Re: initcall calibrate_xor_blocks returned with preemption imbalance

From: Boaz Harrosh
Date: Thu Oct 10 2013 - 16:41:47 EST


On 10/10/2013 02:02 AM, Fengguang Wu wrote:
> Greetings,
>
> I got the below dmesg and the first bad commit is
>

Dear Wu

This 20545536cd8ea949c61527b6395ec8c0d2c237b1 is from my tree at linux-open-osd.org
How did you happen to find it and run with it at all?

I have never pushed it to any mailing list or blessed it for release.
Yes it has a known problem that I never bothered to fix. I carry
it in my own development trees so I can run xor.ko on UML.

If it has leaked to any upstream trees, I'm so sorry tell me where
you found it and I'll have it removed.

I can see below:
Merge 'open-osd/exofs_ioctl' into devel-hourly-2013101007

What is devel-hourly and what does exofs_ioctl branch useful for.
exofs_ioctl is for NFS-Ganesha pnfs support. It is not good for
any other purpose.
If you are developing NFS-Ganesha pnfs code feel free to remove
this patch, again it is so I can run exofs on UML which uses
xor.ko. If you use VMs or HW you do not have this problem.

Thanks
Boaz

> commit 20545536cd8ea949c61527b6395ec8c0d2c237b1
> Author: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
> Date: Thu Jul 19 15:22:37 2012 +0300
>
> RFC: do_xor_speed Broken on UML do to jiffies
>
> Remember that hang I reported a while back on UML. Well
> I'm at it again, and it still hangs and I found why.
>
> I have dprinted jiffies and it never advances during the
> loop at do_xor_speed. There for it is stuck in an endless
> loop. I have also dprinted current_kernel_time() and it
> returns the same constant value as well.
>
> Note that it does usually work on UML, only during
> the modprobe of xor.ko while that test is running. It looks
> like some lucking is preventing the clock from ticking.
>
> However ktime_get_ts does work for me so I changed the code
> as below, so I can work. See how I put several safety
> guards, to never get hangs again.
> And I think my time based approach is more accurate then
> previous system.
>
> UML guys please investigate the jiffies issue? what is
> xor.ko not doing right?
>
> Signed-off-by: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
>
> [ 0.232004] generic_sse: 6816.333 MB/sec
> [ 0.233534] xor: using function: prefetch64-sse (9178.666 MB/sec)
> [ 0.235445] ------------[ cut here ]------------
> [ 0.236010] WARNING: CPU: 0 PID: 1 at init/main.c:701 do_one_initcall+0x128/0x138()
> [ 0.240041] initcall calibrate_xor_blocks+0x0/0x144 returned with preemption imbalance
> [ 0.242872] Modules linked in:
> [ 0.244006] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.12.0-rc4-wl-02197-g3d5587e #119
> [ 0.246837] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
> [ 0.248004] 0000000000000000 ffff88000e1e5e00 ffffffff81a3a6bf ffff88000e1e5e48
> [ 0.252003] ffff88000e1e5e38 ffffffff810c53d5 ffffffff81000315 ffffffff8256ff16
> [ 0.255243] 0000000000000000 0000000000000000 ffff88000e1e5fd8 ffff88000e1e5e98
> [ 0.258537] Call Trace:
> [ 0.260010] [<ffffffff81a3a6bf>] dump_stack+0x54/0x74
> [ 0.261730] [<ffffffff810c53d5>] warn_slowpath_common+0x7f/0x98
