On Wed, Mar 23, 2016 at 08:47:02PM +0100, Wolfram Sang wrote: > Jan reported this: > === > After enabling CONFIG_I2C_DEBUG_CORE my system was broken > (no network, console login not possible). System log was > flooded with the this message: > > ... > [ 608.052077] rtc-ds1307 0-0068: uevent > [ 608.052500] rtc-ds1307 0-0068: uevent > [ 608.052925] rtc-ds1307 0-0068: uevent > ... > > The culprit is the dev_dbg printk in the i2c uevent handler. > If this is activated (for instance by CONFIG_I2C_DEBUG_CORE) > it results in an endless loop with systemd-journald. > > This happens if user-space scans the system log and reads the uevent > file to get information about a newly created device, which seems fair > use to me. Unfortunately reading the "uevent" file uses the same > function that runs for creating the uevent for a new device, > generating the next syslog entry. > > Ideally user-space would implement a recursion detection and > after reading the same device file for the 1000th time call it a > day, but nevertheless I think we should avoid this problem by > removing the debug print completly or using another print variant. > > The same problem seems to be reported here: > https://bugs.freedesktop.org/show_bug.cgi?id=76886 > === > > His patch converted the message to pr_debug, but I think the debug can > simply go. We have other means to see code paths these days. This > enables us to clean up the function some more while we are here. > > Reported-by: Jan Glauber <jglauber@xxxxxxxxxx> > Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx> > Acked-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx> > Tested-by: Jan Glauber <jglauber@xxxxxxxxxx> Applied to for-current, thanks!
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