Messages in this thread Patch in this message | | | From | Jiri Olsa <> | Subject | [PATCH] perf test: Fix signal test inline assembly | Date | Fri, 11 Sep 2020 15:00:05 +0200 |
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When compiling with DEBUG=1 on Fedora 32 I'm getting crash for 'perf test signal':
Program received signal SIGSEGV, Segmentation fault. 0x0000000000c68548 in __test_function () (gdb) bt #0 0x0000000000c68548 in __test_function () #1 0x00000000004d62e9 in test_function () at tests/bp_signal.c:61 #2 0x00000000004d689a in test__bp_signal (test=0xa8e280 <generic_ ... #3 0x00000000004b7d49 in run_test (test=0xa8e280 <generic_tests+1 ... #4 0x00000000004b7e7f in test_and_print (t=0xa8e280 <generic_test ... #5 0x00000000004b8927 in __cmd_test (argc=1, argv=0x7fffffffdce0, ... ...
It's caused by __test_function being in .bss section:
$ readelf -a ./perf | less [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [28] .bss NOBITS 0000000000c356a0 008346a0 00000000000511f8 0000000000000000 WA 0 0 32
$ nm perf | grep __test_function 0000000000c68548 B __test_function
I guess most of the time we're just lucky the inline asm ended up in .text section, so making it specific explicit with push and pop section cluases.
$ readelf -a ./perf | less [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [13] .text PROGBITS 0000000000431240 00031240 0000000000306faa 0000000000000000 AX 0 0 16
$ nm perf | grep __test_function 00000000004d62c8 T __test_function
Cc: Wang Nan <wangnan0@huawei.com> Fixes: 8fd34e1cce18 ("perf test: Improve bp_signal") Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- tools/perf/tests/bp_signal.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/tools/perf/tests/bp_signal.c b/tools/perf/tests/bp_signal.c index da8ec1e8e064..cc9fbcedb364 100644 --- a/tools/perf/tests/bp_signal.c +++ b/tools/perf/tests/bp_signal.c @@ -45,10 +45,13 @@ volatile long the_var; #if defined (__x86_64__) extern void __test_function(volatile long *ptr); asm ( + ".pushsection .text;" ".globl __test_function\n" + ".type __test_function, @function;" "__test_function:\n" "incq (%rdi)\n" - "ret\n"); + "ret\n" + ".popsection\n"); #else static void __test_function(volatile long *ptr) { -- 2.26.2
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