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Groups > linux.kernel > #1722556

Re: [PATCH] perf probe: Fix kprobe blacklist checking condition

From Arnaldo Carvalho de Melo <acme@kernel.org>
Newsgroups linux.kernel
Subject Re: [PATCH] perf probe: Fix kprobe blacklist checking condition
Date 2017-08-29 17:00 +0200
Message-ID <ujQ9I-3UP-17@gated-at.bofh.it> (permalink)
References <ujOrg-33K-23@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Em Tue, Aug 29, 2017 at 08:57:23PM +0800, Li Bin escreveu:
> The commit 9aaf5a5("perf probe: Check kprobes blacklist
> when adding new events"), perf probe supports checking
> the blacklist of the fuctions which can not be probed.
> But the checking condition is wrong, that the end_addr
> of the symbol which is the start_addr of the next symbol
> can't be included.

Applied, with the following committer notes added:

    Committer notes:
    
    IOW make it match its kernel counterpart in kernel/kprobes.c:
    
      bool within_kprobe_blacklist(unsigned long addr)
    
    Each entry have as its end address not its end address, but the first
    address _outside_ that symbol, which for related functions, is the first
    address of the next symbol, like these from kernel/trace/trace_probe.c:
    
    0xffffffffbd198df0-0xffffffffbd198e40   print_type_u8
    0xffffffffbd198e40-0xffffffffbd198e90   print_type_u16
    0xffffffffbd198e90-0xffffffffbd198ee0   print_type_u32
    0xffffffffbd198ee0-0xffffffffbd198f30   print_type_u64
    0xffffffffbd198f30-0xffffffffbd198f80   print_type_s8
    0xffffffffbd198f80-0xffffffffbd198fd0   print_type_s16
    0xffffffffbd198fd0-0xffffffffbd199020   print_type_s32
    0xffffffffbd199020-0xffffffffbd199070   print_type_s64
    0xffffffffbd199070-0xffffffffbd1990c0   print_type_x8
    0xffffffffbd1990c0-0xffffffffbd199110   print_type_x16
    0xffffffffbd199110-0xffffffffbd199160   print_type_x32
    0xffffffffbd199160-0xffffffffbd1991b0   print_type_x64
    
    But not always:
    
    0xffffffffbd1997b0-0xffffffffbd1997c0   fetch_kernel_stack_address (kernel/trace/trace_probe.c)
    0xffffffffbd1c57f0-0xffffffffbd1c58b0   __context_tracking_enter   (kernel/context_tracking.c)
    
    Fixes: 9aaf5a5f479b ("perf probe: Check kprobes blacklist when adding new events")

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Thread

[PATCH] perf probe: Fix kprobe blacklist checking condition Li Bin <huawei.libin@huawei.com> - 2017-08-29 15:10 +0200
  Re: [PATCH] perf probe: Fix kprobe blacklist checking condition Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-08-29 17:00 +0200
  [tip:perf/core] perf probe: Fix kprobe blacklist checking condition tip-bot for Li Bin <tipbot@zytor.com> - 2017-08-29 23:30 +0200
  Re: [PATCH] perf probe: Fix kprobe blacklist checking condition Masami Hiramatsu <mhiramat@kernel.org> - 2017-08-30 14:30 +0200

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