Change locking surrounding kmap_atomic from local_irqsave to
local_irqsave_nort. This fixes issues with PREEMPT_RT.
Signed-off-by: Jakub Jozwicki <[email protected]>
--- linux-2.6.25.10/drivers/ata/libata-core.c 2008-07-03 05:46:47.000000000
+0200
+++ linux-2.6.25.10-rt7/drivers/ata/libata-core.c 2008-07-12
23:59:33.132140258 +0200
@@ -5157,14 +5157,14 @@
unsigned long flags;
/* FIXME: use a bounce buffer */
- local_irq_save(flags);
+ local_irq_save_nort(flags);
buf = kmap_atomic(page, KM_IRQ0);
/* do the actual data transfer */
ap->ops->data_xfer(qc->dev, buf + offset, qc->sect_size, do_write);
kunmap_atomic(buf, KM_IRQ0);
- local_irq_restore(flags);
+ local_irq_restore_nort(flags);
} else {
buf = page_address(page);
ap->ops->data_xfer(qc->dev, buf + offset, qc->sect_size, do_write);
@@ -5294,14 +5294,14 @@
unsigned long flags;
/* FIXME: use bounce buffer */
- local_irq_save(flags);
+ local_irq_save_nort(flags);
buf = kmap_atomic(page, KM_IRQ0);
/* do the actual data transfer */
consumed = ap->ops->data_xfer(dev, buf + offset, count, rw);
kunmap_atomic(buf, KM_IRQ0);
- local_irq_restore(flags);
+ local_irq_restore_nort(flags);
} else {
buf = page_address(page);
consumed = ap->ops->data_xfer(dev, buf + offset, count, rw);
On Sun, 13 Jul 2008 01:27:36 +0200 "Jakub W. Jozwicki" <[email protected]> wrote:
> Change locking surrounding kmap_atomic from local_irqsave to
> local_irqsave_nort. This fixes issues with PREEMPT_RT.
>
I assume this is a -rt kernel patch.
>
> --- linux-2.6.25.10/drivers/ata/libata-core.c 2008-07-03 05:46:47.000000000
> +0200
> +++ linux-2.6.25.10-rt7/drivers/ata/libata-core.c 2008-07-12
> 23:59:33.132140258 +0200
> @@ -5157,14 +5157,14 @@
> unsigned long flags;
>
> /* FIXME: use a bounce buffer */
> - local_irq_save(flags);
> + local_irq_save_nort(flags);
eww. If we're going to have to do stuff like this in mainline then
there might be a revolt.
On Sun, 13 Jul 2008 01:27:36 +0200
"Jakub W. Jozwicki" <[email protected]> wrote:
> Change locking surrounding kmap_atomic from local_irqsave to
> local_irqsave_nort. This fixes issues with PREEMPT_RT.
>
> Signed-off-by: Jakub Jozwicki <[email protected]>
The right way to fix this is to use a bounce buffer. I sent Jeff patches
to do that a couple of times. I'm not sure what has happened to them
since ? So NAK this, we should apply the patch to actually fix the bug
instead.
Jeff ?
Alan
Sunday, 13 of July 2008 12:25:43 Alan Cox napisał(a):
> On Sun, 13 Jul 2008 01:27:36 +0200
>
> "Jakub W. Jozwicki" <[email protected]> wrote:
> > Change locking surrounding kmap_atomic from local_irqsave to
> > local_irqsave_nort. This fixes issues with PREEMPT_RT.
> >
> > Signed-off-by: Jakub Jozwicki <[email protected]>
>
> The right way to fix this is to use a bounce buffer. I sent Jeff patches
> to do that a couple of times. I'm not sure what has happened to them
> since ? So NAK this, we should apply the patch to actually fix the bug
> instead.
>
> Jeff ?
