running custom commands during sysupgrade -

[Reiner Karlsberg]

Am 22.11.2020 um 19:23 schrieb Alberto Bursi:
> 
> 
> On 22/11/20 18:07, Hannu Nyman wrote:
>> Adrian Schmutzler wrote at Fri Oct 16 19:15:38 EDT 2020:
>>
>>  > Fortunately, and I don't fully understand why, we were able to drive this to effectively zero by simply running
>>  > echo 3 > /proc/sys/vm/drop_caches
>>  > directly before sysupgrade. Out of a few hundred upgrades since then, I haven't had a single soft-brick. I do 
>> occasionally have the situation that the device reboots into the old firmware again (i.e. upgrade failed in an early 
>> stage), but for some reason the soft-bricks were completely gone.
>>
>> I have stumbled into similar "boot to the old firmware" symptom with my old WNDR3700v2 with 64 MB RAM.
>> I have not been able to reproduce the problem in WNDR3800 that has 128 MB RAM but it otherwise identical, (and has 
>> serial cable connected).
>>
>> Sysupgrade in WNDR3700v2 used to regularly
>> * fail, if sysupgrade was run after the router had been running a few days
>> * succeed with the same image, when sysupgrade was re-run right after the first failure (and automatic reboot)
>>
>> To avoid failure I have patched the sysupgrade script components itself, and I have not seen the problem any more. 
>> Patched files are /lib/upgrade/common.sh and /lib/upgrade/stage2
>>
>> I am not sure if those insertion locations are quite optimal, but so far the approach has worked
>>
>>
>> --- a/package/base-files/files/lib/upgrade/common.sh
>> +++ b/package/base-files/files/lib/upgrade/common.sh
>> @@ -297,6 +297,7 @@ indicate_upgrade() {
>>   # $(2): (optional) pipe command to extract firmware, e.g. dd bs=n skip=m
>>   default_do_upgrade() {
>>       sync
>> +    echo 3 > /proc/sys/vm/drop_caches
>>       if [ -n "$UPGRADE_BACKUP" ]; then
>>           get_image "$1" "$2" | mtd $MTD_ARGS $MTD_CONFIG_ARGS -j "$UPGRADE_BACKUP" write - "${PART_NAME:-image}"
>>       else
>> --- a/package/base-files/files/lib/upgrade/stage2
>> +++ b/package/base-files/files/lib/upgrade/stage2
>> @@ -123,6 +123,7 @@ kill_remaining KILL 1
>>
>>   sleep 1
>>
>> +echo 3 > /proc/sys/vm/drop_caches
>>
>>   if [ -n "$IMAGE" ] && type 'platform_pre_upgrade' >/dev/null 2>/dev/null; then
>>       platform_pre_upgrade "$IMAGE"
>>
>>
> 
> would it make sense to propose/accept this change in master?
> I don't see any drawback to just have this as the default
> 
> -Alberto
> 
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+1. Doing this for more than a year, already. And having practically no issues any more.

I also explicitly  unmount all mounted mass storage. I.g. SSD, or swap-device, before sysupgrade.

Happy, that somebody finally cares about it. My bugreports, also proposing fix from above,
were fruitless, so far.

Cheers,

Reiner