Hi Érico, On Mon, 2021-02-08 at 20:37 -0300, Érico Nogueira via Elfutils-devel wrote: > Currently, the run-backtrace-native.sh test fails on musl systems. As > seen here in the test suite log, this appears to happen because > elfutils > expects raise() to be the last function in the stack trace, which it > isn't, because unlike glibc, which uses inline functions for setting > and > resetting the signal mask, musl chose to use a normal function.
I think the testcase is way to specific indeed. It would good if it only checked some main symbol/frame names were in the backtrace. Maybe it should just check if the "raise", "main" and "_start" symbols appear in the backtrace in that order for the main thread, and "raise", "sigusr2", "stdarg", "bakctracegen" and "start"? I haven't really looked at the testcase too closely to know whether that is too simplistic. > 0x5572f0661000 0x5572f0666000 /builddir/elfutils- > 0.183/tests/backtrace-child > 0x7ff1dac68000 0x7ff1dad15000 /usr/lib/libc.so > 0x7fff70fc1000 0x7fff70fc2000 [vdso: 10694] > TID 10694: > # 0 0x7ff1dacbe3e7 __restore_sigs > # 1 0x7ff1dacbe590 - 1 raise > # 2 0x5572f0662240 - 1 main > # 3 0x7ff1dac866fa - 1 libc_start_main_stage2 > # 4 0x5572f0662329 - 1 _start > TID 10697: > # 0 0x7ff1dacbe3e7 __restore_sigs > frameno: 0 symname: __restore_sigs > # 1 0x7ff1dacbe590 - 1 raise > frameno: 0 symname: raise > # 2 0x5572f066251b - 1 sigusr2 > frameno: 1 symname: sigusr2 > # 3 0x5572f06625bc - 1 stdarg > frameno: 4 symname: stdarg > # 4 0x5572f06625e2 - 1 backtracegen > frameno: 5 symname: backtracegen > # 5 0x5572f06625fb - 1 start > frameno: 6 symname: start > # 6 0x7ff1daccf7ee - 1 start > frameno: 7 symname: start > # 7 0x7ff1dacdc91b - 1 __clone > frameno: 8 symname: __clone > # 8 0x7ff1dacdc91b - 1 __clone > frameno: 9 symname: __clone > # 9 0x7ff1dacdc91b - 1 __clone > frameno: 10 symname: __clone > #10 0x7ff1dacdc91b - 1 __clone > frameno: 11 symname: __clone > #11 0x7ff1dacdc91b - 1 __clone > frameno: 12 symname: __clone > #12 0x7ff1dacdc91b - 1 __clone > frameno: 13 symname: __clone > #13 0x7ff1dacdc91b - 1 __clone > frameno: 14 symname: __clone > #14 0x7ff1dacdc91b - 1 __clone > frameno: 15 symname: __clone > #15 0x7ff1dacdc91b - 1 __clone > frameno: 16 symname: __clone > #16 0x7ff1dacdc91b - 1 __clone > frameno: 17 symname: __clone > /builddir/elfutils-0.183/tests/backtrace: dwfl_thread_getframes: no > matching address range > /builddir/elfutils-0.183/tests/backtrace: Too many frames: 17 BTW. Here I think another issue is the __clone isn't recognized as terminating (starting?) frame. That might be a bug in musl CFI decorating of the __clone function. It should explicitly mark that function as terminating the call stack. > I have also thought about looping through stack frames until symname is > "raise", since other libcs (and possibly even glibc?) could one day add > a function call inside raise(), which would break this test. What do you > think of that solution? I think that is a better approach. Cheers, Mark
