2018-02-27 09:28:54

by Adrian Hunter

[permalink] [raw]
Subject: Re: [PATCH V15 06/22] mmc: block: Add blk-mq support

On 26/02/18 23:48, Dmitry Osipenko wrote:
> On 22.02.2018 20:54, Dmitry Osipenko wrote:
>> On 22.02.2018 10:42, Adrian Hunter wrote:
>>> On 21/02/18 22:50, Dmitry Osipenko wrote:
>>>> On 29.11.2017 16:41, Adrian Hunter wrote:
>>>>> Define and use a blk-mq queue. Discards and flushes are processed
>>>>> synchronously, but reads and writes asynchronously. In order to support
>>>>> slow DMA unmapping, DMA unmapping is not done until after the next request
>>>>> is started. That means the request is not completed until then. If there is
>>>>> no next request then the completion is done by queued work.
>>>>
>>>> Hello,
>>>>
>>>> I'm using (running linux-next and doing some upstream development for) some old
>>>> NVIDIA Tegra tablet that has built-in (internal) and external MMC's and with the
>>>> blk-mq being enabled I'm observing a soft lockup. The lockup seems is
>>>> reproducible quite reliably by running fsck on any MMC partition, sometimes
>>>> kernels lockups on boot during probing partitions table (weirdly only when both
>>>> SDHCI's are present, i.e. internal storage enabled in DT and external SD is
>>>> inserted/enabled) and it also lockups pretty quickly in a case of just a general
>>>> use. Reverting mmc/ commits up to 1bec43a3b18 ("Remove option not to use
>>>> blk-mq") and disabling CONFIG_MMC_MQ_DEFAULT makes everything working fine
>>>> again. There is also a third SDHCI populated with built-in WiFi/Bluetooth SDIO
>>>> and I'm observing odd MMC timeouts with the blk-mq enabled, disabling
>>>> CONFIG_MMC_MQ_DEFAULT fixes these timeouts as well.
>>>>
>>>> Any thoughts?
>>>
>>> SDIO (unless it is a combo card) should be unaffected by changes to the
>>> block driver.
>
> I don't know whether it's a combo card or not. Where I can find info about that?
> Is it mentioned in sysfs somewhere? Alternatively you may take a brief look at
> what brcmfmac driver does, maybe it will tell you immediately whether blk-mq
> affects it or not. And if it's not affected, then it could be that there is some
> other issue that is masked by a properly working block driver.

As linus wrote, if you had a combo card it would also show up as a block
device i.e. for mmc2 it would probably be /dev/mmcblk2 if it existed.

