dfadf8b315
'DWARF unwind' 'perf test' can sometimes fail:
$ perf test -v 74
Couldn't bump rlimit(MEMLOCK), failures may take place when creating BPF maps, etc
74: Test dwarf unwind :
--- start ---
test child forked, pid 3785254
Problems creating module maps, continuing anyway...
Problems creating module maps, continuing anyway...
unwind: test__arch_unwind_sample:ip = 0x102d0ad4c (0x36ad4c)
unwind: access_mem addr 0x7fffc33128c8, val 1031c3228, offset 120
unwind: access_mem addr 0x7fffc33128d0, val 12427cc70, offset 128
<snip>
unwind: test_dwarf_unwind__krava_3:ip = 0x102b8768b (0x1e768b)
unwind: access_mem addr 0x7fffc3313048, val 7fffc3313050, offset 2040
unwind: access_mem addr 0x7fffc3313060, val 102b8777c, offset 2064
unwind: test_dwarf_unwind__krava_2:ip = 0x102b8770b (0x1e770b)
unwind: access_mem addr 0x7fffc3313088, val 7fffc3313090, offset 2104
unwind: access_mem addr 0x7fffc33130a0, val 102b87890, offset 2128
unwind: test_dwarf_unwind__krava_1:ip = 0x102b8777b (0x1e777b)
unwind: access_mem addr 0x7fffc3313108, val 10323a274, offset 2232
unwind: access_mem addr 0x7fffc3313110, val ffffffffffffffff, offset 2240
unwind: access_mem addr 0x7fffc3313118, val 102c08ed0, offset 2248
unwind: access_mem addr 0x7fffc3313120, val 1031db000, offset 2256
unwind: access_mem addr 0x7fffc3313128, val 7fffc3313130, offset 2264
unwind: access_mem addr 0x7fffc3313140, val 102b45ee8, offset 2288
unwind: '':ip = 0x102b8788f (0x1e788f)
failed: got unresolved address 0x102b8788f
unwind: failed with 'no error'
got wrong number of stack entries 0 != 8
test child finished with -1
---- end ----
Test dwarf unwind: FAILED!
We expect to resolve test__dwarf_unwind as the last symbol, but that
function can be optimized away:
$ objdump -tT /usr/bin/perf | grep dwarf_unwind
000000000083b018 g DO .data 0000000000000040 Base tests__dwarf_unwind
00000000001e7750 g DF .text 0000000000000068 Base 0x60 test_dwarf_unwind__krava_1
00000000001e76e0 g DF .text 0000000000000068 Base 0x60 test_dwarf_unwind__krava_2
00000000001e7620 g DF .text 00000000000000b4 Base 0x60 test_dwarf_unwind__krava_3
00000000001e74f0 g DF .text 0000000000000128 Base 0x60 test_dwarf_unwind__compare
00000000001e7350 g DF .text 000000000000019c Base 0x60 test_dwarf_unwind__thread
000000000083b000 g DO .data 0000000000000018 Base suite__dwarf_unwind
Fix this similar to commit fdf7c49c200d1b99 ("perf tests: Fix dwarf
unwind for stripped binaries") by marking the function as a global and
adding the 'noinline' attribute to it.
With this patch:
$ objdump -tT perf | grep dwarf_unwind
000000000083b018 g DO .data 0000000000000040 Base tests__dwarf_unwind
00000000001e80f0 g DF .text 0000000000000068 Base 0x60 test_dwarf_unwind__krava_1
00000000001e8080 g DF .text 0000000000000068 Base 0x60 test_dwarf_unwind__krava_2
00000000001e7fc0 g DF .text 00000000000000b4 Base 0x60 test_dwarf_unwind__krava_3
00000000001e7e90 g DF .text 0000000000000128 Base 0x60 test_dwarf_unwind__compare
00000000001e7cf0 g DF .text 000000000000019c Base 0x60 test_dwarf_unwind__thread
00000000001e8160 g DF .text 0000000000000248 Base 0x60 test__dwarf_unwind
000000000083b000 g DO .data 0000000000000018 Base suite__dwarf_unwind
$ ./perf test 74
74: Test dwarf unwind : Ok
Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Link: http://lore.kernel.org/lkml/20230125123442.107156-1-naveen.n.rao@linux.vnet.ibm.com
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.