mainlining shenanigans
4b335e1e0d
On powerpc, 'perf trace' is crashing with a SIGSEGV when trying to process a perf.data file created with 'perf trace record -p': #0 0x00000001225b8988 in syscall_arg__scnprintf_augmented_string <snip> at builtin-trace.c:1492 #1 syscall_arg__scnprintf_filename <snip> at builtin-trace.c:1492 #2 syscall_arg__scnprintf_filename <snip> at builtin-trace.c:1486 #3 0x00000001225bdd9c in syscall_arg_fmt__scnprintf_val <snip> at builtin-trace.c:1973 #4 syscall__scnprintf_args <snip> at builtin-trace.c:2041 #5 0x00000001225bff04 in trace__sys_enter <snip> at builtin-trace.c:2319 That points to the below code in tools/perf/builtin-trace.c: /* * If this is raw_syscalls.sys_enter, then it always comes with the 6 possible * arguments, even if the syscall being handled, say "openat", uses only 4 arguments * this breaks syscall__augmented_args() check for augmented args, as we calculate * syscall->args_size using each syscalls:sys_enter_NAME tracefs format file, * so when handling, say the openat syscall, we end up getting 6 args for the * raw_syscalls:sys_enter event, when we expected just 4, we end up mistakenly * thinking that the extra 2 u64 args are the augmented filename, so just check * here and avoid using augmented syscalls when the evsel is the raw_syscalls one. */ if (evsel != trace->syscalls.events.sys_enter) augmented_args = syscall__augmented_args(sc, sample, &augmented_args_size, trace->raw_augmented_syscalls_args_size); As the comment points out, we should not be trying to augment the args for raw_syscalls. However, when processing a perf.data file, we are not initializing those properly. Fix the same. Reported-by: Claudio Carvalho <cclaudio@linux.ibm.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lore.kernel.org/lkml/20220707090900.572584-1-naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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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.