2bc3cf575a
To verify it found the correct variable, let's add the location expression to the debug message. $ perf --debug type-profile annotate --data-type ... ----------------------------------------------------------- find data type for 0xaf0(reg15) at schedule+0xeb CU for kernel/sched/core.c (die:0x1180523) frame base: cfa=0 fbreg=6 found "rq" in scope=3/4 (die: 0x11b6a00) type_offset=0xaf0 variable location: reg15 type='struct rq' size=0xfc0 (die:0x11892e2) ----------------------------------------------------------- find data type for 0x7bc(reg3) at tcp_get_info+0x62 CU for net/ipv4/tcp.c (die:0x7b5f516) frame base: cfa=0 fbreg=6 offset: 1980 is bigger than size: 760 check variable "sk" failed (die: 0x7b92b2c) variable location: reg3 type='struct sock' size=0x2f8 (die:0x7b63c3a) ----------------------------------------------------------- ... The first case is fine. It looked up a data type in r15 with offset of 0xaf0 at schedule+0xeb. It found the CU die and the frame base info and the variable "rq" was found in the scope 3/4. Its location is the r15 register and the type size is 0xfc0 which includes 0xaf0. But the second case is not good. It looked up a data type in rbx (reg3) with offset 0x7bc. It found a CU and the frame base which is good so far. And it also found a variable "sk" but the access offset is bigger than the type size (1980 vs. 760 or 0x7bc vs. 0x2f8). The variable has the right location (reg3) but I need to figure out why it accesses beyond what it's supposed to. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20240412183310.2518474-2-namhyung@kernel.org [ Fix the build on 32-bit by casting Dwarf_Word to (long) in pr_debug_location() ] 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 reStructuredText 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.