> [ 0.263623] [<ffffffff81000315>] ? do_one_initcall+0x128/0x138
> [ 0.264006] [<ffffffff8256ff16>] ? do_xor_speed+0xe2/0xe2
> [ 0.265785] [<ffffffff810c543a>] warn_slowpath_fmt+0x4c/0x4e
> [ 0.268007] [<ffffffff811767d9>] ? free_pages+0x45/0x47
> [ 0.269751] [<ffffffff8256ff16>] ? do_xor_speed+0xe2/0xe2
> [ 0.272006] [<ffffffff81000315>] do_one_initcall+0x128/0x138
> [ 0.273843] [<ffffffff82532ed3>] kernel_init_freeable+0x159/0x1da
> [ 0.276005] [<ffffffff8253274d>] ? do_early_param+0x88/0x88
> [ 0.277835] [<ffffffff81a2a057>] ? rest_init+0xdb/0xdb
> [ 0.280006] [<ffffffff81a2a065>] kernel_init+0xe/0xdb
> [ 0.281718] [<ffffffff81a4d97c>] ret_from_fork+0x7c/0xb0
> [ 0.283485] [<ffffffff81a2a057>] ? rest_init+0xdb/0xdb
> [ 0.284021] ---[ end trace 3592511960ba24aa ]---
> [ 0.285636] atomic64 test passed for x86-64 platform with CX8 and with SSE
>
> git bisect start 3d5587ec7222eebd6d2fa2d4b245ef837a8f36fa 15c03dd4859ab16f9212238f29dd315654aa94f6 --
> git bisect good bd1bc39506ad6ce236bf932757d6e3a81b3e3d55 # 09:41 20+ 0 Merge 'regmap/topic/core' into devel-hourly-2013101007
> git bisect good f0a6d5852cc8b4e9e518c0426580f0589327e438 # 10:56 20+ 0 Merge 'arm-soc/next/dt' into devel-hourly-2013101007
> git bisect good 909dc6fa1f1f42dcdae62b07c4d6b894a392e0d7 # 11:36 20+ 0 Merge 'ipsec-next/testing' into devel-hourly-2013101007
> git bisect good 7fb1b0615235b3975def59fbffd0f52c71736bd3 # 11:57 20+ 1 Merge 'arm-soc/next/drivers' into devel-hourly-2013101007
> git bisect good ac5fb9846698e9dffc430ab38c1aaefe50a51980 # 12:22 20+ 0 Merge remote-tracking branch 'regulator/topic/optional' into regulator-next
> git bisect good b9729e9f8d82724c98f13dd358c7b08a4d7de3d2 # 13:31 20+ 3 mtd: nand: pxa3xx_nand: Remove redundant of_match_ptr
> git bisect bad c420082bfcc00a908360edd4bb5826ece1c59ae4 # 14:13 0- 20 Merge 'open-osd/exofs_ioctl' into devel-hourly-2013101007
> git bisect good 3f8985b977fbab1bf7ddea03bf311949ebca4afd # 15:03 20+ 0 Merge remote-tracking branch 'regulator/topic/tps6586x' into regulator-next
> git bisect bad 7425910fffb08f541e4d2819c4ae7900894fc504 # 15:41 0- 1 {OUT-OF-TREE-DEBUG}: Remove the cdb_offset check because of osc-osd bug
> git bisect bad 71e6bb4b77c4782642b3cb6b4f9369191e08b934 # 15:48 0- 1 pnfs_osd_xdr_srv (private): Add pnfs-objects server side XDR encoding/decoding
> git bisect bad 20545536cd8ea949c61527b6395ec8c0d2c237b1 # 16:03 0- 16 RFC: do_xor_speed Broken on UML do to jiffies
> git bisect good 4a9a4b3528afce48d3f4b1c07b988040e78112e2 # 16:22 20+ 0 pnfs: Proper delay for NFS4ERR_RECALLCONFLICT in layout_get_done
> git bisect good 4a9a4b3528afce48d3f4b1c07b988040e78112e2 # 16:36 60+ 0 pnfs: Proper delay for NFS4ERR_RECALLCONFLICT in layout_get_done
> git bisect bad 3d5587ec7222eebd6d2fa2d4b245ef837a8f36fa # 16:36 0- 19 Merge 'tip/x86/bsp-hotplug' into devel-hourly-2013101007
> git bisect good 0e7a3ed04f0cd4311096d691888f88569310ee6c # 16:57 63+ 0 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
> git bisect good a0cf1abc25ac197dd97b857c0f6341066a8cb1cf # 16:57 63+ 0 Add linux-next specific files for 20130927
>
> Thanks,
> Fengguang
>


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