>
>>> I don't have any ideas. Adding more NVIDIA people.
>>>>
>>>> WiFi issue
>>>> ========================
>>>>
>>>> [ 38.247006] mmc2: Timeout waiting for hardware interrupt.
>>>> [ 38.247027] brcmfmac: brcmf_escan_timeout: timer expired
>>>> [ 38.247036] mmc2: sdhci: ============ SDHCI REGISTER DUMP ===========
>>>> [ 38.247047] mmc2: sdhci: Sys addr: 0x00000000 | Version: 0x00000001
>>>> [ 38.247055] mmc2: sdhci: Blk size: 0x00007008 | Blk cnt: 0x00000000
>>>> [ 38.247062] mmc2: sdhci: Argument: 0x21000008 | Trn mode: 0x00000013
>>>> [ 38.247070] mmc2: sdhci: Present: 0x01d70000 | Host ctl: 0x00000013
>>>> [ 38.247077] mmc2: sdhci: Power: 0x00000001 | Blk gap: 0x00000000
>>>> [ 38.247084] mmc2: sdhci: Wake-up: 0x00000000 | Clock: 0x00000007
>>>> [ 38.247091] mmc2: sdhci: Timeout: 0x0000000e | Int stat: 0x00000000
>>>> [ 38.247098] mmc2: sdhci: Int enab: 0x02ff000b | Sig enab: 0x02fc000b
>>>> [ 38.247105] mmc2: sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
>>>> [ 38.247112] mmc2: sdhci: Caps: 0x61ff30b0 | Caps_1: 0x00000000
>>>> [ 38.247119] mmc2: sdhci: Cmd: 0x0000353a | Max curr: 0x00000001
>>>> [ 38.247126] mmc2: sdhci: Resp[0]: 0x00001800 | Resp[1]: 0x08002db5
>>>> [ 38.247133] mmc2: sdhci: Resp[2]: 0x16da8000 | Resp[3]: 0x00000400
>>>> [ 38.247139] mmc2: sdhci: Host ctl2: 0x00000000
>>>> [ 38.247146] mmc2: sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x17c47200
>>>> [ 38.247152] mmc2: sdhci: ============================================
>>>> [ 38.247250] brcmfmac: brcmf_sdio_readframes: read 520 bytes from channel 1
>>>> failed: -84
>>>> [ 38.247274] brcmfmac: brcmf_sdio_rxfail: abort command, terminate frame, send NAK
>>>> [ 40.807019] brcmfmac: brcmf_sdio_bus_rxctl: resumed on timeout
>>>> [ 40.807042] brcmfmac: brcmf_notify_escan_complete: Scan abort failed
>>>> [ 48.487007] mmc2: Timeout waiting for hardware interrupt.
>>>> [ 48.487057] mmc2: sdhci: ============ SDHCI REGISTER DUMP ===========
>>>> [ 48.487096] mmc2: sdhci: Sys addr: 0x00000000 | Version: 0x00000001
>>>> [ 48.487128] mmc2: sdhci: Blk size: 0x00007040 | Blk cnt: 0x00000001
>>>> [ 48.487160] mmc2: sdhci: Argument: 0x21000040 | Trn mode: 0x00000013
>>>> [ 48.487191] mmc2: sdhci: Present: 0x01d70000 | Host ctl: 0x00000013
>>>> [ 48.487221] mmc2: sdhci: Power: 0x00000001 | Blk gap: 0x00000000
>>>> [ 48.487251] mmc2: sdhci: Wake-up: 0x00000000 | Clock: 0x00000007
>>>> [ 48.487281] mmc2: sdhci: Timeout: 0x0000000e | Int stat: 0x00000000
>>>> [ 48.487313] mmc2: sdhci: Int enab: 0x02ff000b | Sig enab: 0x02fc000b
>>>> [ 48.487343] mmc2: sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
>>>> [ 48.487374] mmc2: sdhci: Caps: 0x61ff30b0 | Caps_1: 0x00000000
>>>> [ 48.487404] mmc2: sdhci: Cmd: 0x0000353a | Max curr: 0x00000001
>>>> [ 48.487435] mmc2: sdhci: Resp[0]: 0x00001000 | Resp[1]: 0x08002db5
>>>> [ 48.487466] mmc2: sdhci: Resp[2]: 0x16da8000 | Resp[3]: 0x00000400
>>>> [ 48.487493] mmc2: sdhci: Host ctl2: 0x00000000
>>>> [ 48.487525] mmc2: sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x17c47200
>>>> [ 48.487552] mmc2: sdhci: ============================================
>>>> [ 48.487749] brcmfmac: brcmf_sdio_readframes: read 480 bytes from channel 1
>>>> failed: -84
>>>> [ 48.487822] brcmfmac: brcmf_sdio_rxfail: abort command, terminate frame, send NAK
>>>>
>>>>
>>>> Soft lockup issue
>>>> ========================
>>>>
>>>> # fsck -f /dev/disk/by-uuid/6768309f-3545-49d5-9ac7-d5be24d35ef2
>>>> fsck из util-linux 2.30.2
>>>> e2fsck 1.43.9 (8-Feb-2018)
>>>> Проход 1: Проверка inodes, блокs, а также размеров
>>>> Pass 2: Checking каталог structure
>>>> Pass 3: Checking каталог connectivity
>>>> Pass 4: Checking reference counts
>>>> Pass 5: Checking группа summary information
>>>> ....
>>>>
>>>> [ 125.925436] INFO: task kworker/0:3H:263 blocked for more than 60 seconds.
>>>> [ 125.925496] Not tainted
>>>> 4.16.0-rc2-next-20180220-00101-gaefde91c3955-dirty #2041
>>>> [ 125.925530] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
>>>> message.
>>>> [ 125.925562] kworker/0:3H D 0 263 2 0x00000000
>>>> [ 125.925653] Workqueue: kblockd mmc_blk_mq_complete_work
>>>> [ 125.925747] [<c0b991cc>] (__schedule) from [<c0b998f0>] (schedule+0x60/0xcc)
>>>> [ 125.925805] [<c0b998f0>] (schedule) from [<c086c870>]
>>>> (__mmc_claim_host+0xdc/0x24c)
>>>> [ 125.925849] [<c086c870>] (__mmc_claim_host) from [<c08750bc>]
>>>
>>> That claim host should not be there. Here is a fix for that:
>>>
>>> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
>>> index 908e4db03535..62049f95116b 100644
>>> --- a/drivers/mmc/core/mmc_ops.c
>>> +++ b/drivers/mmc/core/mmc_ops.c
>>> @@ -932,9 +932,7 @@ static int mmc_read_bkops_status(struct mmc_card *card)
>>> int err;
>>> u8 *ext_csd;
>>>
>>> - mmc_claim_host(card->host);
>>> err = mmc_get_ext_csd(card, &ext_csd);
>>> - mmc_release_host(card->host);
>>> if (err)
>>> return err;
>>
>> Looks like this patch fixes all the problems. I'll keep testing it for a couple
>> of days and then report back the final result. Thank you very much.
>
> This patch fixes the lockup (and WiFi MMC timeouts), for that:
>
> Tested-by: Dmitry Osipenko <[email protected]>
>
>
> But still something is wrong... I've been getting occasional EXT4 Ooops's, like
> the one below, and __wait_on_bit() is always figuring in the stacktrace. It
> never happened with blk-mq disabled, though it could be a coincidence and
> actually unrelated to blk-mq patches.