>
> Alan
Sent patch was for:
[ 16.787021] BUG: sleeping function called from invalid context IRQ-14(5730)
at arch/x86/mm/highmem_32.c:8
[ 16.787021] in_atomic():0 [00000000], irqs_disabled():1
[ 16.787021] Pid: 5730, comm: IRQ-14 Not tainted 2.6.25.10-rtXXX #12
[ 16.787021] [<c0120fc4>] __might_sleep+0xf1/0xf8
[ 16.787021] [<c011c035>] kmap+0x47/0x5a
[ 16.787021] [<c03442b2>] ata_scsi_rbuf_get+0x23/0x31
[ 16.787021] [<c0345975>] atapi_qc_complete+0x252/0x2c5
[ 16.787021] [<c012edee>] ? irq_exit+0x7b/0x7e
[ 16.787021] [<c0109727>] ? do_IRQ+0x6e/0x87
[ 16.787021] [<c033d041>] __ata_qc_complete+0x8e/0x93
[ 16.787021] [<c033ddfb>] ata_qc_complete+0x182/0x188
[ 16.787021] [<c033e188>] ata_hsm_qc_complete+0xa1/0xa5
[ 16.787021] [<c033e8fd>] ata_hsm_move+0x5dd/0x628
[ 16.787021] [<c0342f76>] ata_interrupt+0x14e/0x1cb
[ 16.787021] [<c015c72c>] handle_IRQ_event+0x4e/0xd1
[ 16.787021] [<c015d266>] do_irqd+0x126/0x224
[ 16.787021] [<c015d140>] ? do_irqd+0x0/0x224
[ 16.787021] [<c013ae9d>] kthread+0x3b/0x62
[ 16.787021] [<c013ae62>] ? kthread+0x0/0x62
[ 16.787021] [<c0108287>] kernel_thread_helper+0x7/0x10
[ 16.787021] =======================
Sunday, 13 of July 2008 10:26:30 Andrew Morton napisał(a):
> On Sun, 13 Jul 2008 01:27:36 +0200 "Jakub W. Jozwicki" <[email protected]>
wrote:
> > Change locking surrounding kmap_atomic from local_irqsave to
> > local_irqsave_nort. This fixes issues with PREEMPT_RT.
>
> I assume this is a -rt kernel patch.
>
> > --- linux-2.6.25.10/drivers/ata/libata-core.c 2008-07-03
> > 05:46:47.000000000 +0200
> > +++ linux-2.6.25.10-rt7/drivers/ata/libata-core.c 2008-07-12
> > 23:59:33.132140258 +0200
> > @@ -5157,14 +5157,14 @@
> > unsigned long flags;
> >
> > /* FIXME: use a bounce buffer */
> > - local_irq_save(flags);
> > + local_irq_save_nort(flags);
>
> eww. If we're going to have to do stuff like this in mainline then
> there might be a revolt.
Sorry, this was for -rt only.
[ 17.012011] BUG: sleeping function called from invalid context IRQ-14(5732)
at arch/x86/mm/highmem_32.c:8
[ 17.012011] in_atomic():0 [00000000], irqs_disabled():1
[ 17.012011] Pid: 5732, comm: IRQ-14 Not tainted 2.6.25.10-rtXXX #11
[ 17.012011] [<c0120fc4>] __might_sleep+0xf1/0xf8
[ 17.012011] [<c011c035>] kmap+0x47/0x5a
[ 17.012011] [<c033e728>] ata_hsm_move+0x3d7/0x657
[ 17.012011] [<c0342fd6>] ata_interrupt+0x14e/0x1cb
[ 17.012011] [<c015c72c>] handle_IRQ_event+0x4e/0xd1
[ 17.012011] [<c015d266>] do_irqd+0x126/0x224
[ 17.012011] [<c015d140>] ? do_irqd+0x0/0x224
[ 17.012011] [<c013ae9d>] kthread+0x3b/0x62
[ 17.012011] [<c013ae62>] ? kthread+0x0/0x62
[ 17.012011] [<c0108287>] kernel_thread_helper+0x7/0x10
[ 17.012011] =======================
> Sent patch was for:
>
> [ 16.787021] BUG: sleeping function called from invalid context IRQ-14(5730)
> at arch/x86/mm/highmem_32.c:8
Fine - but the right fix is still to apply the patches that use a bounce
buffer, otherwise you might paper over the warning but you'll trash rt
performance. It needs fixing anyway especially with Tejun's changes to
the ATAPI logic to use PIO more often
Alan
Jakub W. Jozwicki wrote:
>
> Sorry, this was for -rt only.
>
> [ 17.012011] BUG: sleeping function called from invalid context IRQ-14(5732)
> at arch/x86/mm/highmem_32.c:8
> [ 17.012011] in_atomic():0 [00000000], irqs_disabled():1
> [ 17.012011] Pid: 5732, comm: IRQ-14 Not tainted 2.6.25.10-rtXXX #11
> [ 17.012011] [<c0120fc4>] __might_sleep+0xf1/0xf8
> [ 17.012011] [<c011c035>] kmap+0x47/0x5a
>
The subject says kmap_atomic, but this is kmap. It definitely makes no
sense to call kmap in an IRQ, regardless of the locking. There seems to
be a larger structural problem here.
