[EMAIL PROTECTED] wrote:
From: Ingo Molnar <[EMAIL PROTECTED]>
Barry K. Nathan reported the following lockdep warning:
[ 197.343948] BUG: warning at kernel/lockdep.c:1856/trace_hardirqs_on()
[ 197.345928] [<c010329b>] show_trace_log_lvl+0x5b/0x105
[ 197.346359] [<c0103896>] show_trace+0x1b/0x20
[ 197.346759] [<c01038ed>] dump_stack+0x1f/0x24
[ 197.347159] [<c012efa2>] trace_hardirqs_on+0xfb/0x185
[ 197.348873] [<c029b009>] _spin_unlock_irq+0x24/0x2d
[ 197.350620] [<e09034e8>] do_tx_done+0x171/0x179 [ns83820]
[ 197.350895] [<e090445c>] ns83820_irq+0x149/0x20b [ns83820]
[ 197.351166] [<c013b4b8>] handle_IRQ_event+0x1d/0x52
[ 197.353216] [<c013c6c2>] handle_level_irq+0x97/0xe1
[ 197.355157] [<c01048c3>] do_IRQ+0x8b/0xac
[ 197.355612] [<c0102d9d>] common_interrupt+0x25/0x2c
The driver's locking is definitely wrong, but I don't think this is the
fix, because PCI drivers with a single interrupt should be using
spin_lock() in the interrupt handler. Anything more would be uncivilized :)
/me starts to do a better patch...
Jesus, the locking here is awful. No wonder there are bugs.
Since this driver isn't seeing a ton of work these days, I think the
best thing to do would be to _simplify_ the locking. This driver is
grabbing so many locks, turning interrupts off+on so often that any
benefit the multiple locks had is probably long gone, particularly on
modern machines.
Let me see what I can do with it...
Jeff
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