Hi Jim: * Jim Cromie <jim.cromie at gmail.com> [2006-07-11 12:33:33 -0600]: > > from the 18-rc1-mm1 announcement: > > - We're getting a relatively large number of crash reports coming out of the > core sysfs/kobject/driver/bus code, and they're all really hard to diagnose. > > I am suspecting that what's happening is that some registration functions > are failing and the caller is ignoring that failure. The code proceeds and > crashes much later, in obscure ways. > > All these functions return error codes, and we're not checking them. We > should. So there's a patch which marks all these things as __must_check, > which causes around 1,500 new warnings. > > These are all bugs and they all need to be fixed. > > > > Many of these 1500 are from lm-sensors modules; > for example - a single function - device_create_file(), > is called 1027 times, and 'every' one is a void context return. > > grep device_create_file drivers/hwmon/*.c > > So, what kinds of errors are possible here ? > and what should we do if they occur ? > does it ever happen that only 1 create fails ? > do/would we care ? (not currently) > > These Qs are somewhat rhetorical, theyre at least a heads-up. I can't resist answering rhetorical questions. ;) At least in the context of what Andrew wrote, the calls to device_create_file() in the hwmon drivers are not the problem. AFAICT, if one or more sysfs files fail to be created, the worst that might happen is that *maybe* sensors(1) could crash. Offhand, I can't see how missing sysfs files could lead to a kernel crash. At any rate, yes, they're still bugs. OTOH, there is a real need to review some of the error checking in the I2C core - where ignoring status can and does cause kernel panics. See some recent patches by both Jean and me for examples... and there are more. > FWIW, device_remove_file() is only called 9 times. > This doesnt seem to be a problem though, or we'd have heard it by now. > Specifically - hwmon/pc87360 appears to clean up after itself, > (or rather sysfs core code does), without any calls to device_remove_file() > > soekris:/sys/bus/i2c/devices# ls > 9191-6620@ > soekris:/sys/bus/i2c/devices# rmmod pc87360 > soekris:/sys/bus/i2c/devices# ls > soekris:/sys/bus/i2c/devices# > > > Ive gone ahead and worked up a patch against pc87360 to > count-errors-and-warn, which should suffice, at least for short term. (Hopefully) I'll take a look at this later today. Regards, -- Mark M. Hoffman mhoffman at lightlink.com
