Re: 2.6.20-rc2-mm1 -- BUG: at arch/i386/mm/highmem.c:50 kmap_atomic()

[Jiri Slaby <jirislaby@gmail.com>]

Miles Lane wrote:
> On 12/18/06, Jiri Slaby <jirislaby@gmail.com> wrote:
>> Miles Lane wrote:
>> > On 12/18/06, Jiri Slaby <jirislaby@gmail.com> wrote:
>> >> Miles Lane wrote:
>> >> > Sorry, I am not finding who maintains highmem.  Please forward.
>> >> >
>> >> > WARNING (1) at arch/i386/mm/highmem.c:41 kmap_atomic()
>> >> > [<c0103c25>] dump_trace+0x68/0x1d2
>> >> > [<c0103da7>] show_trace_log_lvl+0x18/0x2c
>> >> > [<c0104410>] show_trace+0xf/0x11
>> >> > [<c010449b>] dump_stack+0x12/0x14
>> >> > [<c01144d9>] kmap_atomic+0x6f/0x1ca
>> >> > [<f930e25d>] ntfs_end_buffer_async_read+0x25d/0x2ca [ntfs]
>> >> > [<c017c294>] end_bio_bh_io_sync+0x2c/0x37
>> >> > [<c017dc29>] bio_endio+0x5a/0x62
>> >> > [<c01c8412>] __end_that_request_first+0x145/0x3ab
>> >> > [<c0237695>] ide_end_request+0x80/0xd8
>> >> > [<c023e3f0>] ide_dma_intr+0x55/0x9a
>> >> > [<c02388dc>] ide_intr+0x182/0x1f2
>> >> > [<c0140775>] handle_IRQ_event+0x1a/0x3f
>> >> > [<c0141baa>] handle_edge_irq+0xc6/0x11c
>> >> > [<c0105416>] do_IRQ+0x57/0x71
>> >> > [<c010366b>] common_interrupt+0x23/0x28
>> >> > [<f8826ee4>] acpi_processor_idle+0x1cc/0x36c [processor]
>> >> > [<c010132b>] cpu_idle+0x3e/0x6c
>> >> > [<c03f06d9>] start_kernel+0x2fa/0x2fe
>> >> > =======================
>> >>
>> >> Reported yet, you might see it here:
>> >> http://lkml.org/lkml/2006/12/15/222
>> >
>> > It is certainly very similar, and probably has the same root cause.
>> > Though, the trace isn't an exact match.   So, who should look into
>> > this?
>>
>> The trace needn't be the same. The problem was, that kmap_atomic
>> didn't know
>> KM_BIO_SRC_IRQ which is called (twice) from
>> ntfs_end_buffer_async_read. It
>> doesn't matter who called this ntfs function and why.

Oh sorry, my fault -- it does matter now: hardirq/softirq path.

> With 2.6.20-rc2-mm1 I am seeing:
> 
> BUG: at arch/i386/mm/highmem.c:50 kmap_atomic()
> [<c0114368>] kmap_atomic+0x8e/0x18b
> [<f938525d>] ntfs_end_buffer_async_read+0x25d/0x2ca [ntfs]
> [<c017a205>] end_bio_bh_io_sync+0x0/0x37
> [<c017a231>] end_bio_bh_io_sync+0x2c/0x37
> [<c017bb95>] bio_endio+0x5a/0x62
> [<c0237da2>] scsi_delete_timer+0xb/0x1b
> [<c01c641c>] __end_that_request_first+0x145/0x3ab
> [<c01cb657>] as_put_io_context+0x43/0x4e
> [<c0238ec7>] scsi_end_request+0x1d/0xb6
> [<c0239092>] scsi_io_completion+0xf5/0x2ba
> [<c011ff63>] do_timer+0x4fc/0x70c
> [<f90024b6>] sd_rw_intr+0x15d/0x186 [sd_mod]
> [<c023970f>] scsi_softirq_done+0x20/0xce
> [<c02358cd>] scsi_finish_command+0x3f/0x43
> [<c01c7f4c>] blk_done_softirq+0x4a/0x55
> [<c011c1d1>] __do_softirq+0x35/0x75
> [<c011c233>] do_softirq+0x22/0x26
> [<c011c3fa>] irq_exit+0x29/0x62
> [<c0106232>] do_IRQ+0x67/0x81
> [<c01046e3>] common_interrupt+0x23/0x28
> [<f8823ee4>] acpi_processor_idle+0x1cc/0x36c [processor]
> [<f8823d18>] acpi_processor_idle+0x0/0x36c [processor]
> [<c0102389>] cpu_idle+0x44/0x77
> [<c0380a93>] start_kernel+0x2f9/0x2fd
> [<c038042b>] unknown_bootoption+0x0/0x202

Yes, me too. But
type != KM_BIO_SRC_IRQ && type != KM_BIO_DST_IRQ) {
line appeared in in_irq() part in this kernel. This is OK for some cases -- when
it's called through hardirq path. softirq remains unresolved.

regards,
-- 
http://www.fi.muni.cz/~xslaby/            Jiri Slaby
faculty of informatics, masaryk university, brno, cz
e-mail: jirislaby gmail com, gpg pubkey fingerprint:
B674 9967 0407 CE62 ACC8  22A0 32CC 55C3 39D4 7A7E
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