Messages in this thread | | | Date | Fri, 26 Jun 2015 16:55:29 +0300 | From | Adrian Hunter <> | Subject | Re: [PATCH] perf tools: don't adjust symbols in vDSO |
| |
On 26/06/15 15:23, Will Deacon wrote: > On Thu, Jun 25, 2015 at 02:32:13PM +0100, Adrian Hunter wrote: >> On 24/06/15 19:17, Will Deacon wrote: >>> Commit 922d0e4d9f04 ("perf tools: Adjust symbols in VDSO") changed the >>> ELF symbol parsing so that the vDSO is treated the same as ET_EXEC and >>> ET_REL binaries despite being an ET_DYN. >>> >>> This causes objdump, which expects relative addresses, not to produce >>> any output in conjunction with perf annotate, which cheerfully passes >>> absolute addresses when trying to disassemble vDSO functions. >>> >>> This patch avoids marking the vDSO as requiring adjustment of symbol >>> addresses, allowing the relative program counter to be used instead. >>> >>> Cc: Vladimir Nikulichev <nvs@tbricks.com> >>> Cc: Adrian Hunter <adrian.hunter@intel.com> >>> Cc: Namhyung Kim <namhyung@kernel.org> >>> Reported-by: Kristina Martsenko <kristina.martsenko@arm.com> >>> Signed-off-by: Will Deacon <will.deacon@arm.com> >>> --- >>> >>> Not sure why I've just started seeing this, but it appears to affect >>> both x86 and arm64. Also, if I revert the patch above then the issue >>> it supposedly fixed doesn't resurface. Maybe it was just masking another >>> bug that has since been addressed? >> >> No the problem still appears on older kernels. > > Can you be more specific, please? I tried with a 3.16 kernel (that I happen
3.13 Ubuntu kernel
> to be running on my box) but perf doesn't even detect the vdso there, > regardless of this patch.
Don't know what you mean about not detecting vdso
> >> Probably could look at the vdso section/program headers to decide if it >> needs adjustment or not. > > Did the x86 kernel change in this regard? Why isn't the vDSO always ET_DYN?
I guess, but it is ET_DYN
| |