> [ 17.012011] [<c033e728>] ata_hsm_move+0x3d7/0x657
> [ 17.012011] [<c0342fd6>] ata_interrupt+0x14e/0x1cb
> [ 17.012011] [<c015c72c>] handle_IRQ_event+0x4e/0xd1
> [ 17.012011] [<c015d266>] do_irqd+0x126/0x224
> [ 17.012011] [<c015d140>] ? do_irqd+0x0/0x224
> [ 17.012011] [<c013ae9d>] kthread+0x3b/0x62
> [ 17.012011] [<c013ae62>] ? kthread+0x0/0x62
> [ 17.012011] [<c0108287>] kernel_thread_helper+0x7/0x10
> [ 17.012011] =======================
>
J
Sunday, 13 of July 2008 19:46:29 Jeremy Fitzhardinge napisał(a):
> Jakub W. Jozwicki wrote:
> > Sorry, this was for -rt only.
> >
> > [ 17.012011] BUG: sleeping function called from invalid context
> > IRQ-14(5732) at arch/x86/mm/highmem_32.c:8
> > [ 17.012011] in_atomic():0 [00000000], irqs_disabled():1
> > [ 17.012011] Pid: 5732, comm: IRQ-14 Not tainted 2.6.25.10-rtXXX #11
> > [ 17.012011] [<c0120fc4>] __might_sleep+0xf1/0xf8
> > [ 17.012011] [<c011c035>] kmap+0x47/0x5a
>
> The subject says kmap_atomic, but this is kmap. It definitely makes no
> sense to call kmap in an IRQ, regardless of the locking. There seems to
> be a larger structural problem here.
>
--- linux-2.6.25.8-rt7.orig/include/asm-x86/highmem.h 2008-06-23
19:12:47.000000000 -0400
+++ linux-2.6.25.8-rt7/include/asm-x86/highmem.h 2008-06-23
19:13:58.000000000 -0400
+/*
+ * on PREEMPT_RT kmap_atomic() is a wrapper that uses kmap():
+ */
+#ifdef CONFIG_PREEMPT_RT
+# define kmap_atomic_prot(page, type, prot) ({ pagefault_disable();
kmap(page); })
+# define kmap_atomic(page, type) ({ pagefault_disable(); kmap(page); })
+# define kmap_atomic_pfn(pfn, type) kmap(pfn_to_page(pfn))
+# define kunmap_atomic(kvaddr, type) do { pagefault_enable();
kunmap_virt(kvaddr); } while(0)
+# define kmap_atomic_to_page(kvaddr) kmap_to_page(kvaddr)
+#else
+# define kmap_atomic_prot(page, type, prot) __kmap_atomic_prot(page, type,
prot)
+# define kmap_atomic(page, type) __kmap_atomic(page, type)
+# define kmap_atomic_pfn(pfn, type) __kmap_atomic_pfn(pfn, type)
+# define kunmap_atomic(kvaddr, type) __kunmap_atomic(kvaddr, type)
+# define kmap_atomic_to_page(kvaddr) __kmap_atomic_to_page(kvaddr)
+#endif
+
Jakub W. Jozwicki wrote:
> Sunday, 13 of July 2008 19:46:29 Jeremy Fitzhardinge napisał(a):
>
>> Jakub W. Jozwicki wrote:
>>
>>> Sorry, this was for -rt only.
>>>
>>> [ 17.012011] BUG: sleeping function called from invalid context
>>> IRQ-14(5732) at arch/x86/mm/highmem_32.c:8
>>> [ 17.012011] in_atomic():0 [00000000], irqs_disabled():1
>>> [ 17.012011] Pid: 5732, comm: IRQ-14 Not tainted 2.6.25.10-rtXXX #11
>>> [ 17.012011] [<c0120fc4>] __might_sleep+0xf1/0xf8
>>> [ 17.012011] [<c011c035>] kmap+0x47/0x5a
>>>
>> The subject says kmap_atomic, but this is kmap. It definitely makes no
>> sense to call kmap in an IRQ, regardless of the locking. There seems to
>> be a larger structural problem here.
>>
>>
>
> --- linux-2.6.25.8-rt7.orig/include/asm-x86/highmem.h 2008-06-23
> 19:12:47.000000000 -0400
> +++ linux-2.6.25.8-rt7/include/asm-x86/highmem.h 2008-06-23
> 19:13:58.000000000 -0400
>
>
> +/*
> + * on PREEMPT_RT kmap_atomic() is a wrapper that uses kmap():
>
OK, I guess the "structural problem" is RT ;)
J