Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 23 Oct 2003 12:48:46 +1000 | From | Nick Piggin <> | Subject | Re: Elevator bug in concert with usb-storage |
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Fredrik Tolf wrote:
>Hello, > >I believe that there is a bug in the usb-storage code. I'm using >2.6.0-test8-mm1, but I have experienced this in essentially all >2.6.0-test* kernels. Mostly anytime when I remove a usb-storage device >(especially before umounting it), I get a SEGV followed by general >unstability in the SCSI subsys. > >After doing some research, I believe it is because the I/O scheduler >is released before the SCSI subsys stops using it. Here is the SEGV >report: > >Unable to handle kernel NULL pointer dereference at virtual address 00000001 > printing eip: >00000001 >*pde = 00000000 >Oops: 0000 [#1] >PREEMPT >CPU: 0 >EIP: 0060:[<00000001>] Not tainted VLI >EFLAGS: 00010202 >EIP is at 0x1 >eax: d8b83180 ebx: dafc4e00 ecx: 00000000 edx: dafc4e00 >esi: dafc4e10 edi: c03465e0 ebp: d990fe64 esp: d990fe58 >ds: 007b es: 007b ss: 0068 >Process umount (pid: 1744, threadinfo=d990e000 task=d8ba4080) >Stack: c02173d7 dafc4e00 d8b83180 d990fe78 c0218f5d dafc4e00 df774800 c03465b0 > d990fe8c e0952fb5 dafc4e00 db8e3ca0 c03465b0 d990fe9c e0953f83 df774800 > 00000000 d990feac c021480a df774980 df7749a8 d990fec4 c01c26e3 df7749a8 >Call Trace: > [<c02173d7>] elevator_exit+0x2d/0x3c > [<c0218f5d>] blk_cleanup_queue+0x65/0x70 > [<e0952fb5>] scsi_free_sdev+0x11f/0x15a [scsi_mod] > [<e0953f83>] scsi_device_dev_release+0x15/0x22 [scsi_mod] > [<c021480a>] device_release+0x1a/0x60 > [<c01c26e3>] kobject_cleanup+0x63/0x70 > [<e094eb1c>] scsi_device_put+0x68/0xa6 [scsi_mod] > [<e08a94cb>] sd_release+0x27/0x46 [sd_mod] > [<c01569c5>] blkdev_put+0x1a7/0x1bc > [<c015698f>] blkdev_put+0x171/0x1bc > [<c015566b>] kill_block_super+0x25/0x2c > [<c01548c7>] deactivate_super+0x67/0xae > [<c01686c2>] sys_umount+0x36/0x84 > [<c014e9c5>] filp_close+0x43/0x66 > [<c016871d>] sys_oldumount+0xd/0x10 > [<c02bafeb>] syscall_call+0x7/0xb > >Code: Bad EIP value. > >It seems as if the elevator_exit_fn is set to 1, and there is a >message logged just before the SEGV report spits out that an I/O >scheduler is released, which makes me draw the conclusion that the >kernel tries to free the I/O scheduler twice. > >My apologies for taking up your time if this is a known a fixed >problem. However, if it is, can you point me to some information on >how to remedy it? >
James is having a look at refounting issues now. So it will be fixed.
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