]> err.no Git - linux-2.6/commit
ide: fix regression caused by ide_device_{get,put}() addition (take 2)
authorBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Tue, 5 Aug 2008 16:16:59 +0000 (18:16 +0200)
committerBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Tue, 5 Aug 2008 16:16:59 +0000 (18:16 +0200)
commitd3e33ff59facec005e48ba3360502b73a04e4b4e
tree7f5b6354d5d6794b35a5ea2bcee33ea16d8e326c
parentb5b9309d3415480b3e66314a1d6c89db58bff9de
ide: fix regression caused by ide_device_{get,put}() addition (take 2)

On Monday 28 July 2008, Benjamin Herrenschmidt wrote:

[...]

> Vector: 300 (Data Access) at [c58b7b80]
>     pc: c014f264: elv_may_queue+0x10/0x44
>     lr: c0152750: get_request+0x2c/0x2c0
>     sp: c58b7c30
>    msr: 1032
>    dar: c
>  dsisr: 40000000
>   current = 0xc58aaae0
>     pid   = 854, comm = media-bay
> enter ? for help
> mon> t
> [c58b7c40c0152750 get_request+0x2c/0x2c0
> [c58b7c70c0152a08 get_request_wait+0x24/0xec
> [c58b7cc0c0225674 ide_cd_queue_pc+0x58/0x1a0
> [c58b7d40c022672c ide_cdrom_packet+0x9c/0xdc
> [c58b7d70c0261810 cdrom_get_disc_info+0x60/0xd0
> [c58b7dc0c026208c cdrom_mrw_exit+0x1c/0x11c
> [c58b7e30c0260f7c unregister_cdrom+0x84/0xe8
> [c58b7e50c022395c ide_cd_release+0x80/0x84
> [c58b7e70c0163650 kref_put+0x54/0x6c
> [c58b7e80c0223884 ide_cd_put+0x40/0x5c
> [c58b7ea0c0211100 generic_ide_remove+0x28/0x3c
> [c58b7eb0c01e9d34 __device_release_driver+0x78/0xb4
> [c58b7ec0c01e9e44 device_release_driver+0x28/0x44
> [c58b7ee0c01e8f7c bus_remove_device+0xac/0xd8
> [c58b7f00c01e7424 device_del+0x104/0x198
> [c58b7f20c01e74d0 device_unregister+0x18/0x30
> [c58b7f40c02121c4 __ide_port_unregister_devices+0x6c/0x88
> [c58b7f60c0212398 ide_port_unregister_devices+0x38/0x80
> [c58b7f80c0208ca4 media_bay_step+0x1cc/0x5c0
> [c58b7fb0c0209124 media_bay_task+0x8c/0xcc
> [c58b7fd0c00485c0 kthread+0x48/0x84
> [c58b7ff0c0011b20 kernel_thread+0x44/0x60

The guilty commit turned out to be 08da591e14cf87247ec09b17c350235157a92fc3
("ide: add ide_device_{get,put}() helpers").  ide_device_put() is called
before kref_put() in ide_cd_put() so IDE device is already gone by the time
ide_cd_release() is reached.

Fix it by calling ide_device_get() before kref_get() and ide_device_put()
after kref_put() in all affected device drivers.

v2:
Brown paper bag time.  In v1 cd->drive was referenced after dropping last
reference on cd object (which could result in OOPS in ide_device_put() as
reported/debugged by Mariusz Kozlowski).  Fix it by caching cd->drive in
the local variable (fix other device drivers too).

Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reported-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Borislav Petkov <petkovbb@gmail.com>
Tested-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
drivers/ide/ide-cd.c
drivers/ide/ide-disk.c
drivers/ide/ide-floppy.c
drivers/ide/ide-tape.c
drivers/scsi/ide-scsi.c