On Fri, 13 Jan 2017 08:58:34 -0800 Kenny Yu <[email protected]> wrote: > Previously, `create_trace_uprobe` found the *first* occurence > of the ':' character when parsing `PATH:OFFSET` for a uprobe. > However, if the path contains a ':' character, then the function > would parse the path incorrectly. Even worse, if the path does not > exist, the subsequent call to `kern_path()` would set `ret` to > `ENOENT`, leading to very cryptic errno values in user space. > > The fix is to find the *last* occurence of ':'. > > How to repro:: The write fails with "No such file or directory", suggesting > incorrectly that the `uprobe_events` file does not exist. > > $ mkdir testing && cd testing > $ cp /bin/bash . > $ cp /bin/bash ./bash:with:colon > $ echo "p:uprobes/p__root_testing_bash_0x6 /root/testing/bash:0x6" > > /sys/kernel/debug/tracing/uprobe_events # this works > $ echo "p:uprobes/p__root_testing_bash_with_colon_0x6 > /root/testing/bash:with:colon:0x6" >> /sys/kernel/debug/tracing/uprobe_events > # this doesn't > -bash: echo: write error: No such file or directory > > With the patch: > > $ echo "p:uprobes/p__root_testing_bash_0x6 /root/testing/bash:0x6" > > /sys/kernel/debug/tracing/uprobe_events # this still works > $ echo "p:uprobes/p__root_testing_bash_with_colon_0x6 > /root/testing/bash:with:colon:0x6" >> /sys/kernel/debug/tracing/uprobe_events > # this works now too! > $ cat /sys/kernel/debug/tracing/uprobe_events > p:uprobes/p__root_testing_bash_0x6 /root/testing/bash:0x0000000000000006 > p:uprobes/p__root_testing_bash_with_colon_0x6 > /root/testing/bash:with:colon:0x0000000000000006 >
Thanks! I'll add this to my queue. -- Steve
