Messages in this thread | | | Date | Tue, 21 Apr 2015 20:42:09 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH v6 0/6] arm64: Add kernel probes (kprobes) support |
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(2015/04/21 5:19), David Long wrote: > From: "David A. Long" <dave.long@linaro.org> > > This patchset is heavily based on Sandeepa Prabhu's ARM v8 kprobes patches, > first seen in October 2013. This version attempts to address concerns raised by > reviewers and also fixes problems discovered during testing. > > This patchset adds support for kernel probes(kprobes), jump probes(jprobes) > and return probes(kretprobes) support for ARM64. > > The kprobes mechanism makes use of software breakpoint and single stepping > support available in the ARM v8 kernel. > [...] > Changes since v5 include: > > 1) Replaced installation of breakpoint hook with direct call from the > handlers in debug-monitors.c, as requested. > 2) Reject probing of instructions that read the interrupt mask, in > addition to instructions that set it. > 3) Cleaned up comments describing usage of Debug Mask. > 4) Added KPROBE_REENTER case in reenter_kprobe. > 5) Corrected the ifdef'd definitions for notify_page_fault() to be > consistent when KPROBES is not configed. > 6) Changed "cpsr" to "pstate" for HAVE_REGS_AND_STACK_ACCESS_API feature. > 7) Added back in missing new files in previous patch. > 8) Changed two instances of pr_warning() to pr_warn().
Looks OK to me:) BTW, have you tried to build and test this with CONFIG_KPROBE_EVENT? If so, you can also test it by tools/testing/selftests/ftrace/ftracetest.
> Note that there seems to be at least a potential issue with kprobes > on multiple (possibly all) platforms having to do with use of kfree > inside of the kretprobes trampoline handler. This has manifested > occasionally in systemtap testing on arm64. There does not appear to > be an simple solution to the problem.
No, trampoline handler must call recycle_rp_inst() instead of kfree to return kretprobe instance to the pool. Hmm, I should look into it.
Thank you,
-- Masami HIRAMATSU Linux Technology Research Center, System Productivity Research Dept. Center for Technology Innovation - Systems Engineering Hitachi, Ltd., Research & Development Group E-mail: masami.hiramatsu.pt@hitachi.com
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