Jens Axboe wrote: > On Wed, Jul 25 2007, Satyam Sharma wrote: >> On 7/23/07, Jens Axboe <jens.axboe@xxxxxxxxxx> wrote: >>> On Sun, Jul 22 2007, Satyam Sharma wrote: >>>> Hi Walter, >>>> >>>> Thanks for reporting this. >>>> >>>> On 7/22/07, walter harms <wharms@xxxxxx> wrote: >>>>> hello all, >>>>> on my asus notebook tm620 there is a crash with 2.6.22 and 2.6.21 >>>> Did this happen when you were resuming from a suspend-to-ram/disk? >>>> [ I ask because I see swsusp in the trace below, linux-pm added to Cc: ] >>>> >>>>> .... >>>>> Using IPI Shortcut mode >>>>> WARNING: at block/ll_rw_blk.c:1575 blk_remove_plug() >>>>> [<c01ac87e>] blk_remove_plug+0x36/0x5a >>>>> [<c01ac8b6>] __generic_unplug_device+0x14/0x1f >>>>> [<c01ad587>] __make_request+0x39b/0x49c >>>>> [<c01abc8c>] generic_make_request+0x228/0x255 >>>>> [<c01adb54>] submit_bio+0xa5/0xac >>>>> [<c013e233>] mempool_alloc+0x37/0xae >>>>> [<c01314dc>] submit+0xc2/0x11d >>>>> [<c0131585>] bio_read_page+0x24/0x27 >>>>> [<c013188b>] swsusp_check+0x4f/0xaf >>>>> [<c012f6c2>] software_resume+0x5f/0x108 >>>>> [<c037867e>] kernel_init+0xb0/0x212 >>>>> [<c0103a16>] ret_from_fork+0x6/0x1c >>>>> [<c03785ce>] kernel_init+0x0/0x212 >>>>> [<c03785ce>] kernel_init+0x0/0x212 >>>>> [<c010465b>] kernel_thread_helper+0x7/0x10 >>>>> ======================= >>>> Surprising, that's a WARN_ON(!irqs_disabled()) but IRQs are disabled >>>> alright on that codepath. OTOH, __make_request() is heavily goto-driven, >>>> uses the non-save/restore variants of spin_lock_irq, and does not even >>>> balance locks / unlocks for some error paths ... gaah. >>> __make_request() must be called from process context, hence >>> spin_lock_irq() is perfectly already and the fastest way to go. And of >>> course the locking is balanced! So please save your 'gaah's for code >>> you actually took the time to try and understand. >> You're right, I didn't really look at that code for long (it even >> explicitly >> comments about what's going with the locking in there!) sorry about >> that. >> >> [ Off-topic: BTW does every call to __make_request() end up in >> blk_remove_plug()? Since you're explicitly making the assumption >> that it *must* be called from process context (and hence the use of >> the non-save/restore variants), you could consider putting a >> WARN_ON(irqs_disabled()) over there, and perhaps a WARN_ON >> (!spin_is_locked(queue_lock)) in blk_remove_plug() instead, and >> other such similar functions that currently have the !irqs_disabled >> check. This way you'd effectively cover _both_ the assertions, >> and in appropriate places -- just a suggestion. ] > > No, blk_remove_plug() will only be called for sync bios, or where we > have to wait for request allocation (which will unplug the device). > > __generic_make_request() already does a might_sleep() check, so it > should catch this already. > >>> But it does look like unbalanced irq disable/enable calls. I'd guess in >>> the suspend/resume path. Obviously something more esoteric, since this >>> is the first such report for 2.6.22, so like some not-very-used driver >>> for instance. >> Now that I do look at the codepath, it does seem surprising irqs were >> not disabled there. There are a bunch of calls to _other_ functions >> between the spin_lock_irq and the blk_remove_plug via >> __generic_unplug_device that would also have complained about >> !irqs_disabled. >> >> Walter, does this happen reproducibly? > > As I previously wrote, it's like some of the device power up or resume > routines that botch the irq enable/disable stuff. It'd be interesting to > start stripping down the config until the warning goes away - or enable > CONFIG_PM_DEBUG which may help as well. > i will give CONFIG_PM_DEBUG a try, do not expect results before WE. re, wh _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
