Commit 4d3b1626 authored Nov 25, 2015 by Masami Hiramatsu Committed by Arnaldo Carvalho de Melo Nov 25, 2015

perf probe: Fix to free temporal Dwarf_Frame correctly



The commit 05c8d802 ("perf probe: Fix to free temporal Dwarf_Frame")
tried to fix the memory leak of Dwarf_Frame, but it released the frame
at wrong point. Since the dwarf_frame_cfa(frame, &pf->fb_ops, &nops) can
return an address inside the frame data structure to pf->fb_ops, we can
not release the frame before using pf->fb_ops.

This reverts the commit and releases the frame afterwards (right before
returning from call_probe_finder) correctly.

Reported-and-Tested-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Reported-by: Michael Petlan <mpetlan@redhat.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 05c8d802 ("perf probe: Fix to free temporal Dwarf_Frame")
LPU-Reference: 20151125103432.1473.31009.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 32abc2ed

tools/perf/util/probe-finder.c

+6 −7

Original line number	Diff line number	Diff line
		@@ -654,6 +654,7 @@ static int convert_to_trace_point(Dwarf_Die sp_die, Dwfl_Module mod,
		static int call_probe_finder(Dwarf_Die sc_die, struct probe_finder pf)
		{
		Dwarf_Attribute fb_attr;
		Dwarf_Frame *frame = NULL;
		size_t nops;
		int ret;

		@@ -683,26 +684,24 @@ static int call_probe_finder(Dwarf_Die sc_die, struct probe_finder pf)
		ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
		if (ret <= 0 \|\| nops == 0) {
		pf->fb_ops = NULL;
		ret = 0;
		#if _ELFUTILS_PREREQ(0, 142)
		} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
		pf->cfi != NULL) {
		Dwarf_Frame *frame = NULL;
		if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 \|\|
		dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
		pr_warning("Failed to get call frame on 0x%jx\n",
		(uintmax_t)pf->addr);
		ret = -ENOENT;
		}
		free(frame);
		return -ENOENT;
		}
		#endif
		}

		/* Call finder's callback handler */
		if (ret >= 0)
		ret = pf->callback(sc_die, pf);

		/* pf->fb_ops will be cached in libdw. Don't free it. /
		/* Since pf->fb_ops can be a part of frame. we should free it here. /
		free(frame);
		pf->fb_ops = NULL;

		return ret;