I can't think how an IO driver could cause that.

cc'ing ext4 mailing list for more advice.

>
>
> [ 6625.992337] Unable to handle kernel NULL pointer dereference at virtual
> address 0000001c
> [ 6625.993004] pgd = 00b30c03
> [ 6625.993257] [0000001c] *pgd=00000000
> [ 6625.993594] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
> [ 6625.994022] Modules linked in:
> [ 6625.994326] CPU: 1 PID: 19355 Comm: dpkg Not tainted
> 4.16.0-rc2-next-20180220-00095-ge9c9f5689a84-dirty #2090
> [ 6625.995078] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
> [ 6625.995595] PC is at dx_probe+0x68/0x684
> [ 6625.995947] LR is at __wait_on_bit+0xac/0xc8
> [ 6625.996307] pc : [<c033b960>] lr : [<c0bfbfd4>] psr: 800f0013
> [ 6625.996806] sp : d55e3df0 ip : c0170e88 fp : d55e3e44
> [ 6625.997227] r10: d55e3f4c r9 : d55e3e70 r8 : 00000000
> [ 6625.997650] r7 : c4e13240 r6 : 00000000 r5 : d657db18 r4 : d55e3e8c
> [ 6625.998165] r3 : 0000007b r2 : d5830800 r1 : d5831000 r0 : c4e13240
> [ 6625.998686] Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
> [ 6625.999246] Control: 10c5387d Table: 0a63004a DAC: 00000051
> [ 6625.999710] Process dpkg (pid: 19355, stack limit = 0x139a48b6)
> [ 6626.000184] Stack: (0xd55e3df0 to 0xd55e4000)
> [ 6626.000560] 3de0: 000002e9 d55e3e00
> c0c01964 c0278c70
> [ 6626.001209] 3e00: d55e3e24 014000c0 c04f3580 c0c01958 d55e3e90 801a001a
> d55e3e3c 00000012
> [ 6626.001854] 3e20: d5830800 00000000 d657db18 c24b0000 d55e3e70 d55e3f4c
> d55e3edc d55e3e48
> [ 6626.002502] 3e40: c033d568 c033b904 00000000 600f0013 c029e640 d6cf3540
> ffffe000 00000000
> [ 6626.003150] 3e60: 00076e99 d55e3ef4 d55e3e8c d5830800 d409c440 d409c454
> 00000012 c029e640
> [ 6626.003795] 3e80: d55e3ec4 d55e3e90 c02797b4 c4e13240 00000000 00000000
> 00000000 00000000
> [ 6626.004442] 3ea0: 00000000 00000000 00000000 00000000 d409c428 d409c428
> d657db18 d409c428
> [ 6626.005088] 3ec0: 00000000 c24b0000 ffffff9c d55e3f4c d55e3f14 d55e3ee0
> c033d7b0 c033d1b8
> [ 6626.005732] 3ee0: c0c01964 c0180050 d55e3f14 d55e3ef8 c029e870 00000000
> d409c428 d6546558
> [ 6626.006382] 3f00: d55e3f58 00000000 d55e3f34 d55e3f18 c0291f04 c033d764
> 00000000 00000001
> [ 6626.007032] 3f20: 00000000 d55e3f58 d55e3f94 d55e3f38 c0293d70 c0291ea0
> d55e3f58 d55e3f4c
> [ 6626.007679] 3f40: 00000000 0090abb0 d5467800 00000000 d6dd0110 d6546558
> f3bc423c 00000012
> [ 6626.008326] 3f60: c24b0019 80808080 00000000 015ce1b0 0090abb0 00d8d670
> 00000028 c01011e4
> [ 6626.008971] 3f80: d55e2000 00000000 d55e3fa4 d55e3f98 c0294544 c0293c44
> 00000000 d55e3fa8
> [ 6626.009620] 3fa0: c0101000 c0294530 015ce1b0 0090abb0 0090abb0 000002a8
> 7d5a8800 7d5a8800
> [ 6626.010264] 3fc0: 015ce1b0 0090abb0 00d8d670 00000028 0048eb80 00487344
> 015eb160 004a6c10
> [ 6626.010912] 3fe0: 004a6c8c bede3c0c 0048149d b6ecc6b8 600f0030 0090abb0
> 00000000 00000000
> [ 6626.011577] [<c033b960>] (dx_probe) from [<c033d568>]
> (ext4_find_entry+0x3bc/0x5ac)
> [ 6626.012198] [<c033d568>] (ext4_find_entry) from [<c033d7b0>]
> (ext4_lookup+0x58/0x1f4)
> [ 6626.012844] [<c033d7b0>] (ext4_lookup) from [<c0291f04>]
> (__lookup_hash+0x70/0x9c)
> [ 6626.013468] [<c0291f04>] (__lookup_hash) from [<c0293d70>] (do_rmdir+0x138/0x1b8)
> [ 6626.014071] [<c0293d70>] (do_rmdir) from [<c0294544>] (SyS_rmdir+0x20/0x24)
> [ 6626.014642] [<c0294544>] (SyS_rmdir) from [<c0101000>]
> (ret_fast_syscall+0x0/0x54)
> [ 6626.015231] Exception stack(0xd55e3fa8 to 0xd55e3ff0)
> [ 6626.015656] 3fa0: 015ce1b0 0090abb0 0090abb0 000002a8
> 7d5a8800 7d5a8800
> [ 6626.016302] 3fc0: 015ce1b0 0090abb0 00d8d670 00000028 0048eb80 00487344
> 015eb160 004a6c10
> [ 6626.035930] 3fe0: 004a6c8c bede3c0c 0048149d b6ecc6b8
> [ 6626.055341] Code: e1a07000 e5840000 8a000078 e590601c (e5d6301c)
> [ 6626.075632] ---[ end trace 034f3552437a92bc ]---
>


