Re: 2.6.20-rc6-mm1

From: Jiri Slaby
Date: Tue Jan 30 2007 - 15:10:36 EST


Andrew Morton napsal(a):
On Mon, 29 Jan 2007 23:27:27 -0800
Andrew Morton <akpm@xxxxxxxx> wrote:

On Sun, 28 Jan 2007 11:25:42 +0100
Jiri Slaby <jirislaby@xxxxxxxxx> wrote:

Andrew Morton napsal(a):
Temporarily at

http://userweb.kernel.org/~akpm/2.6.20-rc6-mm1/
I'm still seeing this during bootup:
BUG: at /home/l/latest/xxx/arch/i386/mm/highmem.c:52 kmap_atomic()
[<c0104ffb>] show_trace_log_lvl+0x1a/0x30
[<c01056b5>] show_trace+0x12/0x14
[<c010573c>] dump_stack+0x16/0x18
[<c011b24f>] kmap_atomic+0x16c/0x20e
[<c01b279e>] ntfs_end_buffer_async_read+0x18e/0x2ed
[<c0183352>] end_bio_bh_io_sync+0x26/0x3f
[<c0184dd4>] bio_endio+0x37/0x62
[<c01cda43>] __end_that_request_first+0x224/0x444
[<c01cdc6b>] end_that_request_chunk+0x8/0xa
[<c024507d>] scsi_end_request+0x1f/0xc7
[<c02451e6>] scsi_io_completion+0x7b/0x33a
[<c024aa5d>] sd_rw_intr+0x23/0x1ab
[<c02415ed>] scsi_finish_command+0x42/0x47
[<c0245a38>] scsi_softirq_done+0x64/0xcf
[<c01cf9e6>] blk_done_softirq+0x54/0x62
[<c0127bc5>] __do_softirq+0x75/0xde
[<c0127c69>] do_softirq+0x3b/0x3d
[<c0127ee6>] irq_exit+0x3b/0x3d
[<c0106804>] do_IRQ+0x51/0x8d
[<c0104a5f>] common_interrupt+0x23/0x28
[<c010241a>] cpu_idle+0x80/0xc3
[<c010140d>] rest_init+0x23/0x36
[<c045ea59>] start_kernel+0x3a5/0x43c
[<00000000>] 0x0
=======================

I.e. KM_BIO_SRC_IRQ through softirq path.
[...]
Actually, this isn't related to softirq-vs-hardirq. Most interrupt

I meant that hardirq path was fixed (by adding KM_BIO_SRC_IRQ to kmap_atomic
"type !=" test in arch/i386/mm/highmem.c) and softirq was not yet.

handlers are interruptible, so the rule is simply that KM_BIO_SRC_IRQ must
always be taken under local_irq_disable().

A quick scan indicates that the following files might be buggy in this
regard:

drivers/mmc/wbsd.c
drivers/mmc/at91_mci.c
drivers/mmc/sdhci.c
drivers/scsi/scsi_lib.c when called from stex.c
fs/ntfs/aops.c

Happily, KM_BIO_DST_IRQ has no users and can presumably be removed.


Fixes for stex and ntfs follow.

Clean boot now.

thanks,
--
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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