Messages in this thread Patch in this message | | | Date | Mon, 5 Nov 2012 23:49:16 +0100 | From | Hannes Frederic Sowa <> | Subject | [PATCH] [perf] convert_variable_type does not correctly check type of arrays |
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While casting an array of (unsigned) chars to a string, perf does not check the containing type but only the opaque type and is bailing out:
$ perf probe -v -a 'neigh_destroy:22 dev->name:string' probe-definition(0): neigh_destroy:22 dev->name:string symbol:neigh_destroy file:(null) line:22 offset:0 return:0 lazy:(null) parsing arg: dev->name:string into type:string dev, name(1) 1 arguments Use vmlinux: /home/hannes/linux/vmlinux Using /home/hannes/linux/vmlinux for symbols Probe point found: neigh_destroy+115 Searching 'dev' variable in context. Converting variable dev into trace event. converting name in dev name type is (null). Failed to cast into string: name is not (unsigned) char *. Failed to find 'dev' in this function. An error occurred in debuginfo analysis (-22). Error: Failed to add events. (-22)
After the code flow ensures that type could only be a pointer or array type, call die_get_real_type unconditionally again to fetch the containing type and have further validation been done on that Die.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> --- tools/perf/util/probe-finder.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index 1daf5c1..2a61ea5 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -413,12 +413,13 @@ static int convert_variable_type(Dwarf_Die *vr_die, dwarf_diename(vr_die), dwarf_diename(&type)); return -EINVAL; } + if (die_get_real_type(&type, &type) == NULL) { + pr_warning("Failed to get a type information.\n"); + return -ENOENT; + } + pr_debug("containing type of %s is %s.\n", + dwarf_diename(vr_die), dwarf_diename(&type)); if (ret == DW_TAG_pointer_type) { - if (die_get_real_type(&type, &type) == NULL) { - pr_warning("Failed to get a type" - " information.\n"); - return -ENOENT; - } while (*ref_ptr) ref_ptr = &(*ref_ptr)->next; /* Add new reference with offset +0 */
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