2008/7/27 Adel Gadllah <adel.gadllah@xxxxxxxxx>: > 2008/7/26 FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>: >> cmd_filter works only for the block layer SG_IO with SCSI block >> devices. It breaks scsi/sg.c, bsg, and the block layer SG_IO with SCSI >> character devices (such as st). We might hit a kernel crash with them. >> >> The problem is that cmd_filter code accesses to gendisk (having struct >> blk_scsi_cmd_filter) via inode->i_bdev->bd_disk. It works for only >> SCSI block device files. With character device files, inode->i_bdev >> leads you to struct cdev. inode->i_bdev->bd_disk->blk_scsi_cmd_filter >> isn't safe. For example, I got the following kernel crash with bsg: >> >> Pid: 1480, comm: bsg-test Not tainted (2.6.26-06879-gfb2e405 #1) >> EIP: 0060:[<c01b02fd>] EFLAGS: 00010202 CPU: 0 >> EIP is at blk_cmd_filter_verify_command+0x1e/0x41 >> EAX: 00000000 EBX: 00000237 ECX: 00000011 EDX: 00000003 >> ESI: df9692ae EDI: de93485c EBP: de8ea3a8 ESP: de937e90 >> DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 >> Process bsg-test (pid: 1480, ti=de936000 task=df8b7230 task.ti=de936000) >> Stack: de937ec4 df969228 fffffff2 c01b0866 df025030 00000000 de937ec4 c01b1009 >> bf9a5b10 de8ea3a8 c01b110e 00000246 df1985f4 00000051 00000000 00000000 >> 00000006 bf9a5bd2 00000000 00000000 00000000 00000000 00000000 00000000 >> Call Trace: >> [<c01b0866>] bsg_map_hdr+0xe7/0x225 >> [<c01b1009>] bsg_ioctl+0x0/0x17c >> [<c01b110e>] bsg_ioctl+0x105/0x17c >> [<c01b1009>] bsg_ioctl+0x0/0x17c >> [<c015a11a>] vfs_ioctl+0x16/0x48 >> [<c015a332>] do_vfs_ioctl+0x1e6/0x1f9 >> [<c01b770c>] trace_hardirqs_on_thunk+0xc/0x10 >> [<c015a371>] sys_ioctl+0x2c/0x43 >> [<c01028b1>] sysenter_do_call+0x12/0x35 >> ======================= >> Code: 10 89 fa ff d3 89 c2 89 d0 5b 5e 5f c3 57 56 53 89 c3 89 d6 89 cf b8 11 00 00 00 e8 fd 94 f6 ff 85 c0 75 1f 85 db 74 1f 0f b6 16 <0f> a3 13 19 c0 85 c0 75 0f 0f a3 53 20 19 c0 85 c0 74 09 f6 07 >> EIP: [<c01b02fd>] blk_cmd_filter_verify_command+0x1e/0x41 SS:ESP 0068:de937e90 >> ---[ end trace 0cceddb2f202a402 ]--- >> >> >> SCSI ULDs don't expose gendisk; they keep it private. bsg needs to be >> independent on any protocols. We shouldn't change ULDs to expose their >> gendisk. >> >> This patchset moves struct blk_scsi_cmd_filter from gendisk to >> request_queue, a common object, which eveyone can access to. >> >> The user interface doesn't change; users can change the filters via >> /sys/block/. gendisk has a pointer to request_queue so the cmd_filter >> code accesses to struct blk_scsi_cmd_filter. > > Thanks for the fixes, wanted to test them but they don't apply cleanly > here (tried against Jens and Linus tree). > Anyway the look fine to me from just reading it ... have you tested if > changing the filter actually works? > Should be "Anyway the look fine to me from just reading them ... have you tested if changing the filter (via sysfs) actually works?" -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
