2013/3/8 Greg KH <[email protected]>: > On Fri, Mar 08, 2013 at 09:35:17PM +0200, Tommi Rantala wrote: >> [ 205.043027] kernel BUG at >> /home/ttrantal/git/linux-2.6/fs/sysfs/group.c:65! > > And now we crash. For a loop device we are trying to add. > > Ick. > > I'm guessing that the caller of whom ever tried to create the duplicate > sysfs device, didn't check the return value, and then tried to add a > sysfs group to that object. > > So we crashed, as I'm betting sysfs_create_group() was called with a > NULL kobject. > > I think that BUG() for such a stupid thing is flat out wrong, we should > be returning an error instead, so I'll go fix that. If you change the > line that this BUG() call is, from: > BUG_ON(!kobj || (!update && !kobj->sd)); > to > BUG_ON(!update && !kobj->sd); > > does it still crash?
Yes: [ 31.419720] kernel BUG at /home/ttrantal/git/linux-2.6/fs/sysfs/group.c:65! [ 31.419746] invalid opcode: 0000 [#1] SMP [ 31.419746] CPU 0 [ 31.419746] Pid: 3396, comm: trinity-child0 Tainted: G W 3.9.0-rc1+ #104 Bochs Bochs [ 31.419746] RIP: 0010:[<ffffffff81224886>] [<ffffffff81224886>] internal_create_group+0x26/0x220 [ 31.419746] RSP: 0018:ffff88007935fd08 EFLAGS: 00010246 [ 31.419746] RAX: ffff880077264520 RBX: ffff8800792ea800 RCX: 0000000000000006 [ 31.419746] RDX: ffffffff82849980 RSI: 0000000000000000 RDI: ffff8800792ea880 [ 31.419746] RBP: ffff88007935fd58 R08: 0000000000000070 R09: 0000000000000001 [ 31.419746] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88007a92bae8 [ 31.419746] R13: ffffffff82849980 R14: 0000000000000000 R15: ffff8800792ea870 [ 31.419746] FS: 00007f2d1ba2c700(0000) GS:ffff88007f800000(0000) knlGS:0000000000000000 [ 31.419746] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 31.419746] CR2: 00007f10bef71350 CR3: 0000000079351000 CR4: 00000000000006f0 [ 31.419746] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 31.419746] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 31.419746] Process trinity-child0 (pid: 3396, threadinfo ffff88007935e000, task ffff880077264520) [ 31.419746] Stack: [ 31.419746] ffff88007935fd28 ffff8800792ea880 ffff88007a92c230 ffff88007a92bae8 [ 31.419746] ffff88007935fd38 ffff8800792ea800 ffff88007a92bae8 ffff8800792ea800 [ 31.419746] ffff8800792ea870 ffff8800792ea870 ffff88007935fd68 ffffffff81224a8e [ 31.419746] Call Trace: [ 31.419746] [<ffffffff81224a8e>] sysfs_create_group+0xe/0x10 [ 31.419746] [<ffffffff8113f2a4>] blk_trace_init_sysfs+0x14/0x20 [ 31.419746] [<ffffffff81345320>] blk_register_queue+0x100/0x130 [ 31.419746] [<ffffffff8134ca68>] add_disk+0x358/0x4b0 [ 31.419746] [<ffffffff814f7a27>] loop_add+0x1d7/0x220 [ 31.419746] [<ffffffff814f9295>] loop_control_ioctl+0x65/0x170 [ 31.419746] [<ffffffff811b9542>] do_vfs_ioctl+0x522/0x570 [ 31.419746] [<ffffffff8130a4b3>] ? file_has_perm+0x83/0xa0 [ 31.419746] [<ffffffff811b95ed>] sys_ioctl+0x5d/0xa0 [ 31.419746] [<ffffffff813663fe>] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 31.419746] [<ffffffff81faed69>] system_call_fastpath+0x16/0x1b [ 31.419746] Code: 00 00 00 66 90 55 48 89 e5 41 57 41 56 41 89 f6 41 55 49 89 d5 41 54 53 48 83 ec 28 85 f6 48 89 7d b8 75 11 48 83 7f 30 00 75 19 <0f> 0b 0f 1f 84 00 00 00 00 00 48 8b 45 b8 48 83 78 30 00 0f 84 [ 31.419746] RIP [<ffffffff81224886>] internal_create_group+0x26/0x220 [ 31.419746] RSP <ffff88007935fd08> [ 31.471213] ---[ end trace f722dfd576c9fd94 ]--- > I'd rather just warn there anyway, sysfs shouldn't be calling BUG on > anything, it should always be able to recover and just return errors. > > thanks, > > greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