2018-03-01 08:55:37

by Adrian Hunter

[permalink] [raw]
Subject: EXT4 Oops (Re: [PATCH V15 06/22] mmc: block: Add blk-mq support)

On 27/02/18 11:28, Adrian Hunter wrote:
> On 26/02/18 23:48, Dmitry Osipenko wrote:
>> But still something is wrong... I've been getting occasional EXT4 Ooops's, like
>> the one below, and __wait_on_bit() is always figuring in the stacktrace. It
>> never happened with blk-mq disabled, though it could be a coincidence and
>> actually unrelated to blk-mq patches.
>
> I can't think how an IO driver could cause that.
>
> cc'ing ext4 mailing list for more advice.

+ Ted and Andreas

>
>>
>>
>> [ 6625.992337] Unable to handle kernel NULL pointer dereference at virtual
>> address 0000001c
>> [ 6625.993004] pgd = 00b30c03
>> [ 6625.993257] [0000001c] *pgd=00000000
>> [ 6625.993594] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
>> [ 6625.994022] Modules linked in:
>> [ 6625.994326] CPU: 1 PID: 19355 Comm: dpkg Not tainted
>> 4.16.0-rc2-next-20180220-00095-ge9c9f5689a84-dirty #2090
>> [ 6625.995078] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
>> [ 6625.995595] PC is at dx_probe+0x68/0x684
>> [ 6625.995947] LR is at __wait_on_bit+0xac/0xc8
>> [ 6625.996307] pc : [<c033b960>] lr : [<c0bfbfd4>] psr: 800f0013
>> [ 6625.996806] sp : d55e3df0 ip : c0170e88 fp : d55e3e44
>> [ 6625.997227] r10: d55e3f4c r9 : d55e3e70 r8 : 00000000
>> [ 6625.997650] r7 : c4e13240 r6 : 00000000 r5 : d657db18 r4 : d55e3e8c
>> [ 6625.998165] r3 : 0000007b r2 : d5830800 r1 : d5831000 r0 : c4e13240
>> [ 6625.998686] Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
>> [ 6625.999246] Control: 10c5387d Table: 0a63004a DAC: 00000051
>> [ 6625.999710] Process dpkg (pid: 19355, stack limit = 0x139a48b6)
>> [ 6626.000184] Stack: (0xd55e3df0 to 0xd55e4000)
>> [ 6626.000560] 3de0: 000002e9 d55e3e00
>> c0c01964 c0278c70
>> [ 6626.001209] 3e00: d55e3e24 014000c0 c04f3580 c0c01958 d55e3e90 801a001a
>> d55e3e3c 00000012
>> [ 6626.001854] 3e20: d5830800 00000000 d657db18 c24b0000 d55e3e70 d55e3f4c
>> d55e3edc d55e3e48
>> [ 6626.002502] 3e40: c033d568 c033b904 00000000 600f0013 c029e640 d6cf3540
>> ffffe000 00000000
>> [ 6626.003150] 3e60: 00076e99 d55e3ef4 d55e3e8c d5830800 d409c440 d409c454
>> 00000012 c029e640
>> [ 6626.003795] 3e80: d55e3ec4 d55e3e90 c02797b4 c4e13240 00000000 00000000
>> 00000000 00000000
>> [ 6626.004442] 3ea0: 00000000 00000000 00000000 00000000 d409c428 d409c428
>> d657db18 d409c428
>> [ 6626.005088] 3ec0: 00000000 c24b0000 ffffff9c d55e3f4c d55e3f14 d55e3ee0
>> c033d7b0 c033d1b8
>> [ 6626.005732] 3ee0: c0c01964 c0180050 d55e3f14 d55e3ef8 c029e870 00000000
