On Mon, 2010-05-31 at 19:19 +0200, Thomas Gleixner wrote: > On Mon, 31 May 2010, James Bottomley wrote: > > On Mon, 2010-05-31 at 18:43 +0200, Thomas Gleixner wrote: > > > On Mon, 31 May 2010, James Bottomley wrote: > > > > > > > On Mon, 2010-05-31 at 10:03 -0400, Tedheadster wrote: > > > > > I'm reliably getting this oops: > > > > > > > > > > Configuring Adaptec (SCSI-ID 6) at IO:334, IRQ 10, DMA priority 6 > > > > > BUG: sleeping function called from invalid context at mm/slub.c:1598 > > > > > in_atomic(): 0, irqs_disabled(): 1, pid: 4782, name: modprobe > > > > > Pid: 4782, comm: modprobe Not tainted 2.6.30.10-105.2.23.RODATA.fc11.i586 #1 > > > > > Call Trace: > > > > > [<c0469e58>] ? request_threaded_irq+0x85/0x145 > > > > > [<c0422ab7>] __might_sleep+0xc4/0xc9 > > > > > [<c04a4322>] kmem_cache_alloc_notrace+0x29/0xb0 > > > > > [<c0469e58>] request_threaded_irq+0x85/0x145 > > > > > [<d086439c>] ? do_aha1542_intr_handle+0x0/0x2be [aha1542] > > > > > [<d08696aa>] aha1542_detect+0x631/0x76f [aha1542] > > > > > [<d0869841>] init_this_scsi_driver+0x59/0xc7 [aha1542] > > > > > [<d08697e8>] ? init_this_scsi_driver+0x0/0xc7 [aha1542] > > > > > [<c040114b>] do_one_initcall+0x51/0x13f > > > > > [<c0451111>] sys_init_module+0x8b/0x192 > > > > > [<c0403535>] syscall_call+0x7/0xb > > > > > scsi5 : Adaptec 1542 > > > > > > > > So this one's a bit tricky. aha1542 uses a global spinlock to give it > > > > thread safety and various other things. In this case it's trying to use > > > > the lock to hold off the interrupt until everything is set up. > > > > > > > > Now that we're doing a GFP_KERNEL allocation in the interrupt handler > > > > code you can't disable interrupts while calling request_irq since this > > > > is an old card liable to spurious interrupts as it gets poked in setup. > > > > > > > > I think a possible solution is this, since the mere act of installing an > > > > interrupt handler shouldn't trigger the problem. > > > > > > > > However, I thought the pattern of disabling interrupts and setting up > > > > the handler and registers was a common one ... is there some way this is > > > > supposed to work now that doesn't involve altering the drivers? > > > > > > Most drivers do the sane thing: > > > > > > Disable interrupts at the device level > > > Install handler via request_irq() > > > Setup stuff > > > Enable interrupts at the device level > > > > That only works for some hardware ... a lot of older hardware can't > > disable interrupts; the best you can do is to have the box physically > > not listening to the line. > > > > > So no, there is no way this is supposed to work with drivers which > > > don't follow that simple scheme. > > > > > > commit 0e43785c5 (irq: use GFP_KERNEL for action allocation in > > > request_irq()) changed that particular instance to GFP_KERNEL because > > > the request_irq code calls (and always did) code which cannot be > > > called in atomic contexts, e.g. the proc entry handling. > > > > So, like I said, I think we can install the handler without tickling the > > hardware. Ideally we'd like to install it IRQ_DISABLED and then call > > enable_irq after we're done with the setup, but that doesn't seem to be > > possible. > > We have a mechanism in place to do that, but it's not available for > drivers yet. If that's really a requirement, then we can make it > available with very little effort, but that does not resolve the > problem when the interrupt is shared and the interrupt line is already > enabled. Heh, well having this problem is usually a reason the driver disallows interrupt sharing. Like I said, I don't see a reason why installing the handler would trigger the interrupt, so lets try just moving the lock first. I'd only need the install disabled if I weren't disabling interrupts during setup, which would be nice, but not necessary since this driver is coded to do that already. James -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
