This is why symsmap_addr_dso simply returns NULL when symsfind_dso also returns NULL. In that case, the values of dso_name and dso_offset are not changed. If the dso_name and dso_offset variables have a garbage value before calling symsmap_addr_dso, those garbage values are maintained after calling symsmap_addr_dso.
This patch fixes the issue by reinitializing dso_name and dso_offset variables before calling syms__map_addr_dso.
FYI, there is another PR(https://github.com/iovisor/bcc/pull/4862) to fix the issue by changing syms__map_addr_dso API.
This PR is to fix the issue in a simple way as the above PR is pending now.
…tacktrace
offcputime may display inaccurate DSO information in the stacktrace. Here's an example of the issue:
It shows the same DSO offset for different addresses, which is incorrect.
This is why symsmap_addr_dso simply returns NULL when symsfind_dso also returns NULL. In that case, the values of dso_name and dso_offset are not changed. If the dso_name and dso_offset variables have a garbage value before calling symsmap_addr_dso, those garbage values are maintained after calling symsmap_addr_dso.
This patch fixes the issue by reinitializing dso_name and dso_offset variables before calling syms__map_addr_dso.
FYI, there is another PR(https://github.com/iovisor/bcc/pull/4862) to fix the issue by changing syms__map_addr_dso API. This PR is to fix the issue in a simple way as the above PR is pending now.