>> d409c428 d6546558
>> [ 6626.006382] 3f00: d55e3f58 00000000 d55e3f34 d55e3f18 c0291f04 c033d764
>> 00000000 00000001
>> [ 6626.007032] 3f20: 00000000 d55e3f58 d55e3f94 d55e3f38 c0293d70 c0291ea0
>> d55e3f58 d55e3f4c
>> [ 6626.007679] 3f40: 00000000 0090abb0 d5467800 00000000 d6dd0110 d6546558
>> f3bc423c 00000012
>> [ 6626.008326] 3f60: c24b0019 80808080 00000000 015ce1b0 0090abb0 00d8d670
>> 00000028 c01011e4
>> [ 6626.008971] 3f80: d55e2000 00000000 d55e3fa4 d55e3f98 c0294544 c0293c44
>> 00000000 d55e3fa8
>> [ 6626.009620] 3fa0: c0101000 c0294530 015ce1b0 0090abb0 0090abb0 000002a8
>> 7d5a8800 7d5a8800
>> [ 6626.010264] 3fc0: 015ce1b0 0090abb0 00d8d670 00000028 0048eb80 00487344
>> 015eb160 004a6c10
>> [ 6626.010912] 3fe0: 004a6c8c bede3c0c 0048149d b6ecc6b8 600f0030 0090abb0
>> 00000000 00000000
>> [ 6626.011577] [<c033b960>] (dx_probe) from [<c033d568>]
>> (ext4_find_entry+0x3bc/0x5ac)
>> [ 6626.012198] [<c033d568>] (ext4_find_entry) from [<c033d7b0>]
>> (ext4_lookup+0x58/0x1f4)
>> [ 6626.012844] [<c033d7b0>] (ext4_lookup) from [<c0291f04>]
>> (__lookup_hash+0x70/0x9c)
>> [ 6626.013468] [<c0291f04>] (__lookup_hash) from [<c0293d70>] (do_rmdir+0x138/0x1b8)
>> [ 6626.014071] [<c0293d70>] (do_rmdir) from [<c0294544>] (SyS_rmdir+0x20/0x24)
>> [ 6626.014642] [<c0294544>] (SyS_rmdir) from [<c0101000>]
>> (ret_fast_syscall+0x0/0x54)
>> [ 6626.015231] Exception stack(0xd55e3fa8 to 0xd55e3ff0)
>> [ 6626.015656] 3fa0: 015ce1b0 0090abb0 0090abb0 000002a8
>> 7d5a8800 7d5a8800
>> [ 6626.016302] 3fc0: 015ce1b0 0090abb0 00d8d670 00000028 0048eb80 00487344
>> 015eb160 004a6c10
>> [ 6626.035930] 3fe0: 004a6c8c bede3c0c 0048149d b6ecc6b8
>> [ 6626.055341] Code: e1a07000 e5840000 8a000078 e590601c (e5d6301c)
>> [ 6626.075632] ---[ end trace 034f3552437a92bc ]---
>>
>
>

Subject: Re: EXT4 Oops (Re: [PATCH V15 06/22] mmc: block: Add blk-mq support)

On Thu, Mar 1, 2018 at 12:55 AM, Adrian Hunter <[email protected]> wrote:
> On 27/02/18 11:28, Adrian Hunter wrote:
>> On 26/02/18 23:48, Dmitry Osipenko wrote:
>>> But still something is wrong... I've been getting occasional EXT4 Ooops's, like
>>> the one below, and __wait_on_bit() is always figuring in the stacktrace. It
>>> never happened with blk-mq disabled, though it could be a coincidence and
>>> actually unrelated to blk-mq patches.
>>
>> I can't think how an IO driver could cause that.

Probably it is not wise to place all your eggs (data) in one basket
(ext4) and diversify to viable alternatives which won't be affected by
UNIX 2038 year date problem, likewise?
< https://metztli.it/blog/index.php/amatl/reiser-nahui/reiser4-filesystem-and-the-unix
>

