| Message ID | a31f3cfd0841bea8e615ebd6f8f0ec5a0d1f1eaa.1418654436.git.naveen.n.rao@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Michael Ellerman |
| Headers | show |
Em Mon, Dec 15, 2014 at 08:20:33PM +0530, Naveen N. Rao escreveu: > If using the symbol table, symbol addresses are not being fixed up > properly, resulting in probes being placed at wrong addresses: > > # perf probe do_fork > Added new event: > probe:do_fork (on do_fork) > > You can now use it in all perf tools, such as: > > perf record -e probe:do_fork -aR sleep 1 > > # cat /sys/kernel/debug/tracing/kprobe_events > p:probe/do_fork _text+635952 > # printf "%x" 635952 > 9b430 > # grep do_fork /boot/System.map > c0000000000ab430 T .do_fork > > Fix by checking for ELF type ET_DYN used by ppc64 kernels. Sorry if this was answered already, its been a while since this was posted/discussed... Are you completely sure this is not a problem on !ppc? Woudln't it be more conservative to somehow only adjust symbols for this ET_DYN type if the arch is ppc? I.e. something like moving that adjust_symbols logic to be arch_adjust_symbols(), provide a default and then override it for ppc to include also ET_DYN? Looking at the other patches... - Arnaldo > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> > --- > tools/perf/util/symbol-elf.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c > index 06fcd1b..7ac4e4c 100644 > --- a/tools/perf/util/symbol-elf.c > +++ b/tools/perf/util/symbol-elf.c > @@ -683,7 +683,8 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, > NULL) != NULL); > } else { > ss->adjust_symbols = ehdr.e_type == ET_EXEC || > - ehdr.e_type == ET_REL; > + ehdr.e_type == ET_REL || > + ehdr.e_type == ET_DYN; > } > > ss->name = strdup(name); > -- > 2.1.3
On 2015/03/12 05:23PM, Arnaldo Carvalho de Melo wrote: > Em Mon, Dec 15, 2014 at 08:20:33PM +0530, Naveen N. Rao escreveu: > > If using the symbol table, symbol addresses are not being fixed up > > properly, resulting in probes being placed at wrong addresses: > > > > # perf probe do_fork > > Added new event: > > probe:do_fork (on do_fork) > > > > You can now use it in all perf tools, such as: > > > > perf record -e probe:do_fork -aR sleep 1 > > > > # cat /sys/kernel/debug/tracing/kprobe_events > > p:probe/do_fork _text+635952 > > # printf "%x" 635952 > > 9b430 > > # grep do_fork /boot/System.map > > c0000000000ab430 T .do_fork > > > > Fix by checking for ELF type ET_DYN used by ppc64 kernels. > > Sorry if this was answered already, its been a while since this was > posted/discussed... Are you completely sure this is not a problem on > !ppc? > > Woudln't it be more conservative to somehow only adjust symbols for this > ET_DYN type if the arch is ppc? I.e. something like moving that > adjust_symbols logic to be arch_adjust_symbols(), provide a default and > then override it for ppc to include also ET_DYN? I did check and I don't think any other arch kernel uses ET_DYN, but yes, being conservative, I could just make this a arch helper. Will do. - Naveen > > Looking at the other patches... > > - Arnaldo > > > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> > > --- > > tools/perf/util/symbol-elf.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c > > index 06fcd1b..7ac4e4c 100644 > > --- a/tools/perf/util/symbol-elf.c > > +++ b/tools/perf/util/symbol-elf.c > > @@ -683,7 +683,8 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, > > NULL) != NULL); > > } else { > > ss->adjust_symbols = ehdr.e_type == ET_EXEC || > > - ehdr.e_type == ET_REL; > > + ehdr.e_type == ET_REL || > > + ehdr.e_type == ET_DYN; > > } > > > > ss->name = strdup(name); > > -- > > 2.1.3 >
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 06fcd1b..7ac4e4c 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -683,7 +683,8 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, NULL) != NULL); } else { ss->adjust_symbols = ehdr.e_type == ET_EXEC || - ehdr.e_type == ET_REL; + ehdr.e_type == ET_REL || + ehdr.e_type == ET_DYN; } ss->name = strdup(name);
If using the symbol table, symbol addresses are not being fixed up properly, resulting in probes being placed at wrong addresses: # perf probe do_fork Added new event: probe:do_fork (on do_fork) You can now use it in all perf tools, such as: perf record -e probe:do_fork -aR sleep 1 # cat /sys/kernel/debug/tracing/kprobe_events p:probe/do_fork _text+635952 # printf "%x" 635952 9b430 # grep do_fork /boot/System.map c0000000000ab430 T .do_fork Fix by checking for ELF type ET_DYN used by ppc64 kernels. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> --- tools/perf/util/symbol-elf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)