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e8ca4f0f8c
Since @symbol variable access is not supported by uprobe event, it must be
correctly warn user instead of kernel version update.
Committer testing:
With/without the patch:
[root@quaco ~]# perf probe -x ~/bin/perf -L sigtrap_handler
<sigtrap_handler@/home/acme/git/perf-tools-next/tools/perf/tests/sigtrap.c:0>
0 sigtrap_handler(int signum __maybe_unused, siginfo_t *info, void *ucontext __maybe_unused)
1 {
2 if (!__atomic_fetch_add(&ctx.signal_count, 1, __ATOMIC_RELAXED))
3 ctx.first_siginfo = *info;
4 __atomic_fetch_sub(&ctx.tids_want_signal, syscall(SYS_gettid), __ATOMIC_RELAXED);
5 }
static void *test_thread(void *arg)
{
[root@quaco ~]# perf probe -x ~/bin/perf sigtrap_handler:4 "ctx.signal_count"
Without the patch:
[root@quaco ~]# perf probe -x ~/bin/perf sigtrap_handler:4 "ctx.signal_count"
Failed to write event: Invalid argument
Please upgrade your kernel to at least 3.14 to have access to feature @ctx
Error: Failed to add events.
[root@quaco ~]#
With the patch:
[root@quaco ~]#
Failed to write event: Invalid argument
@ctx accesses a variable by symbol name, but that is not supported for user application probe.
Error: Failed to add events.
[root@quaco ~]#
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Closes: https://lore.kernel.org/all/ZLWDEjvFjrrEJODp@kernel.org/
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/169055397023.67089.12693645664676964310.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.