eMMC Error: Kernel Remounting filesystem to read-only

dhu

Hi,

The Linux kernel 4.4.48 should have fix to kernel remounting the file system to ready only. After the reboot the eMMC (partition) again becomes read/write. The other v4.8, and v4.9 should have the fix for this issue. I tested with v4.4 but I still get the error.

2017-02-15T16:45:47.168691+00:00 kernel: [100226.108742] EXT4-fs (mmcblk0p4): Remounting filesystem read-only

For reference I have modinfo from the sdhci.ko module from Kernel.
/lib/modules/4.4.48/kernel/drivers/mmc/host # modinfo sdhci.ko
filename: /lib/modules/4.4.48/kernel/drivers/mmc/host/sdhci.ko
license: GPL
description: Secure Digital Host Controller Interface core driver
author: Pierre Ossman <pierre@ossman.eu>
srcversion: 8D2D347A491918D299D89E2
depends: mmc_core
intree: Y
parm: debug_quirks:Force certain quirks. (uint)
parm: debug_quirks2:Force certain other quirks. (uint)

/lib/modules/4.4.48/kernel/drivers/mmc/host # modinfo sdhci-acpi.ko
filename: /lib/modules/4.4.48/kernel/drivers/mmc/host/sdhci-acpi.ko
license: GPL v2
author: Adrian Hunter
description: Secure Digital Host Controller Interface ACPI driver
srcversion: 8108FAE714DF38E43712056
alias: acpi*:PNP0D40:*
alias: acpi*:INT344D:*
alias: acpi*:INT3436:*
alias: acpi*:INT33C6:*
alias: acpi*:INT33BB:*
alias: acpi*:80860F16:*
alias: acpi*:80860F14:*
alias: acpi*:80865AD0:*
alias: acpi*:80865ACC:*
alias: acpi*:80865ACA:*
depends: sdhci,mmc_core
intree: Y

/lib/modules/4.4.48/kernel/drivers/mmc/host # modinfo sdhci-pltfm.ko
filename: /lib/modules/4.4.48/kernel/drivers/mmc/host/sdhci-pltfm.ko
license: GPL v2
author: Intel Corporation
description: SDHCI platform and OF driver helper
srcversion: AC138C737DA496DE1A8AF17
depends: sdhci
intree: Y

Has anyone faced similar issue. On the forum there are people you have faced this issue.
https://up-community.org/forum/search?query=mmc0: Timeout waiting for hardware interrupt&amp;childforums=1
https://up-community.org/forum/search?query=read-only&childforums=1

dhu

The Kernel 4.4.48 does not include all the patches mentioned patched from https://www.spinics.net/lists/linux-mmc/msg40829.html
Patch 1 - Patch 3 are included. Patch 4- Patch 9 are partially or completely missing.

Affected file
drivers/mmc/core/mmc_ops.c | 25 ++++
drivers/mmc/host/sdhci.c | 278 ++++++++++++++++++++++++

---

include/linux/mmc/core.h | 1 +
3 files changed, 173 insertions(+), 131 deletions(-)

Need to test and check if adding all the patches fixes the issue.

dhu

Hi Up Team,

I applied the complete patches from: https://www.spinics.net/lists/linux-mmc/msg40829.html for this specific issue.
There is a kernel panic during boot up and the is kernel locked up. Booting is not possible with patch.
BUG: Unable to handle Kernel NULL Pointer Deference at XXXX
sdhci_send_command +037/0x350 [sdhci]

The compilation also failed due to below function called in sdhci_send_tuning()
sdhci_del_timer(host, &mrq);
I commented it out this line for the compilation to be successful and create the kernel build.

I used SuSE kernel 4.4.21-69-default for my testing/compilation. There were few patch already applied, I applied the rest and I get this error.

Can you tell me what patches you have applied to the ubilinux etc kernel?
I don’t know if anyone has tested the complete patch.
Does anyone have this issue?

Dan O'Donovan

For the ubilinux kernel, we applied patch 2 in that patch series:
https://www.spinics.net/lists/linux-mmc/msg40826.html

This is one that specifically addresses the issue we were seeing with MMC write failures triggered by tuning timeouts.

dhu

Hi Dan,

I applied the #Patch2 from www.spinics.net/lists/linux-mmc/msg40826.html to Linux 4.4.21-69-default kernel.
As of now the issue probably is resolved. I am running the regression testing and I have not seen kernel Remounting eMMC to Read-Only. If there are any new finding I surely update this thread.

Dan O'Donovan

That is good to hear, dhu. Thanks for the feedback!