Messages in this thread | | | From | Srikar Dronamraju <> | Date | Mon, 11 Jan 2010 17:55:21 +0530 | Subject | [RFC] [PATCH 0/7] UBP, XOL and Uprobes |
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Hi,
This patchset implements Uprobes which enables you to dynamically break into any routine in a user space application and collect information non-disruptively. Uprobes is based on utrace and uses x86 instruction decoder.
When a uprobe is registered, Uprobes makes a copy of the probed instruction, stops the probed application, replaces the first byte(s) of the probed instruction with a breakpoint instruction and allows the probed application to continue. (Uprobes uses the same copy-on-write mechanism so that the breakpoint affects only that process.)
When a CPU hits the breakpoint instruction, Uprobes intercepts the SIGTRAP and finds the associated uprobe. It then executes the associated handler. Uprobes single-steps its copy of the probed instruction and resumes execution of the probed process at the instruction following the probepoint. Instruction copies to be single-stepped are stored in a per-process "single-step out of line (XOL) area,"
Uprobes can be used to take advantage of static markers available in user space applications.
Advantages of uprobes over conventional debugging include: 1. Non-disruptive. 2. Uses Execution out of line(XOL), 3. Much better handling of multithreaded programs because of XOL. 4. No context switch between tracer, tracee.
Here is the list of TODO Items.
- Provide a perf interface to uprobes. - Return probes. - Support for Other Architectures. - Jump optimization.
This patchset provides Subject: [RFC] [PATCH 0/7] UBP, XOL and Uprobes Subject: [RFC] [PATCH 1/7] User Space Breakpoint Assistance Layer (UBP) Subject: [RFC] [PATCH 2/7] x86 support for UBP Subject: [RFC] [PATCH 3/7] Execution out of line (XOL) Subject: [RFC] [PATCH 4/7] Uprobes Implementation Subject: [RFC] [PATCH 5/7] X86 Support for Uprobes Subject: [RFC] [PATCH 6/7] Uprobes Documentation Subject: [RFC] [PATCH 7/7] Ftrace plugin for Uprobes
This patchset is based on git://git.kernel.org/pub/scm/linux/kernel/git/frob/linux-2.6-utrace.git
If and when utrace gets accepted into tip tree or Mainline, I will rebase this patchset.
Please do provide your valuable comments.
-- Thanks and Regards Srikar
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