>>
>> cc'ing ext4 mailing list for more advice.
>
> + Ted and Andreas
>
>>
>>>
>>>
>>> [ 6625.992337] Unable to handle kernel NULL pointer dereference at virtual
>>> address 0000001c
>>> [ 6625.993004] pgd = 00b30c03
>>> [ 6625.993257] [0000001c] *pgd=00000000
>>> [ 6625.993594] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
>>> [ 6625.994022] Modules linked in:
>>> [ 6625.994326] CPU: 1 PID: 19355 Comm: dpkg Not tainted
>>> 4.16.0-rc2-next-20180220-00095-ge9c9f5689a84-dirty #2090
>>> [ 6625.995078] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
>>> [ 6625.995595] PC is at dx_probe+0x68/0x684
>>> [ 6625.995947] LR is at __wait_on_bit+0xac/0xc8
>>> [ 6625.996307] pc : [<c033b960>] lr : [<c0bfbfd4>] psr: 800f0013
>>> [ 6625.996806] sp : d55e3df0 ip : c0170e88 fp : d55e3e44
>>> [ 6625.997227] r10: d55e3f4c r9 : d55e3e70 r8 : 00000000
>>> [ 6625.997650] r7 : c4e13240 r6 : 00000000 r5 : d657db18 r4 : d55e3e8c
>>> [ 6625.998165] r3 : 0000007b r2 : d5830800 r1 : d5831000 r0 : c4e13240
>>> [ 6625.998686] Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
>>> [ 6625.999246] Control: 10c5387d Table: 0a63004a DAC: 00000051
>>> [ 6625.999710] Process dpkg (pid: 19355, stack limit = 0x139a48b6)
>>> [ 6626.000184] Stack: (0xd55e3df0 to 0xd55e4000)
>>> [ 6626.000560] 3de0: 000002e9 d55e3e00
>>> c0c01964 c0278c70
>>> [ 6626.001209] 3e00: d55e3e24 014000c0 c04f3580 c0c01958 d55e3e90 801a001a
>>> d55e3e3c 00000012
>>> [ 6626.001854] 3e20: d5830800 00000000 d657db18 c24b0000 d55e3e70 d55e3f4c
>>> d55e3edc d55e3e48
>>> [ 6626.002502] 3e40: c033d568 c033b904 00000000 600f0013 c029e640 d6cf3540
>>> ffffe000 00000000
>>> [ 6626.003150] 3e60: 00076e99 d55e3ef4 d55e3e8c d5830800 d409c440 d409c454
>>> 00000012 c029e640
>>> [ 6626.003795] 3e80: d55e3ec4 d55e3e90 c02797b4 c4e13240 00000000 00000000
>>> 00000000 00000000
>>> [ 6626.004442] 3ea0: 00000000 00000000 00000000 00000000 d409c428 d409c428
>>> d657db18 d409c428
>>> [ 6626.005088] 3ec0: 00000000 c24b0000 ffffff9c d55e3f4c d55e3f14 d55e3ee0
>>> c033d7b0 c033d1b8
>>> [ 6626.005732] 3ee0: c0c01964 c0180050 d55e3f14 d55e3ef8 c029e870 00000000
>>> d409c428 d6546558
>>> [ 6626.006382] 3f00: d55e3f58 00000000 d55e3f34 d55e3f18 c0291f04 c033d764
>>> 00000000 00000001
>>> [ 6626.007032] 3f20: 00000000 d55e3f58 d55e3f94 d55e3f38 c0293d70 c0291ea0
>>> d55e3f58 d55e3f4c
>>> [ 6626.007679] 3f40: 00000000 0090abb0 d5467800 00000000 d6dd0110 d6546558
>>> f3bc423c 00000012
>>> [ 6626.008326] 3f60: c24b0019 80808080 00000000 015ce1b0 0090abb0 00d8d670
>>> 00000028 c01011e4
>>> [ 6626.008971] 3f80: d55e2000 00000000 d55e3fa4 d55e3f98 c0294544 c0293c44
>>> 00000000 d55e3fa8
>>> [ 6626.009620] 3fa0: c0101000 c0294530 015ce1b0 0090abb0 0090abb0 000002a8
>>> 7d5a8800 7d5a8800
>>> [ 6626.010264] 3fc0: 015ce1b0 0090abb0 00d8d670 00000028 0048eb80 00487344
>>> 015eb160 004a6c10
>>> [ 6626.010912] 3fe0: 004a6c8c bede3c0c 0048149d b6ecc6b8 600f0030 0090abb0
>>> 00000000 00000000
>>> [ 6626.011577] [<c033b960>] (dx_probe) from [<c033d568>]
>>> (ext4_find_entry+0x3bc/0x5ac)
>>> [ 6626.012198] [<c033d568>] (ext4_find_entry) from [<c033d7b0>]
>>> (ext4_lookup+0x58/0x1f4)
>>> [ 6626.012844] [<c033d7b0>] (ext4_lookup) from [<c0291f04>]
>>> (__lookup_hash+0x70/0x9c)
>>> [ 6626.013468] [<c0291f04>] (__lookup_hash) from [<c0293d70>] (do_rmdir+0x138/0x1b8)
>>> [ 6626.014071] [<c0293d70>] (do_rmdir) from [<c0294544>] (SyS_rmdir+0x20/0x24)
>>> [ 6626.014642] [<c0294544>] (SyS_rmdir) from [<c0101000>]
>>> (ret_fast_syscall+0x0/0x54)
>>> [ 6626.015231] Exception stack(0xd55e3fa8 to 0xd55e3ff0)
>>> [ 6626.015656] 3fa0: 015ce1b0 0090abb0 0090abb0 000002a8
>>> 7d5a8800 7d5a8800
>>> [ 6626.016302] 3fc0: 015ce1b0 0090abb0 00d8d670 00000028 0048eb80 00487344
>>> 015eb160 004a6c10
>>> [ 6626.035930] 3fe0: 004a6c8c bede3c0c 0048149d b6ecc6b8
>>> [ 6626.055341] Code: e1a07000 e5840000 8a000078 e590601c (e5d6301c)
>>> [ 6626.075632] ---[ end trace 034f3552437a92bc ]---
>>>
>>
>>
>

