Re: [Announce] 2.6.29-rc4-rt2

Thomas Meyer
2009-02-20T16:10:09Z

Am Freitag, den 20.02.2009, 08:49 +0100 schrieb Peter Zijlstra:
> On Fri, 2009-02-20 at 07:32 +0100, Thomas Meyer wrote:
> > Are you interested in these BUG reports?
>
> Yes we are, thanks!
>
> > Without CONFIG_HIGHPTE kernel boots and seems to work correct, but I'm
> > hitting these two BUGs:
>
> They appear to be identical, so I'll consider them two instances of one
> bug :-)
>
> > [ 19.840100] BUG: sleeping function called from invalid context at arch/x86/mm/highmem_32.c:8
> > [ 19.840105] in_atomic(): 0, irqs_disabled(): 1, pid: 718, name: IRQ-14
> > [ 19.840110] Pid: 718, comm: IRQ-14 Tainted: G W 2.6.29-rc4-rt2-tip #55
> > [ 19.840113] Call Trace:
> > [ 19.840123] [<c0444cbd>] __might_sleep+0xda/0xf0
> > [ 19.840128] [<c043ee31>] kmap+0x50/0x77
> > [ 19.840133] [<c0663e35>] sg_miter_next+0xc1/0xdf
> > [ 19.840137] [<c0663ee8>] sg_copy_buffer+0x95/0xc5
> > [ 19.840141] [<c0663f35>] sg_copy_to_buffer+0x1d/0x33
> > [ 19.840149] [<c0774ab1>] atapi_qc_complete+0x25a/0x2c5
> > [ 19.840153] [<c076dece>] __ata_qc_complete+0xb4/0xcd
> > [ 19.840157] [<c076f844>] ata_qc_complete+0x1be/0x1d7
> > [ 19.840162] [<c077c812>] ata_hsm_qc_complete+0xa9/0xd3
> > [ 19.840166] [<c077ceb7>] ata_sff_hsm_move+0x67b/0x6da
> > [ 19.840171] [<c077d19b>] ata_sff_interrupt+0x15d/0x205
> > [ 19.840176] [<c049440a>] handle_IRQ_event+0x4b/0xce
> > [ 19.840180] [<c0494ac7>] do_irqd+0x141/0x271
> > [ 19.840184] [<c0494986>] ? do_irqd+0x0/0x271
> > [ 19.840189] [<c0467022>] kthread+0x4a/0x82
> > [ 19.840192] [<c0466fd8>] ? kthread+0x0/0x82
> > [ 19.840197] [<c0420b67>] kernel_thread_helper+0x7/0x10
>
> sg_copy_buffer() seems to disable IRQs, however since on -rt everything
> is a irq-thread and kmap is preemptible, we don't appear to have that
> need.
>
> CC'd everybody who ever touched the file.
>
> ---
> lib/scatterlist.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/scatterlist.c b/lib/scatterlist.c
> index b7b449d..4c6510d 100644
> --- a/lib/scatterlist.c
> +++ b/lib/scatterlist.c
> @@ -426,7 +426,7 @@ static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
>
> sg_miter_start(&miter, sgl, nents, SG_MITER_ATOMIC);
>
> - local_irq_save(flags);
> + local_irq_save_nort(flags);
>
> while (sg_miter_next(&miter) && offset < buflen) {
> unsigned int len;
> @@ -445,7 +445,7 @@ static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
>
> sg_miter_stop(&miter);
>
> - local_irq_restore(flags);
> + local_irq_restore_nort(flags);
> return offset;
> }
>

With above patch I get a lot of warnings in

lib/scatterlist.c:395 sg_miter_stop+0x5a/0xa4().

Like:
[ 34.946650] ------------[ cut here ]------------
[ 34.946653] WARNING: at lib/scatterlist.c:395 sg_miter_stop+0x5a/0xa4()
[ 34.946655] Hardware name: MacBookPro1,1
[ 34.946657] Modules linked in: ath5k mac80211 cfg80211 video [last unloaded: scsi_wait_scan]
[ 34.946665] Pid: 8, comm: sirq-block/0 Tainted: G W 2.6.29-rc4-rt2-tip #56
[ 34.946690] Call Trace:
[ 34.946694] [<c0451e50>] warn_slowpath+0x8a/0xd3
[ 34.946698] [<c09ab0e4>] ? __spin_unlock+0x1e/0x43
[ 34.946703] [<c04476d6>] ? enqueue_task_fair+0x2df/0x331
[ 34.946707] [<c0442c7c>] ? enqueue_task+0x70/0x8e
[ 34.946711] [<c044cf91>] ? try_to_wake_up+0x2eb/0x306
[ 34.946715] [<c0663e0a>] sg_miter_stop+0x5a/0xa4
[ 34.946719] [<c0663fd6>] sg_copy_buffer+0xa3/0xbe
[ 34.946723] [<c0664041>] sg_copy_from_buffer+0x1d/0x33
[ 34.946728] [<c0774c3d>] ata_scsi_rbuf_fill+0x59/0x90
[ 34.946731] [<c07760ed>] ? ata_scsiop_inq_80+0x0/0x41
[ 34.946735] [<c0755b3e>] ? scsi_done+0x0/0x2d
[ 34.946739] [<c0755b3e>] ? scsi_done+0x0/0x2d
[ 34.946743] [<c0774e24>] ata_scsi_simulate+0x1b0/0x1f8
[ 34.946747] [<c0755b3e>] ? scsi_done+0x0/0x2d
[ 34.946752] [<c0775178>] ata_scsi_queuecmd+0x16d/0x1bc
[ 34.946756] [<c0755de0>] scsi_dispatch_cmd+0x18a/0x208
[ 34.946760] [<c075b378>] scsi_request_fn+0x349/0x487
[ 34.946764] [<c064bcb6>] blk_invoke_request_fn+0x75/0x146
[ 34.946768] [<c064c671>] __blk_run_queue+0x2d/0x42
[ 34.946772] [<c064c6ac>] blk_run_queue+0x26/0x46
[ 34.946775] [<c075a836>] scsi_run_queue+0x283/0x321
[ 34.946780] [<c075b6c9>] scsi_next_command+0x36/0x54
[ 34.946783] [<c075b8e2>] scsi_end_request+0x84/0xa1
[ 34.946787] [<c075beb9>] scsi_io_completion+0x1a4/0x3a6
[ 34.946792] [<c075c1be>] ? scsi_device_unbusy+0x8c/0xa3
[ 34.946796] [<c0755b25>] scsi_finish_command+0xd3/0xec
[ 34.946800] [<c075c3bc>] scsi_softirq_done+0x104/0x11d
[ 34.946804] [<c06505df>] blk_done_softirq+0x5f/0x7e
[ 34.946808] [<c04575e3>] ksoftirqd+0x12d/0x223
[ 34.946813] [<c04574b6>] ? ksoftirqd+0x0/0x223
[ 34.946816] [<c0467022>] kthread+0x4a/0x82
[ 34.946820] [<c0466fd8>] ? kthread+0x0/0x82
[ 34.946824] [<c0420b67>] kernel_thread_helper+0x7/0x10
[ 34.946827] ---[ end trace a7919e7f17c0a754 ]---