, kjournald/27816, ffff88000ad6bca0 Pid: 27816, comm: kjournald Tainted: G W 2.6.34.6 #2 Call Trace: <IRQ> [<ffffffff811ba0aa>] do_raw_spin_lock+0x11e/0x14d [<ffffffff81340fde>] _raw_spin_lock_irqsave+0x6a/0x81 [<ffffffff8103b694>] ? __wake_up+0x22/0x50 [<ffffffff8103b694>] __wake_up+0x22/0x50 [<ffffffffa07ff661>] bm_async_io_complete+0x258/0x299 [drbd] but the call traces do not fit at all, all other cpus are cpu_idle. I think it may be this race: drbd_bm_write_page wait_queue_head_t io_wait; atomic_t in_flight; bm_async_io submit_bio bm_async_io_complete if (atomic_dec_and_test(in_flight)) wait_event(io_wait, atomic_read(in_flight) == 0) return wake_up(io_wait) The wake_up now accesses the wait_queue_head_t spinlock, which is no longer valid, since the stack frame of drbd_bm_write_page has been clobbered now. Fix this by using struct completion, which does both the condition test as well as the wake_up inside its spinlock, so this race cannot happen. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> |
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| .. | ||
| drbd_actlog.c | ||
| drbd_bitmap.c | ||
| drbd_int.h | ||
| drbd_main.c | ||
| drbd_nl.c | ||
| drbd_proc.c | ||
| drbd_receiver.c | ||
| drbd_req.c | ||
| drbd_req.h | ||
| drbd_strings.c | ||
| drbd_vli.h | ||
| drbd_worker.c | ||
| drbd_wrappers.h | ||
| Kconfig | ||
| Makefile | ||