Sorry if I intrude but just my 2¢.


Best Professional Regards.

--
Jose R R
http://metztli.it
---------------------------------------------------------------------------------------------
Download Metztli Reiser4: Debian Stretch w/ Linux 4.14 AMD64
---------------------------------------------------------------------------------------------
feats ZSTD compression https://sf.net/projects/metztli-reiser4/
-------------------------------------------------------------------------------------------
Official current Reiser4 resources: https://reiser4.wiki.kernel.org/

2018-03-01 16:04:18

by Theodore Ts'o

[permalink] [raw]
Subject: Re: EXT4 Oops (Re: [PATCH V15 06/22] mmc: block: Add blk-mq support)

On Thu, Mar 01, 2018 at 10:55:37AM +0200, Adrian Hunter wrote:
> On 27/02/18 11:28, Adrian Hunter wrote:
> > On 26/02/18 23:48, Dmitry Osipenko wrote:
> >> But still something is wrong... I've been getting occasional EXT4 Ooops's, like
> >> the one below, and __wait_on_bit() is always figuring in the stacktrace. It
> >> never happened with blk-mq disabled, though it could be a coincidence and
> >> actually unrelated to blk-mq patches.
> >
> >> [ 6625.992337] Unable to handle kernel NULL pointer dereference at virtual
> >> address 0000001c
> >> [ 6625.993004] pgd = 00b30c03
> >> [ 6625.993257] [0000001c] *pgd=00000000
> >> [ 6625.993594] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
> >> [ 6625.994022] Modules linked in:
> >> [ 6625.994326] CPU: 1 PID: 19355 Comm: dpkg Not tainted
> >> 4.16.0-rc2-next-20180220-00095-ge9c9f5689a84-dirty #2090
> >> [ 6625.995078] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
> >> [ 6625.995595] PC is aht dx_probe+0x68/0x684
> >> [ 6625.995947] LR is at __wait_on_bit+0xac/0xc8

This doesn't seem to make sense; the PC is where we are currently
executing, and LR is the "Link Register" where the flow of control
will be returning after the current function returns, right? Well,
dx_probe should *not* be returning to __wait_on_bit(). So this just
seems.... weird.

Ignoring the LR register, this stack trace looks sane... I can't see
which pointer could be NULL and getting dereferenced, though. How
easily can you reproduce the problem? Can you either (a) translate
the PC into a line number, or better yet, if you can reproduce, add a
series of BUG_ON's so we can see what's going on?

+ BUG_ON(frame);
memset(frame_in, 0, EXT4_HTREE_LEVEL * sizeof(frame_in[0]));
frame->bh = ext4_read_dirblock(dir, 0, INDEX);
if (IS_ERR(frame->bh))
return (struct dx_frame *) frame->bh;

+ BUG_ON(frame->bh);
+ BUG_ON(frame->bh->b_data);
root = (struct dx_root *) frame->bh->b_data;
if (root->info.hash_version != DX_HASH_TEA &&
root->info.hash_version != DX_HASH_HALF_MD4 &&
root->info.hash_version != DX_HASH_LEGACY) {

These are "could never" happen scenarios from looking at the code, but
that will help explain what is going on.

If this is reliably only happening with mq, the only way I could see
that if is something is returning an error when it previously wasn't.
This isn't a problem we're seeing with any of our testing, though.

Cheers,

- Ted

2018-03-01 16:07:05

by Theodore Ts'o

[permalink] [raw]
Subject: Re: EXT4 Oops (Re: [PATCH V15 06/22] mmc: block: Add blk-mq support)

On Thu, Mar 01, 2018 at 01:15:24AM -0800, Jose R R wrote:
> Probably it is not wise to place all your eggs (data) in one basket
> (ext4) and diversify to viable alternatives which won't be affected by
> UNIX 2038 year date problem, likewise?
> < https://metztli.it/blog/index.php/amatl8/reiser-nahui/reiser4-filesystem-and-the-unix
> >

All of the modern file systems (btrfs, ext4, f2fs, xfs, etc.) are fine
with respect to the 2038 problem.

