Messages in this thread | | | From | Ramkumar Ramachandra <> | Date | Fri, 4 Oct 2013 10:22:36 +0530 | Subject | Re: [PATCH] perf tool: more user-friendly errors from trace |
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Arnaldo Carvalho de Melo wrote: > [acme@zoo ~]$ mount | grep debugfs > [acme@zoo ~]$ > [acme@zoo ~]$ perf trace usleep 1 > Is debugfs mounted? Try 'sudo mount -t debugfs nodev /sys/kernel/debug' > [acme@zoo ~]$ sudo mkdir /d > [acme@zoo ~]$ sudo mount -t debugfs nodev /d > [acme@zoo ~]$ mount | grep debugfs > nodev on /d type debugfs (rw,relatime) > [acme@zoo ~]$ > [acme@zoo ~]$ perf trace usleep 1 > Couldn't access debugfs. Try 'sudo mount -o remount,mode=755 /d' > [acme@zoo ~]$ sudo mount -o remount,mode=755 /d
On Arch, I just had to `chmod go+rx /sys/kernel/debug`, and add an entry to fstab so it works across reboots. Remounting by hand works too, but it's likely that users are more familiar with simple filesystem permissions.
> + case ENOENT: > + fputs("Is debugfs mounted? Try 'sudo mount -t debugfs nodev /sys/kernel/debug'\n", trace->output);
Doesn't an ENOENT indicate that the kernel was not compiled with debugfs support in the first place? Isn't it systemd's job to check the kernel for the feature and do the mounting?
> + case EACCES: > + fprintf(trace->output, > + "Couldn't access debugfs. Try 'sudo mount -o remount,mode=755 %s'\n", > + debugfs_mountpoint);
Instead of giving a specific line to execute, I'd prefer if the error described that the current user does not have permissions to read $debugfs in words.
Your patch splits the error into two different bits, which I like. But I prefer the wording in my original patch: so, I'll re-work my patch and re-submit.
Thanks.
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