- Ted

2018-03-01 20:20:16

by Andreas Dilger

[permalink] [raw]
Subject: Re: EXT4 Oops (Re: [PATCH V15 06/22] mmc: block: Add blk-mq support)


On Mar 1, 2018, at 9:04 AM, Theodore Ts'o <[email protected]> wrote:
> This doesn't seem to make sense; the PC is where we are currently
> executing, and LR is the "Link Register" where the flow of control
> will be returning after the current function returns, right? Well,
> dx_probe should *not* be returning to __wait_on_bit(). So this just
> seems.... weird.
>
> Ignoring the LR register, this stack trace looks sane... I can't see
> which pointer could be NULL and getting dereferenced, though. How
> easily can you reproduce the problem? Can you either (a) translate
> the PC into a line number, or better yet, if you can reproduce, add a
> series of BUG_ON's so we can see what's going on?
>
> + BUG_ON(frame);

I think you mean:
BUG_ON(frame == NULL);
or
BUG_ON(!frame);


> memset(frame_in, 0, EXT4_HTREE_LEVEL * sizeof(frame_in[0]));
> frame->bh = ext4_read_dirblock(dir, 0, INDEX);
> if (IS_ERR(frame->bh))
> return (struct dx_frame *) frame->bh;
>
> + BUG_ON(frame->bh);
> + BUG_ON(frame->bh->b_data);

Same here.

BUG_ON(frame->bh == NULL);
BUG_ON(frame->bh->b_data == NULL);

This is why I don't like implicit "is NULL" or "is non-zero" usage. Lustre
used to require "== NULL" or "!= NULL" to avoid bugs like this, but had to
abandon that because of upstream code style.

> root = (struct dx_root *) frame->bh->b_data;
> if (root->info.hash_version != DX_HASH_TEA &&
> root->info.hash_version != DX_HASH_HALF_MD4 &&
> root->info.hash_version != DX_HASH_LEGACY) {
>
> These are "could never" happen scenarios from looking at the code, but
> that will help explain what is going on.
>
> If this is reliably only happening with mq, the only way I could see
> that if is something is returning an error when it previously wasn't.
> This isn't a problem we're seeing with any of our testing, though.
>
> Cheers,
>
> - Ted
>


Cheers, Andreas






Attachments:
signature.asc (873.00 B)
Message signed with OpenPGP

2018-03-02 16:39:25

by Dmitry Osipenko

[permalink] [raw]
Subject: Re: EXT4 Oops (Re: [PATCH V15 06/22] mmc: block: Add blk-mq support)

On 01.03.2018 23:20, Andreas Dilger wrote:
>
> On Mar 1, 2018, at 9:04 AM, Theodore Ts'o <[email protected]> wrote:
>> This doesn't seem to make sense; the PC is where we are currently
>> executing, and LR is the "Link Register" where the flow of control
>> will be returning after the current function returns, right? Well,
>> dx_probe should *not* be returning to __wait_on_bit(). So this just
>> seems.... weird.
>>
>> Ignoring the LR register, this stack trace looks sane... I can't see
>> which pointer could be NULL and getting dereferenced, though. How
>> easily can you reproduce the problem? Can you either (a) translate
>> the PC into a line number, or better yet, if you can reproduce, add a
>> series of BUG_ON's so we can see what's going on?

Ted, thank you for the suggestion. I don't have a bug-reproducer, it happens
only under some IO load and quite randomly. I've applied the BUG_ON()'s, but it
may take some time to catch the bug again.

>> + BUG_ON(frame);
>
> I think you mean:
> BUG_ON(frame == NULL);
> or
> BUG_ON(!frame);
>
>
>> memset(frame_in, 0, EXT4_HTREE_LEVEL * sizeof(frame_in[0]));
>> frame->bh = ext4_read_dirblock(dir, 0, INDEX);
>> if (IS_ERR(frame->bh))
>> return (struct dx_frame *) frame->bh;
>>
>> + BUG_ON(frame->bh);
>> + BUG_ON(frame->bh->b_data);
>
> Same here.
>
> BUG_ON(frame->bh == NULL);
> BUG_ON(frame->bh->b_data == NULL);
>
> This is why I don't like implicit "is NULL" or "is non-zero" usage. Lustre
> used to require "== NULL" or "!= NULL" to avoid bugs like this, but had to
> abandon that because of upstream code style.

Well spotted, thanks Andreas.

>> root = (struct dx_root *) frame->bh->b_data;
>> if (root->info.hash_version != DX_HASH_TEA &&
>> root->info.hash_version != DX_HASH_HALF_MD4 &&
>> root->info.hash_version != DX_HASH_LEGACY) {
>>
>> These are "could never" happen scenarios from looking at the code, but
>> that will help explain what is going on.
>>
>> If this is reliably only happening with mq, the only way I could see
>> that if is something is returning an error when it previously wasn't.
>> This isn't a problem we're seeing with any of our testing, though.